Document d1EKVBaKdQ41jpggVdMXZLXQ

Go to Table of Contents Guidelines for Cooperation with the t, >' Alaska Dam Safety Program #f e ,ll k . V m l A \3 s f %' - Prepared by Dam Safety and Coastructiori Unit Water Resources Section Division of Mining^ Land and Water Alaska Department of Natural Resources Sierra Club v. EPA 18cv3472 NDCA Tier 10 June 2005 Attachment F Page 1 of 230 ED 002061 00172725-00001 Go to "['able of Contents Guidelines for Cooperation with the Alaska Dam Safety Program Prepared by Dam Safety and Construction Unit Water Resources Section Division of Mining, Land and Water Alaska Department of Natural Resources June 30, 2005 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 2 of 230 ED 002061 00172725-00002 Go to Table of Contents About the Cover The cover photographs depict the five stages in the regulatory life of a dam, which are explained in Chapter 4, Top left: Application for New Construction A design cross section from the Fort Knox Tailings Dam located near Fairbanks. Compliments of Clyde Gillespie and Fairbanks Gold Mining, Inc. Top right: Construction An interim raise under construction at the Fort Knox Tailings Dam. Photograph by Charles Cobb. Center: Operation Steve Anderson conducting the visual inspection for a periodic safety inspection at the Cannery Creek Dam owned by the Alaska Department of Fish and Game and operated by the Prince William Sound Aquaculture Association. Photograph by Charles Cobb. Bottom Left: Remediation A "five-year" flood overtopping the Kake Dam in Southeast Alaska indicates that remediation is needed to address an inadequate spillway capacity. Photograph by Thomas Hanna. Bottom right: Closure The remains of the Kake Dam after the majority of the dam structure was removed following a breach in the darn that occurred during a high-water event. Photograph by Charles Cobb. Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 3 of 230 ED 002061 00172725-00003 Go to Table of Contents This project was developed through financial assistance from the National Dam Safety Program. Thanks to the Federal Emergency Management Agency and the Association of State Dam Safety Officials for their support of the Alaska Dam Safety Program. Special thanks are directed to Judy Griffin of Word Wrangling for her expert help in designing, formatting, editing, and revising these guidelines. Thanks to Brett Flint, Dan Johnson, Cecil Urlich, and others at URS Corporation for their efforts in developing the initial draft of this document. Thanks to John Magee and Bob Scher at R&M Consultants Inc. for their contributions to the final version. Thanks to Clyde Gillespie of Fairbanks Gold Mining Inc., Howard Weston of the City of Kodiak, and Stan Foo of the Alaska Department of Natural Resources for their time and comments on the final draft. Thanks to Gary Prokosch, Bob Loeffler, and all of my colleagues at the Division of Mining, Land and Water for their support of the Dam Safety and Construction Unit. Finally, thanks to all of the dam owners and operators for their cooperation with the Alaska Dam Safety Program. Charles F. Cobb, P. E. State Dam Safety Engineer Alaska Department of Natural Resources G uidelines for C ooperation with the A laska D am Safety Program Sierra Club v. EPA 18cv3472 NDCA m Tier 10 Revision 1 June 30, 2005 Attachment F Page 4 of 230 ED 002061 00172725-00004 Contente Chapter Page ACKNOWLEDGEMENTS............................................................................................................. iii ABBREVIATIONS...........................................................................................................................v ii 1 WELCOME TO THE ALASKA DAM SAFETY PROGRAM.................................................1-1 1.1 Introduction......... ............ 1-1 1.2 Objectives of Guidelines........................................................................................................... 1-2 1.3 Project Responsibilities............................................................................................................. 1-3 1.4 Disclaimer.................................................................................................................................. 1-7 2 BASIS FOR REGULATION OF ALASKA 2.1 History of Dam Safety in Alaska.............................................................................................2-1 2.2 Dam Safety Statutes and Regulations....... ............ 2-2 2.3 Definition of a State Jurisdictional Dam................................................................................. 2-5 2.4 Hazard Potential Classification............................................................................................... 2-9 2.5 Associated Permits and RegulatoryAgencies...................................................................... 2-11 3 CERTIFIC ATES OF APPROVAL................................................................................................ 3-1 3.1 Operation.................................................................................................................................... 3-1 3.2 Construction............................................................................................................................... 3-2 3.3 Applications for Certificates of Approval........ ........... 3-3 3.4 Application Fee.......................................................................................................................... 3-4 4 FIVE STAGES IN THE REGULATORY LIFE OF A DAM.....................................................4-1 4.1 Application for New Dam Construction................................................................................4-1 4.2 Construction............................................................................................................................... 4-4 4.3 Operation.................................................................................................................................... 4-6 4.4 Remediation ............. ......4-6 4.5 Closure........................................................................................................................................ 4-6 5 CONSTRUCTION APPLICATION DETAILS..........................................................................5-1 5.1 Initial Application Package,,........... ........ 5-1 5.2 Preliminary Design Package.................................................................................................... 5-6 5.3 Detailed Design Package........................................................................................................ 5-10 5.4 Final Construction Package.................................................................................................... 5-13 6 DESIGNING A DAM IN 6,1 Hydrology and Hydraulics.....................................................................................................6-2 G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A IV Tier 10 Revision 1 June 30, 2005 Attachment F Page 5 of 230 ED 002061 00172725-00005 Go to Table of Contents Table of Contents 6.2 Stabilitjv.......................................................................................................................................6-5 6.3 Seismicity....................................................................................................................................6-5 6.4 Seepage........................................................................................................................................6-8 6.5 Cold Regions....... ....................................................................................................................6-10 7 CONSTRUCTING THE DAM......................................................................................................7-1 7.1 Preconstruction Plans...............................................................................................................7-1 7.2 Construction Quality Assurance/Quality Control...............................................................7-2 7.3 Post-Construction Submittals..................................................................................................7-4 8 OPERATIONS AND MAINTENANCE PROGRAM...............................................................8-1 8.1 Operations and Maintenance Manual....................................................................................8-1 8.2 Monitoring..................................................................................................................................8-2 8.3 Operator Training Program.....................................................................................................8-3 9 EMERGENCY ACTION PLANNING.........................................................................................9-1 9.1 Emergency Action Plans...........................................................................................................9-2 9.2 Emergency Ac bon PIan Exerd ses.................................................................................... 9-4 9.3 Dam Failure Analysis................................................................................................................9-5 .j 9.4 Inundation Maps.....................................................................................................................9-10 10 INSPECTIONS............................................................................................................................... 10-1 10.1 Construction Inspections......................................................................................................10-1 10.2 Routine inspections..............................................................................................................10-1 10.3 Extraordinary Inspections....................................................................................................10-2 10.4 Periodic Safety Inspections..................................................................................................10-3 10.5 ADNR Field inspections................... ......10-8 11 PERFORMANCE AND INCIDENT REPORTING ................................................................11-1 11.1 Reporting Guidelines............................................................................................................11-2 11.2 Reporting Requirements.......................................................................................................11-2 12 REMEDIAL INVESTIGATIONS AND DECISION MAKING..........................................12-1 12.1 Remedial investigations and Repairs.................................................................................12-1 12.2 Emergency Actions...................... .12-2 12.3 Techniques for Making- Decisions....................................................................................... 12-3 13 CLOSURE .......................................................................................................................................13-1 13.1 Removal..................................................................................................................................13-1 13.2 Abandonment........................................................................................................................13-2 13.3 Other Issues.................. 13-5 14 REFERENCES.................................................................................................................................14-1 G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A V Tier 10 Revision 1 June 30, 2005 Attachment F Page 6 of 230 ED 002061 00172725-00006 Go to Table of Contents T able of C ontents Appendix A Hazard Potential Classification and Jurisdictional Review Form B Example of Certificate of Approval to Operate a Darn C Example of Certificate of Approval to Construct a Darn D Project Data Sheet E Sample Ou tline for a Simple Operations and Maintenance Manual for a Small Dam F Performance Parameters for Darn Safety Monitoring G Alaska Darn Safety Program Visual Inspection Checklist H Reporting the Performance of Dams I A Role for Risk Assessmen t in Dam Sa fety Management J Example of a Simple Decision Matrix Figure 2-1 jurisdictional Dam Based on Storage Capacity and Height.................................................... 2-6 2-2 Jurisdictionai Dam Based on Height Only................................................................................. 2-6 2-3 Summary of Conditions for State jurisdiction of a Dam...........................................................2-7 2-4 Typical Dam Section...................................................................................................................... 2-8 2-5 Typical Dam Profile....................................................................................................................... 2-8 2-6 Ring Dike .........................................................................................................................................2-8 2-7 Saddle Dam or Off-Stream Dam................................................................................................. 2-8 4-1 Darn Safety Application Review Process................ .......... .......... .......... .......... .......... .......... 4-2 4-2 Dam Safety Construction Review Process.......... .......... .......... .......... ......... .......... .......... .4-5 4- 3 Darn Safety Operations Review' Process.................. .4-7 5- 1 Relative Cost-to-Change Curve............... 5-2 6- 1 Comparison of Dam Failures in the United States andAlaska................................................ 6-2 9-1 Attenuation of Flood Peak Following a Dam Break.................................................................9-9 Table 2- 1 Hazard Potential Classification Summary..............................................................................2-10 3- 1 Application Fee Ca Iculation........................................................................................................ 3-5 5- 1 Acceptable Levels of Evaluation for Proposed HazardPotential Classifications................. 5-4 6- 1 General Guidance for a Stability Analysis................................................................................ 6-5 6- 2 Operating- and Safety-Level Seismic Hazard Risk.................................................................. 6-7 7- 1 CQA/QC Levels Based on Hazard Potential Classifications................ 7-3 8- 1 Suggested Monitoring and Instrumentation Levels....... .... 8-3 9- 1 Acceptable Dam Breach Parameters.... ........ 9-8 11-1 Reporting of Dam Incidents Based on Hazard Potential Classification ..............................11-2 Guideunes for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A VI Tier 10 Revision 1 June 30, 2005 Attachment F Page 7 of 230 ED 002061 00172725-00007 Ci to Table of Contents ABBREVIATIONS AAC ADEC ADF&G ADNR ASDSO ADSP AS CQA CQA/QC CQC CSI Dam Safety DQA DQC EAP FEMA FERC H MR-54 IDF MCE MDE NDSP NPDP QBE O&M PGA PMF Alaska Administrative Code Alaska Department of Environmental Conservation Alaska Department of Fish and Game Alaska Department of Natural Resources Association of State Dam Safety Officials Alaska Dam Safety Program Alaska Statute construction quality assurance construction quality assurance/quality control construction quality control Construction Specifications Institute Dam Safety and Construction Unit design quality assurance design quality control emergency action plan Federal Emergency Management Agency Federal Energy Regulatory Commission Hydrometeorological Report 54 inflow design flood maximum credible earthquake maximum design earthquake National Dam Safety Program National Performance of Dams Program operating basis earthquake operations and maintenance peak ground acceleration probable maximum flood G uidelines for C ooperation with vn the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 8 of 230 ED 002061 00172725-00008 Go to Table of Contents PMP PSI TADS USAGE USBR USCOLD USDA uses USSD WSDOE probable maximum precipitation periodic safety inspection Training Aids for Dam Safety U,S. Army Corps of Engineers U.S. Bureau of Reclamation U.S. Committee on Large Dams U.S. Department of Agriculture U.S. Geological Survey U.S. Society on Dams Washington State Department of Ecology A bbreviations G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A vm Tier 10 Revision 1 June 3 0,2005 Attachment F Page 9 of 230 ED 002061 00172725-00009 Go to Table of Contents Guidelines for Cooperation with the Alaska Dam Safety Program Chapter 1 WELCOME TO THE ALASKA DAM SAFETY PROGRAM 'Ll Introduction .......................................................................................................................... 1-1 1.2 Objectives of Guidelines...................................................................................................... 1-2 1.3 Project Responsibilities........... .............................................................................................1-3 1.3.1 Alaska Department of Natural Resources................................................................ 1-3 1.3.2 Owner of Dam ........... 1-3 1.3.3 Operator of Dam........................................................................................................... 1-4 1.3.4 Qualified Engineer....................................................................................................... 1-4 1.3.5 Construction Contractors............................................................................................ 1-6 1.3.6 Emergency Responders............................................................................................... 1-7 1.4 Disclaimer ..............................................................................................................................1-7 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 10 of 230 ED 002061 00172725-00010 Go to Table of Contents Chapter 1 WELCOME TO THE ALASKA DAM SAFETY PROGRAM In this chapter: > Purpose o f the Alaska Dam Safety Program > Description o f responsibilities assigned to various entities > A disclaimer and discussion of liability 1.1 Introduction Communication is the key to the safety of dams. Design drawings, operation and maintenance manuals, inspection reports, emergency action plans, and other documents are simply methods of communicating important information directly related to the safe design, construction, and operation of dams. Because dams are typically complex, unique, engineered structures with a long service life, the specific nature of this communication will be similarly complex and unique, and will occur during a long period of time. The Alaska Dam Safety Program (ADSP) is administered as a cooperative effort between the Alaska Department of Natural Resources (ADNR) and the various persons, businesses, agencies, and other interests that are involved in the design, construction, and operation of dams. To foster cooperation, communication between these parties must be effective and efficient. These guidelines are intended to promote communication, understanding, and agreement by presenting an overview of the various aspects of the ADSP. If cooperative relationships can be established, the entire community will benefit. By anticipating the scope of the communication, all of the entities involved will better understand the level of commitment necessary to accomplish the objectives of a particular project. The Mission The m ission of the A laska Dam Safety Program is to protect life and property in Alaska through the effective collection, evaluation, understanding and sharing of the information necessary to identify, estimate and mitigate the risks created by dams. Safe dams are the ultimate objectives of the ADSP. To achieve these goals, the program must be rational, technically sound, balanced and equitable. The ADNR seeks to establish these attributes through the publication, review, and refinement of this document. G uidelines for C ooperation with the A laska Dam Safety Program Sierra Club v. E P A 18cv3472 N D C A 1-1 Tier 10 Revision 1 June B O ,2005 Attachment F Page 11 of 230 ED 002061 00172725-00011 Go to Table of Contents C hapter 1, W elcome to the A laska D am Safety Program 1.2 Objectives of Guidelines The Guidelines for Cooperation with the Alaska Darn Safety Program is intended to establish a consistent basis for communication between the ADNR, dam owners and operators, and various other entities involved in the planning, design, construction, operation, and regulation of dams in Alaska. This document is intended as a compendium for guidance purposes only --it is not a restatement of statutes and regulations, nor is it a detailed design guide. The objectives of these guidelines are described below: To define the administrative basis of the ADSP To outline the minimum information required to obtain the various certificates of approval necessary to construct and opera te dams under program jurisdiction To outline an application and review process to obtain the various certificates of approval issued under the ADSP To provide a consistent template for the design, construction, and operation of dams in Alaska while still recognizing that every dam is unique To highlight importan t design aspects of dams that are unique to Alaska or otherwise merit specific attention To recommend acceptable design approaches, references, and performance levels based on the hazard potential classification of the dam To provide guidance on the preparation and implementation of an operations and maintenance (O&M) program and a periodic safety inspection (PSI) program To provide guidance on the preparation, implementation, training, and exercise of emergency action plans (EAPs) To outline other aspects of the ADSP To provide a forum for, and encourage communication and cooperation between, dam owners and ADNR to work together in siting, designing, constructing, repairing, modifying, operating, and closing dams in Alaska About the Guidelines These guidelines consist of text, lists, tables, figures, and sidebars. The form at is intended to minimize boredom and m axim ize content, at the expense of nebulous or superfluous detail. Tables and figures contain important information that may require som e study to understand. Sidebars are intended to present related noteworthy information that does not necessarily fit the flow of the section. References contain additional detailed information and guidance that m ay be used to accomplish the mission. Comments on these guidelines are welcome. GUIDELINES FOR COOPERATION WITH the A laska Dam Safety Program Sierra Club v. EPA 18cv3472 NDCA l -2 Tier 10 REVISION l June 30, 2005 Attachment F Page 12 of 230 ED 002061 00172725-00012 Go to Table of Contents C hapter . W elcome to the A laska Da m Safety Program 1.3 Project Responsibilities 1.3.1 Alaska Department of Natural Resources Alaska Statute (AS) 46.17.020 requires the ADNR to employ a professional engineer to "supervise the safety of dams and reservoirs" in Alaska. The State Dam Safety Engineer is the authorized representative of the commissioner of ADNR responsible for the following: Adopting regula tions and issuing orders necessary for ensuring dam safety Providing routine administration of the ADSP and the Dam Safety and Construction Unit (Dam Safety) of the ADNR Classifying dams based on the potential hazard to lives and property created by the darn Approving the design, construction, operation, and inspection of dams through "certificates of approval," which are issued based on specific information submitted to Dam Safety for review Identifying unsafe dams that compromise the mission of the ADSP, and taking the necessary steps to mitigate those risks Raising the level of compliance for jurisdictional dams that are out of compliance with state dam safety regulations Enforcing the dam safety statu tes and regulations through appropriate legal actions, if necessary, including issuing injunctions, assuming operational control of the dam, breaching the dam, or other activities necessary to mitiga te the risk Providing information and educational material about dams in Alaska and dams in general, including the Alaska Dam Inventory, Training Aids for Dam Safety, conference proceedings, and other resources. Levels of Authority at ADNR |I Commissioner, ADNR | Director, Division o f Mining, Land |! and Water | Chief, Water Resources Section | State Dam Safety Engineer, Dam |! Safety and Construction Unit 1 1.3.2 Owner of Dam According to AS 46.17.900(6), the "owner" of a dam means a person who owns, controls, operates, maintains, manages, or proposes to construct a dam or reservoir, and includes a public utility and the appointed or authorized agents, employees, lessees, receivers, or trustees of an owner. The owner is ultimately responsible for the safety of the dam. As such, the owner bears all liabilities associated with the dam. Therefore, the owner is directly responsible for mitigating the risks created by the dam. The dam owner's responsibilities include the following: Understanding the risks created by the dam G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 1-3 Tier 10 Revisio n ! June 30, 2005 Attachment F Page 13 of 230 ED 002061 00172725-00013 Go to Table of Contents C hapter 1. W elcome to the A laska Da m Safety Program Developing policies, plans, and procedures necessary for complying with the requirements of the applicable dam safety statutes and regulations Sustaining the project by providing all funding necessary to design, construct, operate, maintain, repair, and, if necessary, remove the dam at the end of the life of the project Hiring personnel qualified to manage and operate a dam in a safe manner Typical Dam Owners in Alaska Municipalities State and federal agencies Native corporations Private and public owned businesses and corporations Retaining qualified engineering consultants and contractors to complete any work beyond the expertise of the owner or the owner's employees Ensuring the quality and success of the overall project 1.3.3 Operator of Dam For purposes of these guidelines, the "operator" of a dam is considered to be that legal extension of the owner of the dam who is actually involved in the daily operation of the dam. As such, the operator of the dam is responsible for the following: Executing those policies, plans, and procedures, developed by the owner, necessary for complying with the requirements of the applicable dam safety statutes and regulations Developing and performing the requirements of the O&M program Monitoring the performance of the dam under all conditions (including routine and extraordinary inspections), reading instrumentation, and analyzing and reporting of data Developing and maintaining the EAP, activating the plan when necessary, executing the responsibilities of the operator outlined in the plan, and exercising and revising the plan on a regular basis to ensure that the plan is current Maintaining all records associated with the dam, including design and construction records, routine inspection records, PSI reports, incident reports, and certificates of approval Developing and implementing recurrent training programs to educate employees on their specific duties related to the darn Typical Dam Operators in Alaska Public works departments Utilities Mines Fish hatcheries and processors 1.3.4 Qualified Engineer Because a dam is a unique and complex engineered structure that has certain associated risks, an experienced engineer is required to assure that a dam is designed, built, and operated with appropriate concerns for safety. A "qualified engineer" is defined in the Alaska dam safety regulations under Title 11, Chapter 93, Section 193, of the Alaska Administrative Code (11 AAC G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 1-4 Tier 10 Revisio n ! June 30, 2005 Attachment F Page 14 of 230 ED 002061 00172725-00014 Go to Table of Contents C hapter 1, W elcome to the A laska D am Safety Program 93.193). To meet the criteria for a qualified engineer, an individual must be a civil engineer currently licensed to practice in Alaska under the State Board of Registration for Architects, Engineers, and Land Surveyors. The regulations also state that the qualified engineer must have at least five years of experience as a licensed or registered professional civil engineer. In addition, an engineer who may certify hazard potential classifications, design engineering reports, design and construction drawings, construction completion reports, and construction record drawings must have "significant work experience in the design, construction, inspection and safety of dams" [11 AAC 93.193(a)(3)]. The regulations allow a slightly lower qualification for engineers who may conduct and certify PSIs of dams under 11 AAC 93.159. Those engineers must have "sufficient work experience to determine the safety of the particular dam being inspected and to make reliable recommendations regarding the operations and maintenance of that dam, inspections of that dam, and other matters related to the safety of that dam." AS 46.17.050 indicates that qualified engineers who conduct PSIs must be approved by Dam Safety. Within these guidelines, references to the "engineer" are widespread and context dependent. A variety of engineers are referred to and described; examples are "engineer of record" and "construction inspection engineer." For purposes of these guidelines, references to the engineer assume a qualified engineer as defined by the regulations, within the context of the discussion. Generally speaking, the engineer is responsible for the follow'ing: Maintaining a curriculum vitae that demonstrates relevant experience to meet the qualifications described in 11 AAC 93.193 Understanding the regulatory setting of a project, the intent of the regulations, and the work necessary to accomplish the desired outcome, without taking shortcuts that circumven t the regulations and compound the risks Typical Qualified Engineers in Alaska Employees of engineering companies independent consultants Employees of dam owners or operators Becoming an "engineer of record" by placing a signature and seal on reports, drawings, specifications, and other engineering work products. ["Sealed" is defined in 11 AAC 93.201(12) to mean "prepared by an engineer or a person under that engineer's direct supervision, and bearing the signature and seal of that engineer as required by AS 08.48.221 and 12 AAC 36.185."] Recognizing personal limitations and assembling a team of engineers as required to address all of the broad range of engineering disciplines typically associated with a dam, including additional engineers of record to certify details associated with other disciplines such as electrical or structural components Locating and designing dams with safety as the primary goal by using technically sound and complete engineering methodology that represents the level of care exercised by professional engineers across the nation Observing and documenting the construction of dams in a manner consistent with the approved construction quality assurance plan G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 1 -5 Tier 10 Revision 1 June 30, 2005 Attachment F Page 15 of 230 ED 002061 00172725-00015 Go to Table of Contents C hapter . W elcome to the A laska Da m Safety Program Communicating effectively with the owner, Dam Safety, and other entities with complete information packages that contain well-written reports and specifications and good-quality drawings Refining and executing the scope of work necessary to complete a detailed PSI of a dam and developing a clear, quality report Processing and analyzing monitoring and inspection data in a manner that leads to technically sound, defensible conclusions Recommending reliable, cost-effective solutions to mitigate problems discovered during the life of the project 1.3.5 Construction Contractors Construction contractors must possess appropriate qualifications, licenses, permits, and authorizations specific to the project and as required for constructing dams or performing other related work such as repairs or construction of appurtenant structures. Contractors are responsible for the following: Performing the work in accordance with the approved plans and specifications without deviation, unless the engineer of record and Dam Safety have formally approved the change Identifying and reporting any aspect of the design or construction that could affect the safe performance of the finished product, or may need special attention or specialized construction techniques to accomplish design objectives Identifying and reporting any changed conditions that occur or are discovered during construction that require special attention or additional work to meet the intent of the design Developing and implementing a construction quality control plan that results in a goodquality product constructed in accordance with the plans and specifications Recording or assisting in the recording of all information necessary to develop a complete and accura te record of the construction, including record drawings, photographs, quality control test results, product brand names and specifications, and other important information Developing the additional plans necessary to complete the project in a manner that ensures the safety and protection of the site personnel and the downstream interests Cooperating with the engineers, quality assurance inspectors, and Dam Safety Other Implied Responsibilities The descriptions of responsibilities included in these sections are not comprehensive. Other responsibilities certainly exist. Each entity m ust understand its own obligations under the related statutes and regulations, business contracts, written and verbal agreements, and codes of ethics. G uidelines for.C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA -6 Tier 10 Revision June 30, 2005 Attachment F Page 16 of 230 ED 002061 00172725-00016 Go to Table of Contents C hapter 1. W elcome to the A laska Da m Safety Program 1.3.6 Emergency Responders Entities that respond to a dam-related emergency may include the dam owner and operator, local fire and police departments, local emergency response managers and healthcare providers, civilian relief organizations, Alaska State Troopers, Alaska Division of Emergency Services, the National Weather Service, the United States Coast Guard, the Alaska Department of Environmental Conservation, the ADNR, and others. All entities that agree to participate as responders and are identified in an EAP for a dam are responsible for the following: Becoming familiar with the EAP and the potential impacts that could result if the dam were to fail Understanding their respective roles in an emergency and preparing adequately in advance to respond appropriately if an emergency situation develops Participating and cooperating in exercises of EAPs that are coordinated and conducted by the operator of the dam Reviewing the contents of the plan related to their respective responsibilities and contributing constructive advice on improvements to the plan Developing the necessary policies or procedures within their respective organizations so that knowledge of the EAP and associated responsibilities is prevalent within the organization, as appropriate 1.4 Disclaimer This document is intended to provide only general guidance about the administration of the ADSP. It is not intended as a detailed design manual, specification, or regulation. The dam safety statutes and regulations (AS 46.17 and Article 3 in 11 AAC 93) are the legal governance for the ADSP. Dam Safety review's each project on an individual basis and may require information, studies, and submittals that are not discussed herein, as deemed necessary to ensure that a dam is as safe as is reasonably possible. The dam safety statutes provide indemnity to the ADNR regarding dams and reservoirs. AS 46.17.110 states: ... A person may not bring an action against the state, the department, or agents or employees of the state, for the recovery of damages caused by the partial or total failure of a dam or reservoir, or by the operation of a dam or reservoir, or by an act or omission in connection with (a) approval of the construction of a dam or reservoir, or approval of floodhandling plans during or after construction; G UIDELINES FOR CO O PERATIO N WITH the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA i -7 Tier 10 Revision I June 30, 2005 Attachment F Page 17 of 230 ED 002061 00172725-00017 Go to Table of Contents C hapter 1. W elcome to the A laska Da m Safety Program (b) issuance or enforcement of orders relating to maintenance or operation of a dam or reservoir; (c) control or regulation of the dam or reservoir; (d) measures taken to protect against failure of the dam or reservoir during an emergency; or (e) investigations or inspections authorized under this chapter. An exception is allowed for "the recovery of damages caused by an action undertaken by a dam owner that was negligently ordered by the state over the owner's objection." Nevertheless, the owner, operator, and engineer have primary responsibili ty for the safe design, construction, and operation of a darn. Historically, the standard of care that a dam owner exercises is closely examined by the courts when assessing the liability for the failure of a dam (Association of State Dam Safety Officials [ASDSO], undated). Legally Speaking Strict liability and negligence are legal concepts applied to dam owners b y courts in the United States when ruling on liabilities associated with dams. Compliance with the Alaska Dam Safety Program is intended to establish a m inimum standard of care; however, additional effort by the dam owner m ay be required to fully understand and manage the associated risks and liabilities of owning a dam. Finally, references herein to textbooks, technical papers, guidelines, Web sites, and otherresources do not imply endorsement by the ADNR or suitability for any specific purpose of the user. Each submittal to Dam Safety will be evaluated based on its individual and specific merit at the sole discretion of the commissioner of the ADNR. Funding provided by the Federal Emergency Management Agency for the development and revision of this document does not imply their endorsement of the information contained herein. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 1 -8 Tier 10 Revision 1 June 30, 2005 Attachment F Page 18 of 230 ED 002061 00172725-00018 Go to Table of Contents Guidelines for Cooperation with the Alaska Dam Safety Program Chapter 2 BASIS FOR REGULATION OF ALASKA DAMS 2.1 History of Dam Safety in Alaska ....................................................................................... 2-1 2.2 Dam Safety Statutes and Regulations................................................................................ 2-2 2.2.1 Alaska Statutes............................................................................................................ 2-2 2.2.2 Alaska Administrative Code..................................................................................... 2-3 2.3 Definition of a Sta te Jti risdic fional Dam ....... ............................................................ 2-5 2.4 Hazard Potential Classification........................................................................................... 2-9 2.5 Associated Permits and Regulatory Agencies.......... ........... .................................. . 2-11 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 19 of 230 ED 002061 00172725-00019 Go to Table of Contents Chapter 2 BASIS FOR REGULATION OF ALASKA DAMS In this chapter: > The history of the Alaska Dam Safety Program > Sum m ary of Alaska dam safety statutes and regulations and the definition of a dam > D iscussion of the hazard potential classification for dam s in Alaska 2.1 History of Dam Safety in Alaska During the 1970s, several dams failed in both Alaska and the Lower 48. These incidents resulted in numerous deaths, including one in Alaska, and millions of dollars in property damage. In 1972, Public Law 92-367 was signed. This law required the U.S. Army Corps of Engineers (USAGE) to inventory non-federal dams in America and make recommendations for a National Dam Safety Program. As early as 1973, Alaska passed laws that attempted to regulate the construction of dams in the state. In 1975, Senate Bill 362 titled "An Act Relating to Supervision of Safety of Dams and Reservoirs" attempted to delegate responsibility to the Department of Public Works, but failed to pass the Ninth Legislative Session. On May 29,1978, Governor Jay S. Hammond signed an agreement for the Alaska Department of Transportation and Public Facilities to jointly review specific dams with the USAGE. Subsequent discussions within the state led to the conclusion that the ADNR had authority related to dam safety through the Water Use Act (AS 46.15) and 11 AAC 72.060, Dam Construction (1973). However, the ADNR expressed a great deal of concern because the statutes and regulations inadequately addressed important dam safety issues such as routine safety inspections, operation and maintenance, and liability. On December 29,1979, revised dam safety regulations became effective under Article 3 of 11 AAC 93, Dam Safety and Construction. By 1982, the Water Management Section of the Division of Land and Water Management began to organize the ADSP. The efforts of the entire staff of the central region Water Management Section were directed toward the dam safety program. Nevertheless, the section's civil engineer expressed concern abou t the ability of the ADNR to address important technical issues associated with dam safety, and the current regulations were again sharply criticized as inadequate. During the early 1980s, the ADNR (with support from consultants) conducted Phase I inspections and site visits of practically every dam that could be identified in the state, including those identified in the National Inventory of Darns. The USAGE listed 175 dams in Alaska in 1981. By 1984, the ADSP was staffed with three positions and a $350,000 general fund budget. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 2-1 Tier 10 Revisio n ! June 30, 2005 Attachment F Page 20 of 230 ED 002061 00172725-00020 Go to Table of Contents C hapter 2, Basis for Regulation of A laska Da m s In 1987, the state legislature passed the Alaska Dam Safety Act and AS 46.17, which elaborated on the basis for the state to "supervise" the safety of dams in Alaska. The state was required to employ a professional engineer for this purpose, but the staffing of the ADSP was reduced to that one individual and the budget was cut significantly. In 1989, the dam safety regula tions were again promulgated under Article 3 of 11 AAC 93. These statutes and regulations -were more comprehensive than previous versions, and were based on a model sta te dam safety program developed by the ASDSO and extensive review' of dam safety regulations from other states. The content of Article 3 of 11 AAC 93 was reviewed in detail and updated between 2000 and 2004. The regulations were revised to include important changes and clarifications about the hazard potential classification; dam owner's periodic safety inspections and emergency action plans; applications for construction, modification, repair, removal, and abandonment of dams; certificates of approval issued by the department; incident reporting; qualifications for dam design and inspection engineers; and other important information. The original publication of the Guidelines for Cooperation with the Alaska Darn Safety Program (September 2003) was based on a draft version of the revised regula tions. The current guidelines (June 2005) are revised to be consistent with the current, final version of the regulations adopted in October 2004. 2.2 Dam Safety Statutes and Regulations The current statutes and regulations are outlined and summarized in the subsections below, 2.2.1 Alaska Statutes "Supervision of Safety of Dams and Reservoirs" is the heading of AS 46.17. Each section of the chapter is briefly summarized below. Section 46.17.010, Purpose - Provides a statement of purpose for Chapter 17. Section 46.17.020, Administration and Staffing - Provides the ADNR with a professional engineer and other employees to supervise the safety of darns in Alaska. Also allows the ADNR to hire engineering consultants to assist in its duties. Section 46.17.030, Regulations and Orders - Allows the ADNR to adopt regulations and. i.ssue ord,ers. Section 46.17.040, Approval Required - Requires dam owners and opera tors to obtain approva l from the ADNR to operate existing dams or to construct new ones. | Exemptions for | Federal ODastmtflSs I FFeeddeerraallllyyaorwmneedd aanndd ooppeerraatteedd | ddaammss aanndd ddaammss rreegguullaatteedd bbyy | tthhee FFeeddeerraall EEnneerrggyy RReegguullaattoorryy | CCoommmmiissssiioonn aarree eexxeemmppttffrroomm | tthheeAAllaasskkaa ddaamm ssaaffeettyy | ssttaattuutteess aanndd rreegguullaattiioonnss.. \ DDaammss tthhaatt aarree ddeessiiggnneedd aanndd | ccoonnssttrruucctteedd bbyyffeeddeerraall j agencies and transferred to |I non-federal entities are not j eexxeemmpptt. . | _______________ 1 Section 46.17.050, Inspections - Requires the periodic inspection of dams and allows the ADNR to conduct the inspection and charge the costs to the darn owner or require the dam owner to conduct the inspection to the departmen t's standards using an approved, qualified engineer. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 2-2 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 21 of 230 ED 002061 00172725-00021 Go to Table of Contents C hapter 2. Basis for Regulation of A laska Da m s Section 46.17.060, Entry upon Property - Provides the ADNR access to inspect a darn or reservoir and related documents with either written notice or an administrative subpoena or under emergency conditions. Section 46.17.070, Determining Danger - Allows the ADNR to consider the engineering integrity of the existing or proposed darn or reservoir to determine if there is a current or future danger, and allows the ADNR to order a dam owner to mitigate the danger. Section 46.17.080, Injunction and Damages - Allows the ADNR, with the assistance of the attorney general, to seek an injunction and damages to enforce the dam safety statutes and regulations. Section 46.17.090, Judicial Review - Subjects a final action of the ADNR to a judicial review as provided in the Administrative Procedures Act (AS 44.62). Section 46.17.100, Other Government Agencies - Allows the ADNR to enter cooperative agreements with other government agencies to administer the chapter, with certain exceptions; exempts federally owned and operated dams and dams regulated by the Federal Energy Regulatory Commission (FERC) from the provisions of the chapter; and excludes any restrictions of the chapter on the powers of the Alaska Department of Environmental Conservation (ADEC) and the Alaska Department of Fish and Game (ADF&G). Section 46.17.110, Action Against the State for Damages - Limits action against tire state, its agents, and employees for damages in carrying out the provisions of the chapter. Section 46.17.120, Duties of the Owner - Excludes any relief to a dam owner for the duties or liabilities incident to owning and operating a dam or reservoir. Section 46.17.150, Penalties - Outlines violations related to the dam safety statutes and regulations that can result in a Class A misdemeanor. Section 46.17.120, Definitions - Provides definitions of select terminology. 2.2.2 Alaska Administrative Code Regulations governing dam safety are articulated in Article 3, Dam Safety, of 11 AAC 93. Brief summaries of the sections in Article 3 regulations follow. Section 93.151, Applicability - States that the regulations apply to all dams in Alaska, except dams owned or operated by the federal government or regulated by the FERC, and clarifies hazard potential classifications that cause a dam to fall under state jurisdiction, regardless of the geometry of the dam or reservoir. Section 93.153, Barrier Measurement - Specifies how dams are to be measured for determining regulatory jurisdiction. G uidelines for C ooperation with the A laska Da m S afety Program Sierra Club v. EPA 18cv3472 NDCA 2-3 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 22 of 230 ED 002061 00172725-00022 Go to Table of Contents C hapter 2, Basis for Regulation of A laska Da m s Section 93.157, Hazard ClassificationDefines three classifications of darns based on the potential danger to lives and property caused by the dam; requires the owner, upon request of the ADNR, to provide information for use in a review of the hazard potential classification and allows the owner to propose the hazard potential classification based on that information; and allows the ADNR to reject an owner's proposed classification for certain reasons, and assign a hazard potential classification based on readily available information. Section 93.159, Owner's Periodic Safety Inspection - Discusses the requirements for PSIs of dams based on the hazard potential classification, and allows the ADN R to order additional inspections, studies, or analyses; revoke a Certificate of Approval to Operate a Dam; or issue operation, maintenance, repair, shutdown, or removal orders, as necessary to protect life and property. Transfer of Dam Jurisdiction | For dams under state jurisdiction that are \ transferred to Federal Energy Regulatory | Commission (FERC) jurisdiction, Dam Safety | will yield jurisdiction to the FERC under the | following conditions: | The dam owner must submit a license | application to the FERC. | The FERC must provide a letter to the | A D N R stating its assumption of dam | safety regulatory responsibility. \ if a FERC license is not issued, Dam Safety | jurisdiction will return to the state. For | dams under FERC jurisdiction that are | transferred to the state, an application for | a Certificate o f Approval to Operate a Dam | is required. | Section 93.161, State Inspections - Outlines the conditions under which the ADNR may conduct inspections of darns and those under which ADNR may conduct the inspection and recover costs from the owner. Section 93.163, Emergency Remedial Action - Allows the ADNR to take actions necessary to protect life and property, and outlines the conditions under which such action would be taken. Section 93.164, Owner's Emergency Action Plan - Requires the owner of a Class I or II dam to develop an EAP, identifies required content of an EAP, requires revision of the plan at least every three years, and requires exercise of the plan on a frequency determined by the ADNR. Section 93.167, Certification of Dams Constructed Before May 31,1987 - Lists the requirements for obtaining certification for dams built before May 31,1987. Section 93.171, Dam Construction, Repair, or Modification - Lists the application requirements for obtaining a Certificate o f Approval to Construct a Dam for new dams or a Certificate of Approval to Repair or Modify a Dam for existing dams. Section 93.172, Dam Removal or Abandonment - Lists the application requirements for a Certificate of Approval to Remove or Abandon a Dam for existing dams, including mine tailings dams. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 2-4 Tier 10 Revision 1 June 3 0,2005 Attachment F Page 23 of 230 ED 002061 00172725-00023 Go to Table of Contents C hapter 2, Basis for Regulation of A laska Dam s Section 93.173, Certificates of Approval - Outlines the circumstances under which the department may issue, deny, or revoke a certificate of approval, as well as conditions and administrative requirements for the various certificates of approval issued by the ADNR. Section 93.175, Records - Lists the requirements for records to be kept by the owner of a dam. Section 93.177, Reporting of Dam Incidents - Requires the dam owner to report certain incidents involving the dam to the ADNR. Section 93.193, Qualified Engineers - Identifies the minimum qualifications of an engineer who can seal the following documents requiring ADNR approval: proposed hazard potential classifications, design engineering reports, design and construction drawings, construction specifications, construction completion reports, and other engineering documents. In addition, the qualifications of engineers who may be approved by the ADNR for conducting PSls are identified. Section 93.195, Inundation Maps and Inflow Design Flood Information - Lists requirements for the development of inundation maps and inflow design floods. Section 93.197, Operation and Maintenance Manuals - Identifies the requirements for the contents of an operation and maintenance manual, which is required for all dams. Section 93.201, Definitions - Provides definitions of select terminology. 2.3 Definition of a State Jurisdictional Dam To determine if a dam is under state jurisdiction, AS 46.17.900(3) defines a dam as an "artificial barrier and its appurtenant works, which may impound or divert water" and which meets at least one of the following three descriptions: "(A) Has or will have an impounding capacity at maximum water storage elevation of 50 acre-feet and is at least 10 feet in height measured from the lowest point at either the upstream or downstream toe of the dam to the crest of the dam." A dam with a jurisdictional height (H) of 10 feet or taller and that stores 50 acre-feet or more of water meets this description, as illustrated in Figure 2-1. "(B) Is at least 20 feet in height measured from the lowest point at either the upstream or downstream toe of the dam to the crest of the dam." A dam that is 20 feet or more in height meets this description regardless of its storage capacity, as illustrated in Figure 2-2. "(C) Poses a threat to lives and property as determined by the department after an inspection," In other words, a barrier with a Class I (high) or Class II (significant) hazard potential classification is considered a dam, even if it does not meet the geometric criteria of A or B, above. See Section 2.4 for guidance in determining the hazard potential classification. Guidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 2-5 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 24 of 230 ED 002061 00172725-00024 Go to Table of Contents C hapter 2, Basis for Regulation of A laska Da m s Figure 2-1, Jurisdictional Dam Based on Storage Capacity and Height Crest of Dam Figure 2-2. Jurisdictional Dam Based on Height Only Another guide for determining whether a dam is under state dam safety jurisdiction is illustrated in Figure 2-3. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 2-6 Tier 10 Revision 1 June 30, 2005 Attachment F Page 25 of 230 ED 002061 00172725-00025 Go to Table of Contents C hapter 2, Basis for Regulation of A laska Da m s Figure 2-3, Summary of Conditions for State Jurisdiction of a Dam >50 40 Is o 1 20 10 (I MMMMMMMM11 W W W W lllllll 0 10 20 30 40 00 00 70 80 00 >100 C a p a c ity facre-feeij Vegliateci if a Class l >r Cii&ss II Dam ReguSated due to Height or Storage Car<aei?y Additional clarification is provided in the regulations under 11 AAC 93.153, Barrier Measurement. This section clarifies how barriers are to be measured with respect to a watercourse and states: .. .the height of the harrier will be measured as either (1) the maximum vertical distance from the natural bed of tire watercourse at the upstream or downstream toe of the barrier, whichever yields the greater measurement, to the top of the barrier, or (2) if the barrier is not across a watercourse, the maximum vertical distance from the lowest elevation of the outside limit of the barrier to the top of the barrier. Water Supply Dams A reliable supply of water is critical to the health and econom y of a community. Primarily on the basis of experience with the Kake Dam failure in 2000, Dam Safety asserts that a community of 500 Figures 2-4 through 2-7 present graphical residents or more that depends on interpretations of this section. Figures 2-4 and 2-5 a dam for the primary water illustrate a section and profile, respectively, of a supply represents a risk sufficient typical, cross-valley dam. tojustify a Class II (significant) Figure 2-7 is intended to illustrate a saddle dam or auxiliary dike in a situation for which measurement from the top of the dam to the " upstream" toe could result in a dam height that is taller than the height of the "downstream" toe. Figure 2-6 illustrates a dam hazard potential classification of the dam, regardless of its geometry; therefore, such a dam and reservoir are under state dam safety jurisdiction. that is not located across a watercourse, such as a ring G u id e l in e s f o r C o o p e r a t io n w it h th e A laska D a m S afety Pro g ram Sierra Club v. E P A 18cv3472 N D C A 2-7 Tier 10 R e v isio n 1 June 3 0 , 2 0 0 5 Attachment F Page 26 of 230 ED 002061 00172725-00026 Go to Table of Contents C hapter 2, Basis for Regulation of A laska Da m s Figure 2-6. Ring Dike H = Elevation A - Elevation B Figure 2-7. Saddle Dam or Off-Stream Dam H = larger number If H-i > H2, then H = H-i If H2 > H-i, then H = H2 dike or a heap leach pad. In this case, the volume below original grade, or dead storage, would not he counted if 11 were between 10 and 20 feet and the volume calculation was required to determine jurisdiction. In all cases for which the volume calculation is required, the "maximum water storage elevation" is assumed to occur at the crest of the dam, as indicated in Figures 2-1 and 2-6, unless the spillway is sufficient to pass the design flood (defined later in these guidelines). In this case, G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 2-8 Tier 10 Revision 1 June 30, 2005 Attachment F Page 27 of 230 ED 002061 00172725-00027 Go to Table of Contents C hapter 2. Basis for Regulation of A laska Dam s the volume should be calculated at the elevation of the maximum stage during the flood. The height of the darn would still be measured to the crest of the dam to include freeboard. If a dam is to be used for storing substances other than dean water, such as sewage, sludge, or mine tailings, but which still have the ability to flow similarly to water under certain conditions, the principles outlined above still apply. If the failure of the dam could result in the release of substances that could create a significant danger or risk to public health, that dam will be considered at least a Class II (significant) hazard dam. To reach agreement on which dams meet the sta tutory definition of a dam and, therefore, fall under the jurisdiction of the ADSP, Dam Safety developed the Hazard Potential Classification and jurisdictional Review Form presented in Appendix A. Additional information about the hazard potential classification is presented in the following section, and darn failure analysis is presented in Section 9.3. 2.4 Hazard Potential Classification The hazard potential classification is the main parameter for determining the level of attention that a dam requires throughout the life of the project, from conception to removal. The hazard potential classification represents the basis for the scope of the design and construction effort, and dictates the requirements for certain inspections and emergency planning. The ADSP uses three classifications for dams based on the potential impacts of failure or improper operation of a dam: Class 1(high) Class II (significant) Class 111 (low) The hazard potential classifications are explained in detail in 11 AAC 93.157 and are summarized in Table 2-1. Dams are classified based on theoretical estimates of the potential impact to human life and property if the dam were to fail in a manner that is typical for the type of darn under review, or if improper operation of the dam could result in adverse impacts. The actual or perceived quality of design and construction and the condition of the dam are irrelevant for the classification, but may influence other requirements such as the frequency of monitoring, the scope of PSIs, and the content of O&M manuals and EAPs. To determine the hazard potential classification consistently and equitably for projects, Dam Safety developed the Hazard Potential Classification and Jurisdictional Review Form in Appendix A, as previously mentioned. This form should he completed by a qualified engineer based on the existing or proposed configuration of the dam, and submitted to Dam Safety for review and concurrence. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 2-9 Tier 10 Revision 1 June 3 0,2005 Attachment F Page 28 of 230 ED 002061 00172725-00028 Go to Table of Contents C hapter 2, Basis for Regulation of A laska Dam s Table 2-1, Hazard Potential Classification Summary Hazard C lass ! (High) !i (Significant) E ffect on H um an Life Probable loss of one or more lives No loss of life expected, although a significant danger to public health may exist III (Low) insignificant danger to public health Effect on Property irrelevant for classification, but may include the same tosses indicated in Class II or III Probable loss of or significant damage to homes, occupied structures, commercial or high-value property, major highways, primary roads, railroads, or public utilities, or other significant property losses or damage not limited to the owner of the barrier Probable loss of or significant damage to waters identified under 11 AAC 195.010(a) as important for spawning, rearing, or migration of anadromous fish Limited impact to rural or undeveloped land, rural or secondary roads, and structures Loss or damage of property limited to the owner of the barrier The form presented in Appendix A is designed as a "tickler" to remind the engineer of important aspects that should be considered in the review. In addition, the form is designed to be progressive. Three levels of review are available: Preliminary - An initial, conservative assignment based on a visual inspection of the dam, the reservoir, the downstream reach, and other limited, readily available information such as aerial photography and topographic maps Qualitative - A limited engineering evaluation that may involve crude hydrological estima tes, simplistic peak discharge calculations for a dam failure or mis-operation, open-channel flow calculations, elevation or cross-section surveys, and simplistic data used with conservative assumptions Quantitative - A detailed dam failure analysis that includes failure mode evaluation, compu terized dam-break and hydraulicrouting models, detailed hydrological estimates, and good-quality input data Potential Future Development and Hazard Potential Classification A h a zard potential classification determines the standard for the design, construction, and operation of the dam during the life of the project. If additional downstream development is likely, the dam should be designed and constructed to standards for the higher classification, although the dam may be classified and managed for existing conditions until the future development occurs. The higher levels of analyses and detail carry more credibility in the assignment of the classification. For example, a preliminary assignment of a Class II (significant) hazard potential could be overruled if a qualitative or quantitative review demonstrates that the potential for adverse impacts is actually low. In another example, if neve development occurs below an existing Class III (low) hazard dam, a qualitative analysis may be used to upgrade the dam to a Class I (high) hazard, whereas a quantitative analysis may demonstrate that a Class II G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 2-10 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 29 of 230 ED 002061 00172725-00029 Go to Table of Contents C hapter 2. Basis for Regulation of A laska Da m s (significant) hazard is the appropriate classification. Additional information about dam failure analysis is presented in Section 9.3. The ADSP hazard potential classifications were modified in the current regulations to he consistent with guidance contained in the following source: Federal Guidelines for Dam. Safety: Hazard Potential Classification System for Dams, published by the Federal Emergency Management Agency (1998b) Admittedly, much of the terminology used in 11 AAC 93.157 is not specific; for example, "probable" is not currently defined. Dam Safety will consider arguments presented by dam owners for hazard potential classifications that are in dispute, including risk assessments that quantitatively assign probabilities to certain outcomes. Nevertheless, those arguments should be cooperatively developed, technically sound, and justifiable. Additional information about risk assessments is presented in Section 12.3. The following references may also he helpful in assigning the hazard potential classification: Evaluation Procedures for Hydrologic Safety of Dams, published by the American Society of Civil Engineers (1988) "Dam Break inundation Analysis and Downstream Hazard Classification," Technical Note 1, in Dam Safety Guidelines, published by the Washington State Department of Ecology (WSDOE) (1992) 2.5 Associated Permits and Regulatory Agencies This publication provides guidance only for the permits and submittals associated with the ADSP. In addition to the design and construction submittals discussed in Chapter 5, only the following information is required by 11 AAC 93.171 before Dam Safety will issue a Certificate of Approval to Construct a Dam: For dams and reservoirs to be located partially or completely on property not owned by the dam owner, the property owners must provide legal permission to construct the dam or reservoir. A copy of the land use permit must be provided to Dam Safety. Proof of a water right or wa ter right application, as required by AS 46.15. Coordination of Permits Dam Safety will not typically withhold a certificate of approval pending coordination with or conditional to any other permits that m ay he required from local, state, or federal agencies. However, those other permits m ay he required before construction can actually occur. Dam Safety will work within the framework of the Alaska Department of Natural Resources Large Mines Project Team and the Alaska Coastal Management Program for associated projects that include dams. Coordination of permits for other projects is the responsibility of the applicant. Guidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 2-1 1 Tier 10 Revision 1 June 30, 2005 Attachment F Page 30 of 230 ED 002061 00172725-00030 Go to Table of Contents C hapter 2, Basis for Regulation of A laska Da m s The owner of the dam is ultimately responsible for securing all permits necessary for the construction and operation of the dam. The following state and federal agencies should be contacted for more information: Local municipality or borough Alaska Department of Natural Resources Alaska Department of Environmental Conservation Alaska Department of Fish and Game State Historic Preservation Office U.S. Army Corps of Engineers U.S. Environmental Protection Agency The following is a useful reference for federal permitting associated with dams: Environmental Permittingfor Dam Projects (1996), published by the ASDSO G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 2-12 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 31 of 230 ED 002061 00172725-00031 Go to I'able of Contents Guidelines for Cooperation with the Alaska Dam Safety Program Chapter 3 CERTIFICATES OF APPROVAL 3.1 Operation.................................................................................................................................3-1 3.2 Construction........................................................................................................................... 3-2 3.3 Applications for Certificates of Approval.......................................................................... 3-3 3.4 Application Fee...................................................................................................................... 3-4 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 32 of 230 ED 002061 00172725-00032 Go to Table of Contents Chapter 3 C E illF lC T E S OF APPROVAL In this chapter: > The certificates of approval issued by Dam Safety > Policies and procedures of Dam Safety for applications and issuing certificates > Application and fee information Permits issued by Dam Safety under 11 AAC 93 are referred to as "certificates of approval" for a particular activity. These certificates are required for routine operation of a dam and certain construction activities related to the dam. A separate certificate is required for each of the following actions: Operation Construction Modification Repair Removal Abandonment Additional information on these certificates is provided in the following sections. 3.1 Operation Certificate o f A p p ro v a l to Operate a Dam - This permit is required for all jurisdictional darns in service as of May 31,1987, and all jurisdictional dams constructed after that date. To receive a C ertificate o f A pproval to O perate a D am , the following information must be submitted to Dam Safety for review and approval: Operations and maintenance manual Current PSI report Record drawings EAP for Class I and II dams Construction completion report for new construction GUIDELINES FOR COOPERATION WITH the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 3-1 Tier 10 REVISION 1 June 30, 2005 Attachment F Page 33 of 230 ED 002061 00172725-00033 Go to Table of Contents C hapter 3. C ertificates of A pproval The Certificate of Approval to Operate a Dam is dated to expire after each PSI and is typically reissued after the PSI report is completed and approved. The expiration date may be extended when a PSI report is submitted for review. The O&M manual and the EAP may also require updating before a current certificate will be issued. Additional information about the required documents is presented in subsequent sections of these guidelines. For new construction, major modifications or repair, a new Certificate of Approval to Operate a Dam. is typically required before the reservoir may be filled or additional impoundmen t may occur above the level currently permitted. Additional information about construction-related certificates is included in the following section. All Certificates o f Approval to Operate a Dam include standard conditions, and special conditions are noted in Attachment A of the certificate. The special conditions typically include the hazard potential classification and the due date of the next PSI. They may also include operating limitations and other restrictions or requirements unique to the dam and its appurtenances. A sample of a Certificate o f Approval to Operate a Dam is presented in Appendix B. 3.2 Construction Certificate o f Approval to Construct a Dam ~ This permit is required to build a new jurisdictional dam. C ertiJfica te ojf A pmp ro v a l to M o d ijfjy a D a m - This fpermit is reqnuired for a modification on a }jurisdictional dam. Defined in 11 AAC 93.201(8), modification refers to an "enlargement or alteration' that may affect the safety of the dam. E,xamples include. raising; the h. eight,of the dam, in,creasing the storage capacity, or changing valves on an outlet pipe. Breach of Conditional | Approvals | A.n y b, reach, es or d.evi.at..ions 1\ f,frroomm tthhee ccoonnddi.it.t.i.ioonnss of annyy |1 cceerrttiiffiiccaattee ooffaapppprroovvaall mmuusstt^ | ( ,be reported, to and, | t , , ,, . approved by Dam Safety in tI wwrriittiinngg. Certificate o f A pproval to Repair a Dam. - This permit is | required to repair a jurisdictional dam. Repair is defined in both AS 46.17.900(8) and 11 AAC 93.201(11) as a repair that could affect the safety of the dam, but excludes routine maintenance. Repair in this sense could include slip-lining a low-level outlet, rebuilding the spillway, or repairing an overtopped or breached dam. Certificate o f A pproval to Remove a Dam - This permit is required to remove a jurisdictional darn. Certificate o f Approval to Abandon a Dam - This permit is required to abandon a jurisdictional dam iti place without removing the structure of the dam. These certificates also include standard conditions, and special conditions are noted in Attachment A of the certificate. Special conditions may include desigli and construction restrictions, construction quality assurance requirements, post-construction monitoring and inspection requirements, or other important conditions. A sample of a Certificate o f Approval to Construct a Dam is presented in Appendix C. A signed, certificate of approval must be issued by Dam Safety before the construction, modification, repair, removal, or abandonment begins. Guidelines for C ooperation with the A laska Dam Safety Program Sierra Club v. E P A 18cv3472 N D C A 3-2 Tier 10 Revision 1 June 3 0 ,2005 Attachment F Page 34 of 230 ED 002061 00172725-00034 Go to Table of Contents C hapter 3. C ertificates of A pproval 3.3 Applications for Certificates of Approval The application process provides an opportunity for communication between Dam Safety and the applicant. This communication should begin early in the project planning because the process can become extended and complicated, depending on the magnitude and complexity of the project. A number of submittals must be made to Dam Safety for review to receive a certificate of approval. Dam Safety will comment on the submittals during the application process to promote dialogue and understanding of the project. A certificate of approval is issued at the end of the review period as appropriate. The remainder of the information provided in this section highlights specific policies and procedures of Dam Safety that are intended to establish consistency with respect to which certificates require applications and how certificates are issued. Chapter 4 presents a detailed outline of a hypothetical sequence of the regulatory process during the life of a dam to allow all parties involved to plan effectively. Applications for Dams Built Before 1987 An application for a Certificate of Approval to Operate a Dam and fee is only required for darns built before May 31,1987, that are not registered with Dam Safety. The in forma tion listed in Section 3.1 that must accompany an applica tion is described in additional detail in subsequent sections. An application and fee are required for all certificates listed in Section 3.2, regardless of the original construction date, except for the construction certificate. Applications for All Other Dams A specific application for a Certificate o f A pproval to Operate a Dam is not required for darns built after May 31,1987, that received a Certificate ofApproval to Construct a Dam. An application and fee are required for all certificates listed in Section 3.2. For new dam construction, a Certificate of Approval to Operate a Darn will be issued after post-construction submittals are reviewed and approved by Darn Safety. For existing dams that are repaired or modified, post construction submittals are also required, and the Certificate o f A pproval to Operate a Dam may be reissued with revised special conditions. A PS1 may be required after the first year of operation for new dams or for dams with major modifications or repairs. O&M plans and EAPs must be revised as appropriate for dams with major modifications or repairs. Dams Without | Construction Certification | If a dam was built after | May 3 1 , 1 9 8 7 , without a | Certificate of Approval to | Construct a Dam, the | special circu m sta n ce m u st | b e reso lv ed individually with \ Dam Safety. | G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 3-3 Tier 10 Re v is io n ] June 30, 2005 Attachment F Page 35 of 230 ED 002061 00172725-00035 Go to Table of Contents C hapter 3. C ertificates of A pproval Issuance of Certificates of Approval Dam Safety will issue a draft certificate of approval in a spirit of cooperation to give the dam owner or operator the opportunity to comment and agree on the conditions of the permi t. After an agreement is reached, a final certificate is executed and sent by certified mail to the applicant. In some cases, a final certificate may be issued without agreement; for example, a certificate may include a condition imposed by Dam Safety that the operator feels is especially onerous. In any case, a final, formally executed certificate issued by Dam Safety carries the full weight and authority of the ADNR under the dam safety statutes and regulations. Appeals may be filed with the commissioner of ADNR in accordance with 11 AAC 02. 3.4 Application Fee The permit application requires a nonrefundable filing fee, as described below and in 11 AAC 05.010(a)(8)(I and ]). Additional detail about the fees follows. Certificate o f Approval to Operate a Dam According to 11 AAC 05.010(a)(8)(I), for a dam constructed before May 31,1987, the fee is based on the height of the darn (as defined in Section 2.3), multiplied by $50 per foot. Certificate o f A pproval to Construct, Modify, Repair, Remove, or Abandon a Dam - According to 11 AAC 05.010(a)(8)(J), the fee is based on a scale of the estimated project cost. A non-refundable deposit on the application fee, which is based on estimated costs, is required with the initial Application Package, as described in Section 5.1.3. An application fee supplement based on a certified cost estimate is required with the Final Construction Package, as described in Section 5.4.4, before a final certificate of approval will be issued. Planning for the Application and Review Dam Safety established the submittal packages a n d review tim es show n in C h a p ter 4 as ta rg ets to allow d a m ow ners a n d operators to plan effectively. However, every dam is unique and deviations and delays m ay be req u ired fo r a variety o f reasons. T he o bjectives o f D am S a fety a re to c o n d u c t the re v ie w in th e m o s t exp ed itio u s m a n n e r po ssible to m eet the p ro ject sch ed u le, without com prom ising the m ission o f the ADSP. C onsistency and c o n fo rm a n c e with the s u g g e s t e d a p p r o a c h will h e lp a c c o m p lis h this objective. The minimum fee is $500, which applies to projects that are estimated to cost less than or equal to $25,000. If the project is expected to cost more than $25,000, Table 3-1 should be used to calculate the application fee. According to 11 AAC 93.171(f)(4)(D), the estimated cost of the project must include the following: Labor and materials for the construction of the dam, reservoir, and appurtenant works Site investigations, which include geological and geotechnical investigations and laboratory testing Engineering and surveying Guidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 3-4 Tier 10 Revision 1 June 30, 2005 Attachment F Page 36 of 230 ED 002061 00172725-00036 Ci to Table of Contents C hapter 3, C ertificates of A pproval Construction supervision and quality assurance Other direct costs associated with the design and construction activities Table 3-1. Application Fee Calculation Portion o f P roject C ost The first $100,000 The next $400,000 The next $500,000 Balance of cost Total project cost: Project C ost A m ount $ $ $ $ $ M ultiplier 0.02 0.01 0.005 0.0025 Total Fee: Fee Am ount S $ $ $ $ G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 3-5 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 37 of 230 ED 002061 00172725-00037 Go to Table of Contents C hapter 3, C ertificates of A pproval G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 3-6 Tier 10 Revision 1 June 3 0 ,2005 Attachment F Page 38 of 230 ED 002061 00172725-00038 Go to Table of Contents Guidelines for Cooperation with the --- Alaska Dam Safety Program Chapter 4 FIVE STAGES IN THE REGULATORY LIFE 4.1 Application for New Dam Construction............................................................................ 4-1 4.2 Construction ............. 4-4 4.3 Operation................................................................................................................................ 4-4 4.4 Remediation.................. 4-6 4.5 Closure..................................................................................................................................... 4-6 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 39 of 230 ED 002061 00172725-00039 Go to Table of Contents Chapter 4 FIVE STAGES IN THE REGULATORY UFE OF A DAM In this chapter: > The five stages in the regulatory life o f a dam > A list of regulatory requirements that occur in each stage of the d am 's life > The regulatory review process for design, construction, and operation This section identifies the types of information that are exchanged during the regulatory life of a hypothetical dam and the point in time at which the exchange typically occurs. For presentation purposes, the life of the dam is divided into five stages: Applica tion for new dam construc tion Construction Operation Remediation Closure The following sections present key aspects of each stage with respect to submittals to Dam Safety that are typically required, as well as other important considerations. For the first three stages, the exchange of information between the various parties cooperating in the overall safety of the dam is graphically illustrated in the form of a schedule. The remainder of the guidelines present additional detailed information related to this section. Application Requirements for Existing Dams The application requ irem en ts d is c u s s e d in S ectio n 4 .7 c o v e r a complete application p ro cess, n eed ed fo r construction o f a new dam, to provide the g re a te s t detail. Som e inform ation outlined h e r e m a y not he re q u ire d w hen the activity consists o f rep a ir or m odification o f an existing dam . 4.1 Application for New Dam Construction To receive a certificate of approval listed in Section 3.2, an application must be submitted to Dam Safety. As indicated in 11 AAC 93.171, the application must include a substantial amount of technical information. Dam Safety requests that the application process occur in the increments listed below. The items to be included with each incremental submittal are indicated. Additional detail is provided in subsequent sections. Figure 4-1 illustrates a suggested permitting process for new construction. G UID ELIN ES FOR C O O PERATIO N WITH the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 4-1 Tier 10 Revision 1 June 3 0 ,2005 Attachment F Page 40 of 230 ED 002061 00172725-00040 Sierra Club v. E P A 18cv3472 N D C A C hapter 4. Five Stages in the Regulatory Life of a Dam ID TasK Name 1 initial Application Package 2* Project meeting, Dam Safety review and response 6 Investigations, planning and preliminary engineering I Duration Year 1 Yes W TMJW TW Tm TW TW TW TW TW m M uTm Tiim im iiW zW W Tm fTm W l 1 day 30 days 'A i i 30 days Go tH'Fable of Contents 120 days? 4 P relim inary Design P ackage 1 day Dam Safety review and response 60 days 6 Oetasied design engineering 48 days? I ? Detailed Design Package 1 day 8 Dam Safety review and response, issue draft Certificate o f Approval to Constructs Dam 9 Final design engineering 60 disys 30 days? 10 F in al C o n stru ctio n P ackag e 11 Dam Safety review and response 1 day 30 days 12 Final Certificate o f Approval to 1 day Comtmct a Dam Project: N E W B IG DAW D/F:DamSe1ety lR.mpp i Dam Safety target review period Dam Safety rexpense Applicant dapaderst period Prior effort at applicant' risk Suggested project Odd point | Submittal milestone ^ Project meeting (} Desired outcome Hi i days I Lh l Figure 4-1, Dam Safety Application Review Process Italic font indicates action by Dam Safety. B old fo n t indicates submittals from applicant or permits from agency. Tier 10 Attachment F Page 41 of 230 ED 002061 00172725-00i G uidelines for C ooperation with 4-2 T he A laska Dam Safety Program o -i^ Revision 1 June 30, 2005 Go to Table of Contents C hapter 4. Five Stages in the Regulatory Life of a D am Initial Application Package (See Section 5.1.) Letter of intent (See Subsection 5.1.1.) Application form (See Subsection 5.1.2 and Section 3.3.) Application fee deposit (See Subsection 5.1.3 and Section 3.4.) Proposed schedule (See Subsection 5.1.4.) Hazard Potential Classification and Jurisdictional Review Form (See Sections 2.4 and 9.3, Subsection 5.1.5, and Appendix A.) Feasibility and siting studies for new construction of Class I and II darns (See Subsection 5.1.6.) Design scope proposal (See Subsection 5.1.7.) Striving for Simplicity The complexity of the application process is expected to reflect the h a za rd potential classification of the dam and the complexity of the work for which approval is required. The objective of this submittal outline is to simplify the process as much as possible for every project while promoting the standard of care appropriate for the hazard potential classification of the dam. Preliminary Design Package (See Section 5.2.) Proof of water and land use rights (See Section 2.5 and Subsection 5.2.1.) Proposed method to demonstrate financial ability to pay for certain costs (See Section 5.2.2) Topographic map of the dam site (See Subsection 5.2.3.) Preliminary drawings (See Subsection 5.2.4.) Engineering science reports (See Subsection 5.2.5.) Recused proposed schedule (See Subsection 5.2.6.) Detailed Design Package (See Section 5.3.) Engineering design report (See Subsection 5.3.1.) Design drawings (See Subsection 5.3.2.) Draft construction specifications (See Subsection 5.3.3.) Construction quality assurance/quality control (CQA/QC) plan (See Subsection 5.3.4 and Section 7.2.) Revised proposed schedule (See Subsection 5.3.5.) Final Construction Package (See Section 5.4.) Final construction drawings (See Subsection 5.4.1.) Final construction specifications (See Subsection 5.4.3.) G u id e l in e s f o r C o o p e r a t io n w it h the A laska D a m Safety Pro g ram Sierra Club v. E P A 18cv3472 N D C A 4-3 Tier 10 R e v isio n 1 June 3 0 ,2 0 0 5 Attachment F Page 42 of 230 ED 002061 00172725-00042 Go to Table of Contents C hapter 4. Five Stages i n the Regulatory Life of a D am Construction schedule (See Subsection 5.4.5.) Certified cost estimate (See Subsection 5.4.4.) Application fee supplement, if required (See Subsection 5.4.5.) Demonstration of financial ability (See Subsection 5.4.6.) 4.2 Construction Construction of the new dam or the repair or modification of an existing dam may begin only after Darn Safety issues the appropriate certificate of approval. In some cases, certain preconstruction documents may be listed as a condition to the certificate, and the submittal will be required before construction actually begins. Required by 11 AAC 93.171, these documents are usually prepared by the contractor, but can have an important effect on the mission of the ADNR and the safety of the dam. Additionally, cooperation and communication are required during the construction process, and post-construction submittals are critical to receive the C ertificate o f A pproval to O perate a D am . Figure 4-2 illustrates the regulatory review during the construction process, which is outlined below and discussed in additional detail in Chapter 7. Before construction, the following additional submittals to Dam Safety are typically required: Water diversion plan (See Subsection 7.1.1.) Erosion control plan (See Subsection 7.1.2.) During construction, the following activities typically occur: CQA/QC monitoring, field testing, sample collection, and laboratory testing (See Section 7.2.) Design changes that require approval by Dam Safety (See Subsection 7.2.4.) m Field inspections conducted by Dam Safety (See Section 10.5.) A fte r construction, the following submittals are required: Construction completion report that includes record drawings, inspection reports, photographs, and other information (See Subsection 7.3.1.) Operation and maintenance manual (See Subsection 7.3.3 and Chapter 8.) EAR for Class I and II dams (See Subsection 7.3.4 and Chapter 9.) G u id e l in e s f o r C o o p e r a t io n w it h th e A laska D a m Safety Pr o g ra m Sierra Club v. E P A 18cv3472 N D C A 4 -4 Tier 10 R e v isio n 1 June 30, 2005 Attachment F Page 43 of 230 ED 002061 00172725-00043 UJ Orr> Sierra Club v. EPA 18cv3472 NDCA Tier 10 uo 4* Oc yy&uOuL** CUCDQ) 56 '&>& 'iousP *iy0oo**c U >, \/S\ 2: O(j Em G rx*. 0<0r fsi 4' U d< < u 1 Attachment F Page 44 of 230 ED 002061 00172725-00044 Go to Table of Contents C hapter 4. Five Stages in the Regulatory Life of a D am 4.3 Operation After the post-construction submittals previously listed are reviewed and approved, Dam Safety will issue a new Certificate of Approval to Operate a Dam. The activities listed below are then expected to occur: First fill of reservoir and temporary monitoring (See Section 7.3.) Routine operations, inspections, monitoring, and maintenance (See Chapters 8 and 10.) EAP exercises (See Chapter 9.) PSIs (See Section 10.4.) Recurrent Certification and Revision During Operation A new Certificate o f Approval to Operate a Dam is issued after each PSI, with revised special conditions as appropriate. O&M manuals are revised as needed and reviewed during the PSI cycle. EAPs are reviewed during the exercise process, and revised as needed. Incident reporting (See Chapter 11.) Figure 4-3 illustrates the regulatory life of the dam during the first year of the operational stage, with emphasis on the PSI and references to subsequent years of operation. 4.4 Remediation After a period of time, a dam may require remedial efforts for a number of reasons, including deterioration, damage, or hazard potential classification change (which could affect the design basis). In some cases, typically for older dams, the need for remediation may be due to an inadequate design aspect that is discovered and determined to represent a sufficient risk to justify remedial action. The following activities are likely to occur: Assessment of need (See Section 10.4 and Chapter 12.) Design and construction of the solution At this point, the regulatory life of the dam may loop back to Sections 4.1 (except that the application is for a Certificate of Approval to Modify, or Repair a Dam), 4.2, and 4.3, or proceed to Section 4.5. 4.5 Closure Closure of a dam and reservoir may occur for a number of reasons and may result in one of the following actions, either of which requires an application for a certificate of approval: Removal Abandonment Details for these options are presented in Chapter 13. Guidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 4-6 Tier 10 Revision 1 June 30, 2005 Attachment F Page 45 of 230 ED 002061 00172725-00045 Sierra Club v. E P A 18cv3472 N D C A C hapter 4. Five Stages in the Regulatory Life of a Dam Tier 10 Attachment F Page 46 of 230 ED 002061 00172725-00046 Figure 4-3, Dam Safety Operations Review Process Italic font indicates action by Dam Safety. Bold font indicates submittals from applicant or permits from agency. G uidelines for C ooperation with 4-7 T he A laska Dam Safety Program Revision 1 June 30, 2005 Go to Table of Contents \ C hapter 4. Five Stages in the Regulatory Life of a D am G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 4-8 Tier 10 Revision 1 June 30, 2005 Attachment F Page 47 of 230 ED 002061 00172725-00047 Go to Table of Contents Guidelines for Cooperation with the Alaska Dam Safety Program Chapter 5 CONSTRUCTION APPLICATION DETAILS 5.1 Initial Application Package.................................................................................................. 5-1 5.1.1 Letter of Intent........................................................................................................... 5-2 5.1.2 Application Form......................................................................................................... 5-3 5.1.3 Application Fee Deposit.............................................................................................. 5-3 5.1.4 Proposed Schedule......... .............................................................................................5-3 5.1.5 Hazard Potential Classification.................................................................................. 5-3 5.1.6 Feasibility and Siting Studies........... ......................................................................... 5-4 5.1.7 Design Scope Proposal................................................................................................. 5-6 5.2 Preliminary Design Package................................................................................................ 5-5 5.2.1 Water and Land Use Rights.......................................................................................5-7 5.2.2 Proposed Financial Demonstration........................................................................... 5-7 5.2.3 Topographic Map of Dam Site................................................................................... 5-8 5.2.4 Preliminary Drawings ............................................................................................... 5-9 5.2.5 Engineering- Science Reports....................................................................................... 5-9 5.2.6 Revised Proposed Schedule....... ........................................................................ 5-10 5.3 Detailed Design Package..................................................................................................... 5-10 5.3.1 Engineering Design Report....................................................................................... 5-11 5.3.2 Design Drawings..................................................................................................... 5-11 5.3.3 Draft Construction Specifications............................................................................ 5-12 5.3.4 Construction Quality Assurance/ Quality Control Plan....................................... 5-12 5.3.5 Revised Proposed Schedule....... ......................................................................... 5-13 5.4 Final Construction Package................................................................................................ 5-13 5.4.1 Final Construction Drawings.......... ........................................................................ 5-13 5.4.2 Final Construction Specifications............................................................................. 5-14 5.4.3 Construction Schedule............................................................................................... 5-14 5.4.4 Certified Cost Estimate.............. ......................................................................... 5-14 5.4.5 Application Fee Supplement.................................................................................... 5-12 5.4.6 Demonstration of Financial Ability......................................................................... 5-15 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 48 of 230 ED 002061 00172725-00048 Ci to Table of Contents Chapter 5 CONSTRUCTION APPLICATION DETAILS In this chapter: > Detailed description of the requirements for construction of a new dam and repair and modification of an existing dam > Outlines of the contents of submittals that accompany an application > Standards for submittals The following sections provide details about the preferred development, format, and presentation of various types of information usually considered in the application process for a Certificate of Approval to Construct a Dam. Much of the information also applies to repairs or, modifications of dams, and the submittals to Dam Safety should be modified as appropriate. Not all of the information may be required. Because every project is unique, it is impossible to anticipate and outline all design and construction issues that may arise in a generic format. Consequently, the following information is intended to encourage communication and agreement early in the planning process to limit costly revisions and delays. Figure 5-1 illustrates the incentive for accomplishing these objectives. The design and analysis of a dam consists of extensive technical work. The presentation of this work will reflect the quality of the entire project. Engineering reports should clearly document the methodology, assumptions, parameters, calculations, computer programs, references, results, engineering judgmen t, and recommenda tions used in the evalua tion process. Drawings should contain the definition and detail necessary to relay critical information for permitting and construction. Poor quality or incomplete submittals may be rejected. The following sections discuss important aspects of the information developed in the construction application process and the preferred standards for submittals to Dam Safety. 5.1 Initial Application Package The Initial Application Package submitted to Dam Safety is the first step in the application process and is intended to establish agreement on important information early in the project planning. Detailed guidelines for certain submittals that should be included in the Initial Application Package are presented in the following subsections. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 5- Tier 10 Revision I June 30, 2005 Attachment F Page 49 of 230 ED 002061 00172725-00049 Go to Table of Contents C hapter 5, C onstruction A pplication D etails Figure 5-1. Relative Cost-to-Change Curve Adapted from A S D S O , 2003 f!1l&iil Letter cilf iiulteifilt A letter that introduces the project arid includes the following information is requested to notify Dam Safety of the applicant's intent: Description of the proposed project or work to be completed under the anticipated certificate of approval identity of the applicant and contact information Identity of the dam owner and operator, if other than the applicant Identity and qualifications of the engineer of record responsible for certifying the design, (See Subsection 1.3,4.) For complex projects, an engineering team comprised of more than one engineer of record may be required for the design. In those cases, all engineers of record should be included. A list of attachments G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 5-2 Tier 10 Revision 1 June 3 0,2005 Attachment F Page 50 of 230 ED 002061 00172725-00050 Go to Table of Contents C hapter 5. C onstruction A pplication D etails 5.1.2 Application Form The most current application form available from Dam Safety should be used. The most current form may be downloaded from www.dnr.state.ak.us/m lw/form s/. The application must be signed by tire owner of the dam. Any technical information requested on the form may be based on the conceptual design for new construction or existing or proposed values for all other applications. 5.1.3 Application Fee Deposit A preliminary cost estimate developed by the applicant may be used to calculate the nonrefundable fee deposit, as indicated in Section 3.4 and Table 3-1. The fee deposit should be included with the Initial Application Package. The check should be made payable to the "State of Alaska" and submitted with the application to Dam Safety. For fees that exceed $2,000, the fee may be considered a statutory designated program receipt, and all expenses by the ADNR related to the project will be billed to the respective account. 5.1.4 Proposed Schedule A proposed schedule that shows the approximate dates for the following should be submitted with the Initial Application Package: Preliminary Design Package submittal (See Section 5.2.) Detailed Design Package submittal (See Section 5.3.) Final Construction Package submittal (See Section 5.4.) Beginning of construction The proposed schedule should allow for the Dam Safety target review times indicated in Figure 4.1. Dam Safety will coopera te as much as possible to accommodate the proposed schedule. 5.1.5 Hazard Potential Classification Early agreement on the hazard potential classification of a dam is imperative to conserve the design and investigation budgets. A Hazard Potential Classification and Jurisdictional Reviewr Form, described in Section 2.4, should be completed for the proposed dam and included with the Initial Application Package. In some cases, a qualitative or quantitative evaluation may be required, even if the dam is in the preliminary stages of planning. For example, if some development exists downstream of the proposed dam site, a Class III (low) hazard potential classification may not be approved by Dam Safety unless a technical demonstration is made to show that the flood wave from a failure G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 5-3 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 51 of 230 ED 002061 00172725-00051 Go to Table of Contents C hapter 5. C onstruction A pplication D etails of the conceptual dam is attenuated or inconsequential to the existing development as well as to any potential future development that may be reasonably anticipated. For the Initial Application Package, the level of the evaluation for the hazard potential classification should be in accordance with the guidance in Table 5-1. Not all situations may he addressed in the table. In addition, a more detaed evaluation may be required after final design for complex systems or to develop an EAP. Additional information on dam failure analysis is provided in Section 9.3. Dam Safety should be contacted for specific guidance. Table 5-1. Acceptable Levels of Evaluation for Proposed Hazard Potential Classifications Proposed C lass ill (low) ill (low) II (significant) il (significant) I (high) i (high) Dam T ype and Location D escription of Dow nstream System Any rural water dam No development Any rural water dam Limited or heavy existing development or high potential for development Any dam located on an important salmon stream, at a primary water supply for a community with more than 500 residents, or for retention of mine tailings No residential development Any dam in a rural or urban setting Limited or heavy existing residential development or high potential for development Any dam in a rural or urban setting Limited or heavy development or high potential for development Any dam with a large impoundment in a rural or urban setting Complex system with development in extended downstream reach A cceptable Level o f Evaluation Preliminary Qualitative or quantitative Preliminary Qualitative or quantitative Preliminary Quantitative 5.1.6 Feasibility and Siting Studies Feasibility and siting studies are required under 11 AAC 93.171 for new construction of Class I and II darns. These studies typically occur early in the planning process, often well in advance of the application for a certificate of approval. Feasibility Study To obtain a Certificate o fApproval to Construct a Dam for a Class I or II dam, a feasibility study that justifies the risks created by the dam is requested. The following general guidelines are recommended: At least four alternatives, including the no-action alternative, should be considered. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 5-4 Tier 10 Revision 1 June 3 0 ,2005 Attachment F Page 52 of 230 ED 002061 00172725-00052 Go to Table of Contents C hapter 5, C onstruction A pplication D etails At least one alternative should include a lower hazard potential classification dam or an alternative that does not require a darn. A Class I dam alternative should include the potential economic and lethal impacts of a dam failure in the analysis. ] ustification for the Class 1 dam alternative must not be based on inaccurate data, false assumptions, exaggerated importance, speculation, or baseless information. The benefit-to-cost ratio for the Class I dam alternative should be greater than one and exceed the other alternatives. Applications for a Certificate of Approval to Construct a Dam for a Class 1or 11 dam that are not preceded by an Initial Application Package with a feasibility study will be returned. Feasibility and siting studies conducted as part of an environmental assessment, environmental impact statement, or other document under the National Environmental Policy Act (NEPA) process or other formal process are acceptable as long as the above guidelines are followed. Siting Study A siting study is required for Class 1 and II dams to justify that the proposed location of the dam is the best location for the type and configuration of the dam to be constructed. Siting studies should include the following considerations: Type of dam Geology and hydrogeology of bedrock and overburden Construction material borrow sources Local and regional hydrology Local and regional seismic setting and faulting Opportunities for mitigation of dam break flood waves Units of Measurement Units of measurement in all submittals should be in conventional, English format, except for permeability or hydraulic conductivity, which m ay be reported in centimeters per second. Metric standards m ay be included in brackets at the applicant's convenience. Otherwise, unit systems should not be mixed. Suitability for construction A siting study may be included with the feasibility study if the appropriate siting criteria are considered. Dam owners are encouraged to conduct a siting study for Class III darns, but submittal of that study to Dam Safety is not specifically required by the regulations. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 5-5 Tier 10 Revision 1 June 30, 2005 Attachment F Page 53 of 230 ED 002061 00172725-00053 Go to Table of Contents C hapter 5. C onstruction A pplication D etails 5.1.7 Design Scope Proposal The purpose of the design scope proposal is to define important design standards and the scope of work proposed to determine certain parameters used in the detailed design. The proposed scope of work and related design criteria should be defined in advance for the following subject areas at a minimum: Hydrology and hydraulics Methods for determining inflow design flood (IDF) and spillway capacity (See Section 6.1.) Stability Evaluation method with proposed safety factors for static and pseudo-static stability analysis, deformation analysis, or finite element analysis, as appropriate (See Section 6.2.) Seismicity Level of sophistication and approach to studies necessary to define seismic parameters for location of the dam, including maximum credible earthquake (MCE), maximum design earthquake (MDE), operating basis earthquake (QBE), and potential ground motions (See Section 6.3.) Seepage Planning the Design Planning the design is one of the most important first steps in the regulatory life of a dam. Early agreement on the scope of the design will maximize the efficiency of the permitting process. The design scope proposal is not intended to define the parameters used in the design, hut to define the proposed level of work, methodologies, levels of analysis, and approaches to determine and evaluate those parameters that are required for the safe design and construction of the dam. Methods to determine foundation and dam permeability, seepage analysis, and gradient control (See Section 6.4.) Additional details about these important aspects are included in Chapter 6. The design scope proposal should also specify the level of design quality assurance (DQA) and design quality control (DQC) to be conducted during the design. For example, for new Class I dams, a design review board may need to be established. A detailed discussion of DQA/DQC is beyond the scope of these guidelines, but additional information may be found in Q uality M an ag em en t by the USACE (1993). 5.2 Preliminary Design Package Detailed guidance on the development of the information required for the Preliminary Design Package is provided in the following subsections. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 5-6 Tier 10 Revision 1 June 3 0 ,2 0 0 5 Attachment F Page 54 of 230 ED 002061 00172725-00054 Go to Table of Contents C hapter 5, C onstruction A pplication D etails 5.2.1 Water and Land Use Rights The following information must be submitted with the Preliminary Design Package. Proof of a water use permit or other water right, as required by AS 46.15. For construction of new dams or modifications that increase the reservoir size or raise the hazard potential classification, proof of land ownership or other documented legal permission to construct the dam, appurtenant works, and reservoir. The applicant must provide copies of the respective permits or a letter describing the status of the permitting process to the ADNR. 5.2.2 Proposed Financial Demonstration Constructing and operating a dam is an expensive and long-term commitment. A dam owner must demonstrate to the ADNR the financial ability to responsibly manage the facility during the life of the project. A demonstration of financial ability is required for construction of new dams or for modifications that increase the size of the reservoir or raise the hazard potential classification. If financial ability cannot be demonstrated, a Certificate of Approval to Construct a Dam will not be issued. In tire Preliminary Design Package, the dam owner must propose the methods for which the financial ability will be demonstrated for The Public versus Private Dam Paradox certain costs, depending on whether the For demonstrating financial ability, the applicant is a government agency or not. The assum ption is that a government agency proposed methods for demonstrating financial will only operate a dam that provides ability must be approved by the ADNR, as some public benefit over an indefinite indicated in 11 AAC 93.171(d). period of time, and routine operation and The following language is included in the regulations under 11 AAC 93.171(f)(2)(C): (i) For a government agency, financial ability may be demonstrated through taxing authority or other revenue generating ability, and by the pertinent bond, ordinance, resolution, or law as maintenance costs must be budgeted and funded. In contrast, a privately owned dam is for the primary benefit of the dam owner at his own expense. However, if that entity goes bankrupt, funds for the cost of mitigating the risk of the dam must be available. may be required to provide sufficient money to pay the costs of operating and maintaining the dam in a safe condition and complying with the requirements of 11 AAC 93.151 -11 AAC 93.201; (ii) For an applicant other than a government agency, the owner must provide a performance bond or other financial assurance adequate to provide sufficient money to pay for the costs of safely breaching the dam at the end of the dam's service life and restoring the stream channel and reservoir land to natural conditions, or for the costs of performing reclamation and post-closure monitoring and maintenance, as required under 11 AAC 93.172. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 5-7 Tier 10 Revision 1 June 3 0,2005 Attachment F Page 55 of 230 ED 002061 00172725-00055 Ci to Table of Contents C hapter 5, C onstruction A pplication D etails For dam owners that are not government agencies and for which a performance bond or other form of financial assurance is required to demonstrate financial ability, the agreement and instrument should be prepared and executed to account for all design and construction costs for the following: Dewatering the reservoir Safely breaching the darn to a point at which there is no longer any impoundment under any flood conditions Restoring the stream channel and reservoir land to natural conditions Reclamation and post-closure monitoring and maintenance, if appropriate For certain facilities where the dam is not breached or removed, such as a mine tailings dam, the financial assurance required is specified in 11 AAC '172(a)(6)(c) as a "performance bond or other financial assurance adequate to provide sufficient money to pay for the costs of post closure monitoring, operation, maintenance, and inspection." See Section 13.2.2 for more information, 5.2.3 Topographic Map of Dam Site A topographic map of the dam location should be included in the Preliminary Design Package and should incorporate the following presentation and content details: Legible engineering scale Legible contour interval Reservoir area at normal and maximum water storage levels Survey datum Coordinate system Property lines and other boundaries Locations of spillways, outlet works, borings, test pits, and material sites Guidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 5-8 Tier 10 Revisio n ! June 30, 2005 Attachment F Page 56 of 230 ED 002061 00172725-00056 Go to Table of Contents C hapter 5. C onstruction A pplication D etails 5.2.4 Preliminary Drawings A preliminary drawing package should be submitted with the Preliminary Design Package. These drawings may be in a draft form, sometimes referred to as 35% complete. The following drawings should be included at a minimum: Profile view' of dam along dam axis, showing elevation of the crest of the dam, locations and elevations of spillways and outlet works, and geological investigation information Cross section view's of the dam at the maximum height, spillways, and outlet works, including elevation and width of crest, slopes of upstream and downstream faces, thickness of erosion control structures and zoned fills, and locations of underdrains, cutoff walls, and bonding trenches Suggested Drawing Conventions Left and right abutments looking downstream Water flows from /eft to right in cross sections North arrow toward the top of page on plan views Use of engineering scale Inclusion of a bar scale on ail drawings Submittal Standards Two copies of the preliminary drawing package should be submitted. Drawings that are 11 inches by 17 inches are acceptable if they are legible and to scale (no offscale reductions). Larger drawings should be submitted if necessary for clarity. The survey datum coordinate system and contour intervals should be clearly identified. 5.2.5 Engineering Science Reports The following engineering science reports and tire details indicated should be submitted as part of the Preliminary Design Package: Geological and geotechnical investigation report for the dam site, reservoir area, spillways, outlet works, appurtenant works, and material si tes Location and geological maps Locations and logs of borings and test pits Geological cross sections along dam centerline and perpendicular to centerline Material analyses and laboratory test results Recommend ations for foundation treatment, stability analyses, and seepage control Other relevant information Seismic report See Section 6.3 for detailed information abou t the seismic report. Guidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 5-9 Tier 10 Revision June 30, 2005 Attachment F Page 57 of 230 ED 002061 00172725-00057 Go to Table of Contents C hapter 5. C onstruction A pplication D etails Hydrology design re p o rt Methods and references used to determine the IDF Drainage basin characteristics Streamflow and precipitation data Reservoir inflow and outflow hydrographs Estimate of flood event impacts on areas downstream, including an incremental damage assessment, if conducted Other relevant information Submittal Standards Engineering science reports may be combined into one binder. Two copies should be submitted. The reports should be sealed by the engineer of record. Electronic Submittals Dam Safety encourages electronic submittals to help expedite distribution and review of important documents. Unlocked Adobe Acrobat files are most convenient for viewing, commenting, and transmitting both text and drawings through computer mediums. MSW ord and Excel files are acceptable. Dam Safety does not support AutoCAD or other drawing file formats, in any event, paper copies, as described in the text of these guidelines, are required. 5.2.6 Revised Proposed Schedule The proposed schedule submitted with the Initial Application Package should be updated and resubmitted with the Preliminary Design Package. The revised proposed schedule should give approximate dates for the following: Detailed Design Package submittal (See Section 5.3.) Final Construction Package submittal (See Section 5.4.) Beginning of construction The revised proposed schedule should allow for the Dam Safety target review times indicated in Figure 4.1. Dam Safety will cooperate as much as possible to accommodate the revised proposed schedule. 5.3 Detailed Design Package The Detailed Design Package should contain the majority of the information needed for Dam Safety to make a determination of the safety of the dam and appurtenant works. It is not necessary to resubmit information contained in the Initial Application Package and Preliminary Design Package, although revised documents or supplements may be included or previous submittals can be rolled into the Engineering Design Report, as convenient to address review comments from Dam Safety. References to previous submittals should be specified as appropriate. Supplemental information or addenda may be requested by Dam Safety based on a technical review of the final submittals. Additional details about the submittals in the Detailed Design Package follow. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 5-1 0 Tier 10 Revision 1 June 3 0 ,2005 Attachment F Page 58 of 230 ED 002061 00172725-00058 Go to Table of Contents C hapter 5. C onstruction A pplication D etails 5.3.1 Engineering Design Report The engineering design report should contain all information necessary to support the design that has not been addressed in the previous submittals. This report typically includes the following items: A description of all methodologies, references, formulas, and assumptions used in developing the design criteria and engineering evaluations An evaluation of the structural stability of the darn, foundation, and appurtenant features An evalua tion of the performance of the dam, founda tion, and appurtenant features during a seismic event Descriptions, physical analyses, and permeability analyses, as appropriate, of the materials used in the construction of the dam A seepage analysis for the dam and foundation, including filter criteria to prevent piping of fine-grained materials Design criteria, calculations, and rating curves for the spillways and outlet works, including freeboard and other hydraulic evaluations such as energy dissipators A storage-versus-depth curve and a storage-versus-area curve for the reservoir Recommendations for diverting water during construction, as appropriate Recommendations for special construction considerations, first filling of reservoir, operations, maintenance, instrumentation, and monitoring Design evaluations and recommendations for other features of the dam and appurtenant works Submittal Standards Two copies of the engineering design report should be submitted. The report should he sealed by the engineer of record. For Class I and II dams, the report should contain backup data such as calculation sheets and input and output data for final computer runs. 5.3.2 Design Drawings Design drawings may be submitted in a draft format, often referred to as 95% complete. The design drawings should include the drawings submitted in the Preliminary Design Package, plus the additional drawings necessary to completely describe the project, including the following: Additional cross sections of the dam Spillway plan views and cross sections G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 5-1 i Tier 10 Revision 1 June 3 0 ,2005 Attachment F Page 59 of 230 ED 002061 00172725-00059 Go to Table of Contents C hapter 5. C onstruction A pplication D etails Detail drawings as needed Design drawings for appurtenant structures Construction sequence drawings, if required Other drawings as necessary Submittal Standards Two copies of the design drawing package should be submitted. Drawings that are 11 inches by 17 inches are acceptable if they are legible and to scale (no offscale reductions). Larger drawings should be submitted if necessary for clarity. Drawings should include the following: Cover sheet that identifies the project, dam owner or operator, engineer, and location Index of drawings, legends, drafting standards, conventions, abbreviations, codes, or other information necessary to inter pret the drawings, including specific datum and coordinate references Title block with unique drawing numbers, initials for designers and engineering review, revision numbers, and dates Stamp or mark on all drawings stating "issued for Agency Review" or similar language 5.3.3 Draft Construction Specifications Construction specifications also may be submitted in draft form, but should at least indicate all sections necessary for bidding and construction. Submittal Standards The specifications should include a cover sheet with the project name and date. The format of the Construction Specifications Institute (CSI) is recommended. The specifications must include a table of contents. 5.3.4 Construction Quality Assurance/Quality Control Plan A plan to control the quality of the construction work and assure its compliance with the drawings and specifications is required. The scope of the plan depends on the complexity and hazard potential classification of the dam. The development of a CQA/QC plan is discussed in Section 7.2. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 5-12 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 60 of 230 ED 002061 00172725-00060 Ci to Table of Contents C hapter 5, C onstruction A pplication D etails 5.3.5 Revised Proposed Schedule The revised proposed schedule submitted with the Preliminary Design Package should he updated again and resubmitted with the Detailed Design Package. The revised proposed schedule should give approximate dates for the following: Final Construction Package submittal (See Section 5.4.) Requested date for Certificate o f Approval to Construct a Dam Bid deadline and notice of award Beginning and end of construction - estimated period of construction The revised proposed sched ule should allow for the Darn Safety target review times indicated in Figure 4.1. Darn Safety will cooperate as much as possible to accommodate the revised proposed schedule. 5.4 Final Construction Package A Final Construction Package that includes the information described in the following subsections should be submitted to Dam Safety. After this information is received and approved, Dam Safety will issue the Certificate of Approval to Construct, Modify, or Repair a Dam. 5.4.1 Final Construction Drawings The final construction drawings should include the final versions of the drawings submitted in the Detailed Design Package completed to the detail necessary to construct the dam in accordance with the intent of the design and the hazard potential classification of the dam. Submittal Standards One copy of final construction drawing package should be submitted. Drawings that are 11 inches by 17 inches are acceptable for submittal if they are legible and to scale (no off-scale reductions). Larger drawings should be submitted if necessary for clarity and should be provided to the contractor for construction. Each drawings should include the following: Seal and signature of the engineer of record Stamp or mark stating "Issued for Construction" or similar language Current revision number and date G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 5-13 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 61 of 230 ED 002061 00172725-00061 Go to Table of Contents C hapter 5. C onstruction A pplication D etails 5.4.2 Final Construction Specifications The final version of construction specifications must be submitted with the Final Construction Package and include all sections necessary for construction. S ubm ittal Standards The specifications should include a cover sheet with the project name, revision number, date, and the seal and signature of the engineer of record. 5.4.3 Construction Schedule A schedule for dam construction that includes the following specific information should be provided with the Final Construction Package: Key elements of construction Milestones, including beginning of construction and the estimated date for substantial completion Mandatory inspection points (See Subsection 7.2.3.) If the construction is not accomplished according to schedule, the construction schedule must be revised and resubmitted at the request of Dam Safety. This schedule may or may not be the contractor's construction schedule, at the discretion of the applicant. However, Dam Safety may require the contractor's construction schedule as a condition to the Certificate o f Approval to Construct a Dam, especially for a large or complex project. A contractor's construction schedule should also include the key elements of construction, milestones, and mandatory inspection points. 5.4.4 Certified Cost Estimate The certified final cost estimate shou ld be submitted with the Final Construction Package. This estimate should be based on the following information: Actual accrued engineering costs, including design, site investigation, laboratory testing, and surveying Estimated cost of additional engineering and surveying, construction supervision, CQA/QC, and other direct costs associated with design and construction Either the estimated cost of construction based on the contractor bid or a cost estimate prepared by a professional construction cost estimator, the engineer, or the chief financial officer of the dam owner or operator | Certifying the Cost Estimate | The requirement for a certified j cost estimate for calculating the | application fee is intended to \ provide equity among applicants | while assuring the A DN R that the | fee is appropriately calculated. j The certification should be | provided by a professional | construction cost estimator, the engineer, or the chief financial ||I officer of the dam owner or |I operator. | I Guidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 5-14 Tier 10 Revision 1 June 30, 2005 Attachment F Page 62 of 230 ED 002061 00172725-00062 Ci to Table of Contents C hapter 5, C onstruction A pplication D etails 5.4.5 Application Fee Supplement A non-refundable supplement for the application fee should be included with the Final Construction Package if the certified cost estimate exceeds the estimated cost used for the application fee deposit described in Subsection 5.1.3. See Section 3.4 for information about the fee calculation. 5.4.6 Demonstration of Financial Ability The Final Construction Package should include the demonstration of financial ability approved by the ADNR, as discussed in Subsection 5.2.2. A Certificate of Approval to Construct a Dam will not be issued if financial ability cannot be demonstrated to the satisfaction of the ADNR. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 5-15 Tier 10 Revision 1 June 30, 2005 Attachment F Page 63 of 230 ED 002061 00172725-00063 Go to Table of Contents j C hapter 5, C onstruction A pplication D etails G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 5-16 Tier 10 Re v is io n ! June 3 0,2005 Attachment F Page 64 of 230 ED 002061 00172725-00064 Go to Table of Contents Guidelines for Cooperation with the Alaska Dam Safety Program Chapter 6 DESIGNING A DAM IN ALASKA 6.1 Hydrology and Hydraulics ............ 6-2 6.1.1 Inflow Design Flood....................................................................................................6-2 6.1.2 Precipitation and Snow pack......................................................................................6-4 6.1.3 Hydraulics..................................................................................................................... 6-4 6.2 Stability........ ............ 6-4 6.3 Seismicity.................................................................................................................................6-5 6.3.1 Minimum Scope............................................................................................................ 6-6 6.3.2 Design Earthquake Levels........................................................................................... 6-6 6.3.3 Seismic Study Phases................................................................................................... 6-7 6.4 Seepage.............. .....................................................................................................................6-8 6.5 Cold Regions........................................................................................................................ 6-10 6.5.1 Siting................ 6-10 6.5.2 Materials of Construction and Construction Process............................................ 6-10 6.5.3 Operation............. ............ 6-11 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 65 of 230 ED 002061 00172725-00065 Go to Table of Contents Chapter 6 DESIGNING A DAM IN ALASKA In this chapter: > A b rie f review o f design issues im p o rta nt to the ADSP > Limited design guidance for important performance parameters > References to other detailed design guidance resources The mission of the ADSP is to protect life and property, as stated in Chapter 1. The mission does not include dictating how a facility is designed and constructed, except to the extent necessary to ensure that the darn is safe. For this purpose, Dam Safety desires to establish a reasonable standard of care and performance in order to administer the program in a technically sound and equitable manner that leads to the success of the mission. Review and approval of designs submitted for the purpose of receiving a certificate of approval are completed on an individual basis and approved or disapproved based on the merits of the particular project and the submitted information. Designs that follow accepted industry standards and procedures are desirable. Acceptable design standards are provided by the following: U.S. Army Corps of Engineers (USAGE) U.S. Bureau of Reclamation (USER) U.S. Department of Agriculture (USDA), Natural Resources Conservation Service (formerly the Soil Conservation Service) Federal Emergency Management Administration (FEMA) Federal Energy Regulatory Commission (FERC) U.S. Society on Dams (USSD) (formerly U.S. Committee on Large Dams [USCOLD]) American Society of Civil Engineers (ASCE) Many acceptable design guidance documents exist. Dam Safety does not wish to discourage new or innovative design approaches that may be technically sound. Nevertheless, all designs, especially those that do not follow accepted industry standards, must be accompanied by references, analyses, and technical justification sufficient to show that the design approach is sound and will meet the intent of the dam safety regulations. The following sections present limited information about selected design issues that are important to the ADSP and in some cases unique to Alaska. Guidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 6-1 Tier 10 Revision 1 June 30, 2005 Attachment F Page 66 of 230 ED 002061 00172725-00066 Go to Table of Contents C hapter 6, D esigning a Da m in A laska 6.1 Hydrology and Hydraulics Data compiled by the National Performance of Dams Program (NPDP) at Stanford University indicate that flooding is the leading cause of darn failures in the nation (NPDP, 2000). Dam failure data compiled by Dam Safety indicate that Alaska is not an exception. Figure 6-1 shows Alaska data compared to national statistics. Failures caused by flooding can generally he attributed to an inadequate understanding of the hydrology and an insufficient hydraulic capacity of the spillway system on the dam. The hydrological and hydraulic designs are two of the most important aspects of a dam. Suspected Cause Figure 6-1. Comparison of Dam Failures in the United States and Alaska Note: National data reflect 2,127 incidents reported between 1989 and 1998 (NDPD, 2000). Alaska data are based on documented failures since 1964. 6.1.1 Inflow Design Flood The IDF is the primary objective of the hydrological portion of the design. It is defined in 11 AAC 93.195(c) as "the flood flow above which the incremental increase in the downstream flood caused by a failure of the dam does not result in any additional danger downstream." As indicated in 11 AAC 195(b)(l and 2), information for determining the IDF should he developed in substantial accordance with either of the following: Federal Guidelines for Dam Safety: Selecting and Accommodating Inflow Design Floods for Dams, published by the FEMA (1998d) Methods approved by Dam Safety that adequately assess and characterize the design hydrology and are based on the hazard potential classification of the dam G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 6-2 Tier 10 Revision 1 June 3 0,2005 Attachment F Page 67 of 230 ED 002061 00172725-00067 Go to Table of Contents C hapter 6. D esigning a Da m in A laska In summary, the FEMA report recommends the following standards for the IDF: Minimum standard for Class III (low) hazard potential dam. - IDF based on a storm event with a return frequency selected to "protect against loss of benefits during the life of the project and to keep O&M costs to a minimum,. in general, the IDF with "an average return frequency of less than once in 100 years," also known as the 100-year flood, or a flood with a probability of occurrence of 0.01 (1%) in any given year, is adequate for Class III dams. Maximum standard for all hazard potential class dams - IDF based on probable maximum flood (PMF) based on probable maximum precipitation (PMP). Calculated standard for all hazard potential class dams - IDF based on "incremental hazard evaluation," sometimes referred to as an incremental damage assessment. In other words, the IDF is the flood with a magnitude at which the failure of the dam simultaneously with the peak of the IDF hydrograph does not contribute to any additional flood damage downstream. For purposes of these guidelines, this definition of the IDF is considered the same as the definition given in 11 AAC 93.195(c). Acceptable methods for determining the IDF hydrograph include the following: Hydrologic modeling programs, such as HEC-HMS (preferred) or HEC-1 published by the Hydrologic Engineering Center of the USAGE Urban Hydrologyfor Small Watersheds, Technical Release 55 (TR-55), published by the USDA Soil Conservation Service (1986) For Class III (low) hazard potential dams located in any area of Alaska, the IDF may be calculated by using the regression equations in the following usefu l reference: Magnitude and Frequency of Floods in Alaska and Conterminous Basins of Canada (Jones and Fahl, 1994), published by the U.S. Geological Survey (USGS) Correction factors for standard errors should be considered. In any case, the accuracy of the calculated values and the suitability to the proposed project must be verified. The IDF may be determined by using other methods proposed by the designer in the design scope proposal and approved by Dam Safety. (See Section 5.1.7.) Water Management at Tailings Dam s Managing water at tailings dams represents a unique chaiienge for designers and operators. D uring the operating phase, an emergency spillway might not exist and the reservoir must then retain the full volume of the IDF. in this case, a detailed water balance methodology m ust be developed to carefully monitor and maintain a reserve storage capacity. For closure, the facility must be modified to safely handle an IDF, typically the PMF or some other extreme event. See Subsection 13.2.2 for other important closure details that should be considered in the initial design of a tailings dam. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 6-3 Tier 10 Revision 1 June 3 0,2005 Attachment F Page 68 of 230 ED 002061 00172725-00068 Go to Table of Contents C hapter 6. D e s i g n i n g a Da m in A laska 6.1.2 Precipitation and Snowpack Unfortunately, current and reliable hydrological information in Alaska is limited. Records are available for select locations such as urban areas or major streams, and some projects are required to collect data for other purposes. Preferably, site-specific rainfall data or stream flow records such as those available from the USGS should be used in a hydro-meteorological analysis to develop the design storm. If sufficient data are available, this approach must be used for Class I and II darns. References must be cited for data and evaluation methodologies, and raw data must be presented in the hydrology report. In the absence of sufficient data, or for comparison to calculated values, the following documents are available for determining frequency-based precipitation and PMP events: Probable Maximum Precipitation and Rainfall Frequency Data for Alaska for Areas to 400 Square Miles, Durations to 24 Hours, and Return Periods from 1-100 Years, Technical Paper 47 (TP-47) (Miller, 1963) Probable Maximum Precipitation and Snowmelt Criteria for Southeast Alaska, Hydrometeorological Report 54 (HMR-54) (Schwartz and Miller, 1983) For Class 1 dams in Southeast Alaska, snowpack should be considered in accordance with HMR-54. For Class I dams in the remainder of Alaska, the effects of snowpack should be considered in accordance with the following: Chapter 10 of Engineering and Design - Runofffrom Snowmelt, published by the USAGE (1998) 6.1.3 Hydraulics Limited guidance on hydraulics is also given in the FEMA guidelines (1998d), including recommendations for the following: IDF reservoir rou ting Spillway and outlet works Freeboard Additional references may be required for the detailed design and evaluation. Details of hydraulic calculations and references should be included in the engineering design report for all hazard potential classification dams. 6.2 Stability Stability must be demonstrated for all types and hazard potential classification dams under a variety of loading conditions. Many acceptable empirical and numerical methods are available for evaluation of the stability of dams. The scope of the stability analysis should be defined in the design scope memorandum, including methods of analysis and verification and references for proposed safety factors, or objectives of deformation analyses or finite element analyses. Guidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 6-4 Tier 10 Revision 1 June 30, 2005 Attachment F Page 69 of 230 ED 002061 00172725-00069 Go to Table of Contents C hapter 6. D esigning a Da m in A laska The general guidance shown in Table 6-1 should be considered when defining the scope of the stability analysis in the design scope proposal. (See Section 5.1.7.) The stability analysis requirements for hazard potential classification dams are summarized below. Class I (high) hazard potential dams - Detailed stability analysis is required. All computer stability analyses must be verified with manual calculations or other approved methods. Class II (significant) hazard potential dams - Detailed stability analysis is required. Graphical or empirical evaluations may be used to verify computer results. Class III (low) hazard potential dams - Published empirical or graphical methods may be adequate for small embankment dams less than 25 feet in height. Embankment dams greater than 25 feet in height should he evaluated in the same manner as Class II dams. Other types of dams, such as concrete, steel, or timber frame dams, may require a combination of methods. For any given analysis, all input data and results must be clearly documented, including assumptions, sources of information, references, and computer outputs. Table 6-1. General Guidance for a Stability Analysis Hazard P o te n tia l Dam Type Com puter A nalysis Class I Ail P Class i! Ai! P Class III Earth and rock fill, <25 feet tal! O, S Class ill Earth and rock fill, 25 feet or P taller Class ill All others s P = Primary method of analysis S = May be required under special circumstances V = Verification of primary method O = Optional method of anaiysis G raphical or E m pirical A nalysis V P V 0 Manual A nalysis V O 0 F in ite E lem ent A nalysis S S s 6.3 Seismicity Evaluation and design of all new dams, or major modifications of existing dams should consider the effects of seismicity on the stability and performance of the facility, including appurtenant structures, reservoir, and associated equipment. A study to assess the seismicity is required for all dams. Depending on the complexity of the project, this study may require an interdisciplinary team that includes seismic, geologic, geotechnical, and structural engineering specialists. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 6-5 Tier 10 Revision 1 June 30, 2005 Attachment F Page 70 of 230 ED 002061 00172725-00070 Go to Table of Contents C hapter 6, D esigning a Da m in A laska 6.3.1 Minimum Scope The scope and detail of each seismic study will depend on the dam hazard potential classification and location, the regional seismic environment, and the site-specific geologic and topographic conditions. However, each study should address the following four key elements: Define the seismic environment such as regional earthquake sources, historical activity, and recurrence rates, and characterize the levels of potential ground motions such as duration, frequency, amplitude and predominant period of ground vibrations, and peak ground accelerations, as needed for design and monitoring during operation Evaluate the potential for fault movements rupturing the surface at or near the dam, liquefaction, lateral ground spreading and cracking, and overtopping caused by seiches or waves induced by slope failures around the reservoir Analyze the dynamic response of the dam to inertial forces and potential reductions or loss of strength and stiffness in the foundation and dam materials as a function of the design ground motions Analyze the facility to verify that each element, including embankments, foundations, appurtenances, and reservoir, will adequately resist translational (sliding wedge or block), rotational or flow-type slides, or excessive settlements and deformations during the design earthquakes 6.3.2 Design Earthquake Levels Two levels of design earthquake must be established: Operating basis earthquake (OBE) represents the ground motions or fault movements from an earthquake considered to have a reasonable probability of occurring during the functional life-time of the project. All critical elements of the project (such as darn, appurtenant structures, reservoir rim, and equipment) should be designed to remain functional during the OBE, and any resulting damage should be easily repairable in a limited time. The OBE can be defined based on probabilistic evaluations, with the level of risk (probability that the magni tude of ground motion will be exceeded during a particular length of time) being determined relative to the hazard potential classification and location of the dam. Maximum design earthquake (MDE) represents the ground motions or fault movements from the most severe earthquake considered at the site, relative to the acceptable Maximum Credible Earthquake The terminology used for describing various design earthquakes and seismic hazards is inconsistent in the various references. The maximum credible earthquake (MCE) is defined herein as the greatest earthquake that reasonably could be generated by a specific seismic source, based on seismoiogical and geologic evidence and interpretations. The M D E and OBE are defined in the text. Other terminology m ay be acceptable, but specific references and definitions must be included. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 6-6 Tier 10 Revisio n ! June 30, 2005 Attachment F Page 71 of 230 ED 002061 00172725-00071 Go to Table of Contents C hapter 6, D esigning a Da m in A laska consequences of damage in terms of life and property. All critical elements of the dam and appurtenant structures for which the collapse or failure could result or precipitate an uncontrolled release of the reservoir must be designed to resist the MDE. In addition, the dam and appurtenances must be designed to resist the effects of the MDE on the reservoir and reservoir rim. The MDE may be defined based on either deterministic or probabilistic evaluations, or both. Table 6-2 provides a range of probabilistic return periods (risk) considered appropriate for defining the OBE and MDE, as a function of the hazard potential classification of the dam. Within the context of these ranges, the OBE return period for a given project should be selected in direct correlation with the frequency of regional earthquakes, the useful life span of the facility, and the difficultly of quickly accessing the site for repairs. The return period selected for the MDE should be selected in direct correlation with the magnitude of the maximum credible earthquake (MCE) for the known or suspected regional sources; the dam type, size, and geometry; and the reservoir capacity. Further guidelines for selecting the ground motions associated with these two levels of seismic hazard are provided in Dobry et al. (1999) and USCOLD (1999). Table 6-2. Operating- and Safety-Level Seismic Hazard Risk Dam Hazard C lassification j II il! R eturn Period, Years O perating B asis E arthquake M axim um Design E arthquake 150 to >250 70 to 200 50 to 150 2,500 to MCE 1,000 to 2,500 500 to 1,000 6.3.3 Seismic Study Phases Seismic studies for new dam design should be conducted in two phases, which are described belowc Seismic report phase - This phase should occur early in the planning of the project and be included with the Preliminary Design Package submittals described in Subsection 5.2.5. The seismic report will include preliminary evaluations as needed to establish an understanding of the potential influence of the OBE and MDE on the type, geometry, and size of the dam and reservoir. Given the preliminary nature of this phase, evaluations can generally be based on published information and simplified methods. After the risks have been established, preliminary values for the OBE and MDE parameters can be estimated based on regional geologic mapping (for example, USGS publications and Plafker and Berg, 1994) and seismological studies (for example, Wesson et al., 1999; and USGS National Seismic Hazard Mapping Project - Interactive Deaggregation, 2003). Evaluations of the potential for liquefaction should be presented based on the local geology, historical record, and simplified methods with the use of standard penetration test values from the geotechnical evaluation (for example, Seed et al., 2001; and Youd and Idriss, 1997). Evaluations of the response and stability of the G uidelines for C ooperation w i t h the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 6-7 Tier 10 Revision 1 June 3 0 ,2 0 0 5 Attachment F Page 72 of 230 ED 002061 00172725-00072 Go to Table of Contents C hapter 6. D e s i g n i n g a Da m in A laska dam should be presented by using limit-equilibrium or linear-elastic analysis and generic response spectra found in applicable design codes or standards (see methods in Kramer, 1996). The seismic report phase should also refine the scope and detail of the evaluations to be performed during the subsequent design evaluations of the facility conducted in the second phase of the seismic evaluation of tire dam. If the associated risks are high because of the location of the darn and its hazard potential classification, more sophistica ted analyses may be required (USCOLD, 1999); for example, with deterministic and probabilistic evaluations or acceleration time histories. Seismic design phase - This phase should occur during the detailed design of the project and be included in the engineering design report submitted as part of the Detailed Design Package and described in Subsection 5.3.1. The seismic design phase of the seismic study will include formal evaluations of each critical element of the dam as needed to assure that the facility meets the performance requirements under the OBE and MDE. The effort and sophistication of the work conducted during this phase of the seismic study will depend on the hazard potential classification of the dam, and the magnitude of the OBE and MDE. For example, the dynamic and stability evaluations for all Class I and II dams located in a highly seismic region (with peak ground accelerations greater than about 30% to 40% of gravity or peak shear strains greater than about 12%) should utilize advanced one- and two-dimensional site response analysis techniques (for example, Lee & Finn, 1978; and ldriss et al, 1973) to more accurately model the nonlinear behavior of soil subject to earthquake loading. On the other hand, the dynamic stability evaluations for Class III dams or Class II dams located in regions with low seismicity (with peak ground accelerations less than about 5% to 10% of gravity) can utilize the same simplified methods followed in the seismic report phase, and no additional detailed evaluation may be required. However, the simplified methods presented in the seismic report should be reviewed with respect to the final design of the dam, and should be revised if necessary. Evaluations of Class I and II dams located in regions of moderate seismicity can utilize techniques between these ranges, such as equivalent-linear, one-dimensional, site response analysis (for example, ldriss and Sun, 1992). 6.4 Seepage Seepage must be considered for all hazard potential classification dams; however, the scope of the analysis depends on a number of factors, including the size and type of dam and the foundation and construction materials. The following are conditions and suggested levels of evaluation based on the hazard potential classification of the dam. All hazard potential class dams The material properties, including permeability, must be estimated for both the foundation and construction materials. G u id elin es fo r C o o p e r a t io n w ith the A laska D a m Safety Program Sierra Club v. EPA 18cv3472 NDCA 6-8 Tier 10 R evisio n 1 June 3 0 ,2 0 0 5 Attachment F Page 73 of 230 ED 002061 00172725-00073 Go to Table of Contents C hapter 6. D esigning a Da m in A laska Filters must be included in all embankment dams between core materials and drains. Soil filter criteria must be demonstrated based on actual gradation tests. References to filter criteria standards must be included. Appropriate seepage cutoff or reduction measures must be included to limit gradients and prevent piping and erosion. All dams must include the appropriate drainage features to control seepage pressures and gradients, including uplift. Phreatic surfaces must not daylight on the downstream face of embankment dams. Appropriate measures to control seepage along penetrations through the dam or at contact planes between different materials, such as the interface between concrete and soil fill, must be included. Class III (low) hazard potential dams Empirical evaluations combined wi th engineering controls may be used to address seepage. Published values for material properties may be used in lieu of laboratory testing to a limited extent; however, sufficient index testing must be completed to accurately classify all materials to be used in construction. Class II (significant) hazard potential dams Foundation conditions must be thoroughly evaluated in the geotechnical program, including rock coring and packer testing, as appropria te. Laboratory testing must be used to determine permeability and index properties of the core, filter, and drainage materials. Published permeability values may be used for coarsegrained drainage ma teria Is. In situ soil and rock, excavated material to be reused, and borrow sources must be tested. Appropriate foundation preparations, such as cleaning, slush grouting, pressure grouting, and dental concrete, must be included in the construction specifications. A numerical analysis may be required for certain Class II darns for which seepage control is a primary performance parameter. Class I (high) hazard potential dams All Class II conditions apply. Seepage Monitoring All dams should he monitored for seepage. Increases in seepage rates or turbidity can be key indicators of a developing failure situation. Seepage monitoring requirements should be specified by the engineer and included in the operations and maintenance manual discussed in Chapter 8. Seepage monitoring software is available from the Federal Emergency Management Agency's National Safety Program. Contact Gene Ziezel at (202) 646-2802 for more information. G u id e lin e s f o r C o o p e r a t io n w ith the A laska D a m Safety Pro g ra m Sierra Club v. EPA 18cv3472 NDCA 6-9 Tier 10 R evisio n June 3 0 ,2 0 0 5 Attachment F Page 74 of 230 ED 002061 00172725-00074 Go to Table of Contents C hapter 6. D esigning a Da m in A laska Geotextile filters may not be used as primary filters in critical components of Class 1 dams. A numerica l ana lysis must be completed. 6.5 Cold Regions When designing a dam in Alaska, the effects of extreme cold must be considered in siting, construction, and operation. These issues must be addressed during the planning stages. Additional information is provided in the following subsections. 6.5.1 Siting Large areas of the state have permafrost that ranges from discontinuous areas to continuous zones that are hundreds of feet thick. The presence of permafrost at a proposed project area constitutes a key design element and performance parameter. Disturbance of the ground surface above permafrost alters the thermal regime of the area, resulting in changes to the permafrost. Clearing vegetation, excavation, construction, or the impoundment of water or tailings can affect permafrost. Thawing of permafrost soils can result in loss of hearing capacity, excessive settlement, or increased seepage, which can lead to the failure of the dam. Consequently, the potential for permafrost must be considered when siting a dam. If permafrost is present at the preferred location of the dam, the geotechnical and geological investiga tion must thoroughly classify the extent and nature of the permafrost and include recommendations for the design. The design report must evaluate the effects on permafrost caused by of the construction and operation of the dam and reservoir, and must include a thermal evaluation that uses approved methodologies. 6.5.2 Materials of Construction and Construction Process Cold tempera tures can also influence the selection of construction materials and the quality of work that occurs during construction. Design details and construction specifications must address the affects of freezing temperatures on the following items, at a minimum: Specifying and installing geomembranes, plastic pipes, or other materials that may be sensitive to cold Placing and compacting fill Pouring and curing concrete Welding steel or geomembrane Ice Load Design CEA Technologies Inc., sponsored b y the Canadian Electric Association, recently published Static Ice Loads on Hydroelectric Structures: Ice Load Design Guide. The following sections of the report m ay prove useful for designing d am s in Alaska: Sum m ary Report Ice Load Design Guide Ice Load Prediction Computer Program For more information, visit the company Web site at www.ceatech.ca. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 6-10 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 75 of 230 ED 002061 00172725-00075 Go to Table of Contents C hapter 6. D esigning a Da m in A laska 6.5.3 Operation The design of a dam must consider and address the following issues that can affect dams during routine operations: Runoff from snowmelt Ice loading on dam and appurtenances Freeze/thaw effects on concrete dams and appurtenances Cold-temperature effects on exposed plastic pipes or geomembranes ice lens formation in fine-grained soils Frost jacking of buried pipes, piles, or other appurtenances G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 6-1 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 76 of 230 ED 002061 00172725-00076 Go to Table of Contents j C h a p t e r 6. D e s ig n in g a D a m in A l a s k a G u id e lin e s fo r C o o p e r a t io n w ith the A laska D a m Safety Program Sierra Club v. EPA 18cv3472 NDCA 6-1 2 Tier 10 R evisio n 1 June 3 0 ,2 0 0 5 Attachment F Page 77 of 230 ED 002061 00172725-00077 Go to Table of Contents Guidelines for Cooperation with the A laska Dam Safety Program Chapter 7 CONSTRUCTING THE DAM 7.1 Preconstruction Plans................................................ 7-1 7.1.1 Water Diversion Plan....................................... 7-1 7.1.2 Erosion Control Plan........................................ 7-2 7.2 Construction Quality Assurance/'Quality Control 7-2 7.2.1 Definitions......................................................... 7-2 7.2.2 Level of CQA and CQC............. ...................... 7-3 7.2.3 Key Inspection Items........................................ 7-3 7.2.4 Design Changes....... ..................................... 7-4 7.3 Post-Construction Submittals................................... 7-4 7.3.1 Construction Completion Report......... .......... 7-4 7.3.2 Record Drawing's.............................................. 7-5 7.3.3 Operation and Maintenance Manual............. 7-5 7.3.4 Emergency Action Plan................................... 7-5 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 78 of 230 ED 002061 00172725-00078 Go to Table of Contents Chapter 7 CONSTRUCTING THE DAM In this chapter: > Details for subm ittals required before construction actually begins > Requirements for CQA/QC based on the hazard potential classification > Details fo r subm ittals required after construction is complete The proper construction of a dam is critical to the short- and long-term safety of the dam. Once a Certificate o fApproval to Construct a Dam has been issued by Dam Safety, construction may proceed. However, the communication and cooperation among the various parties must con tinue. This chapter outlines the regulatory communication that must occur during the construction period. 7.1 Preconstruction Plans The additional plans described in the subsections below may be required before construction can begin, even though a Certificate of Approval to Construct a Dam may be issued. The required plans will typically be listed as a condition to the certificate of approval because these plans are often developed by the construction contractor. 7.1.1 Water Diversion Plan The water diversion plan is required to control surface water during construction. The plan contents must address the following elements: Design drawings and specifications for cofferdams, spillways, conduits, or other temporary features that may be required to control the water Stability analysis of the cofferdam, both in normal and probable flood condi tions, with supporting hydrologic data Hydraulic and stability analyses for conduits, spillways, or other temporary features used for diversion during construction Control and pumping of seepage during construction After construction is complete, removal of cofferdams, conduits, spillways, or other temporary structures used for water diversion during construction Generally speaking, these plans should be developed by the contractor based on limited information supplied by the engineer. The engineer must consider water diversion planning during the design. The design storm for the construction period, including the estimated G u id e lin e s f o r C o o p e r a t io n w ith the A laska D a m Safety Pro g ram Sierra Club v. EPA 18cv3472 NDCA 7-1 Tier 10 R evisio n 1 June 3 0 ,2 0 0 5 Attachment F Page 79 of 230 ED 002061 00172725-00079 Go to Table of Contents C hapter 7. C onstructing the Dam volume or flow rate that must be managed during construction, should be clearly specified. The contractor should be allowed the flexibility to develop the methods and means to divert the water in coordination with other aspects of the construction, but the safety of the diversion must be ensured. In any case, the water diversion plan must be prepared in advance of construction and submitted to Dam Safety for review, as indicated in the certificate of approval 7.1.2 Erosion Control Plan The erosion control plan should include a description of measures used during and after construction to lim it erosion both within the site and the downstream channel in the vicinity of the construction. 7.2 Construction Quality Assurance/Quality Control The purpose of this section is to define terminology associated with CQA and construction quality control (CQC), indicate the level of CQA/QC that should occur based on the hazard potential classification of the dam, discuss key inspection points for the CQA/ QC inspectors and engineers, and provide guidance on design changes that may occur during construction. 7.2.1 Definitions For purposes of this guidance document and the ADSP, the following definitions are used: Construction quality assurance (CQA) - Actions taken by the owner or operator of the dam, including retaining a qualified engineering consultant (if required), to ensure that the project is completed by the construction contractor in accordance with the approved plans and specifications. These actions may include approving construction materials, conducting independent field and laboratory testing, inspecting the work during and after construction, surveying, and documenting the construction process. Construction quality control (CQC) - Actions taken by the construction contractor to control the quality of work to meet the requirements of the approved plans and specifications. These actions may include surveying, borrow pit investigations, field and laboratory materials testing, construction methodology, scheduling, and documentation. CQA or CQC plan - A formal document that outlines the scope of the activity to be conducted during construction to control or assure the quality of the finished project. A CQA/QC plan that includes the requirements for both CQA and CQC may be developed, but the responsibilities for specific work must be clearly delineated. The scopes of the CQA and CQC plans depend on the complexity and hazard potential classification of the dam. Guidance on the recommended contents of these plans is beyond the scope of these guidelines. However, a CQA/QC plan is required under 11 AAC 93.171(f)(3)(D). Dam Safety will review the contents of the plan under the Detailed Design Package. (See Section 5.3.4.) A draft submittal is recommended. Third-party CQA - A CQA provided by an engineering consultant, independent from the owner or the contractor, who is qualified in the construction inspection of the type of dam CU IDELIN ES FOR C O Q PERATiO N WITH THE A l a s k a D a m S a f e t y P r o g r a m Sierra Club v. EPA 18cv3472 NDCA 7-2 Tier 10 R evisio n 1 June 3 0 ,2 0 0 5 Attachment F Page 80 of 230 ED 002061 00172725-00080 Go to Table of Contents C hapter 7, C onstructing the Da m and appurtenant works under construction. The third party could be the engineering design consultant. Construction Inspection Engineer - According to 11 AAC 93.173(c)(2), except for the removal or abandonment of a Class III (low) hazard potential dam, a qualified engineer is required to "observe and inspect the work for compliance with the approved plans, drawings, and specifications." The construction inspection engineer is responsible for the CQA activities described above, the key inspection items discussed in Subsection 7.2.3, and preparation and certification of the construction completion report and record drawings described in Section 7.3. 7.2.2 Level of CQA and CQC Table 7-1 indicates the general level of CQA/QC that is required based on the hazard potential classification of the dam. Table 7-1. C Q A /Q C Levels Based on Hazard Potential Classifications R e q u ire d Level o f C Q A /Q C CQA pian CQC pian Owners CQA Third-party CQA CQC Engineering inspection I Yes Yes Optionai Yes Yes Yes Hazard Potential C lassification II Yes Yes Yes Optional Yes Yes 111 Optional Yes Yes Optional Yes Yes 7.2.3 Key Inspection Items The design engineer should iden tify key inspection items for various aspects of construction based on the type of dam and its hazard potential classification. Some of these items must be inspected before additional work may proceed; for example, the foundation must be inspected before any fill is placed, or rebar may need inspection before concrete is poured. These items must be clearly identified in the construction specifications as mandatory inspection points so that the contractor can make appropriate allowances. Other key inspection items, such as fill compaction or concrete testing, may occur over time. All key inspection items that are critical to the design or could affect the contractor should be clearly indicated in the construction specifications or on the final construction drawings. These inspections must be conducted by the construction inspection engineer (as discussed in Subsection 7.2,1), the engineer of record, or another engineer or geologist under the supervision of the construction inspection engineer or the engineer of record. Guidelines for C ooperation with the A laska Dam Safety Program Sierra Club v. EPA 18cv3472 NDCA 7-3 Tier 10 Re v isio n ! June 30, 2005 Attachment F Page 81 of 230 ED 002061 00172725-00081 Go to Table of Contents C hapter 7. C onstructing the Dam 7.2.4 Design Changes All design changes that are proposed after a Certificate ofApproval to Construct, Modify, or Repair a Dam is issued must he reviewed by Dam Safely. In some cases, depending on the nature of the proposed change, additional submittals may be required and written approval may need to be obtained from Dam Safety before the change is implemented. In all cases, the design change must be approved in writing by the engineer of record who certified the design. 7.3 Post-Construction Submittals The following post-construction documents must be submitted to Dam Safety after completion of the dam construction, modification, or repair. 7.3.1 Construction Completion Report A construction completion report is required for Class I, II, and HI dams. The scope of the construction completion report will depend on the complexity of the project. The report content should include the following: Description of how the plans and specifications were followed or deviated from, including the types of materials used for construction, brand names or catalog sheets of components, and other descriptive information Description of unexpected conditions encountered Inspection reports Field and laboratory test results, including sample locations and test standards or methodologies Photographs documenting construction progress and final conditions Seal and signature of the construction inspection engineer defined in Subsection 7.2.1 Record drawings, as described in Section 7.3.2 Submittal Standards One copy of the completion report should he submitted. _____________________________________ Before Filling the Reservoir The post-construction submittals must be approved by D am Safety before a Certificate o f Approva! to Operate a Dam is executed. No impoundment may occur until this certificate is issued. For modified dams, im poundm ent m a y be restricted to a certain elevation until this certificate is issued. In some cases, a first fill pian m ay be required based on guidance from the design engineer. The plan m ay specify the maximum rate of filling and a temporary monitoring schedule. A first fill incident report m ay be requested. (See Chapter 11). G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 7-4 Tier 10 Revision 1 June 30, 2005 Attachment F Page 82 of 230 ED 002061 00172725-00082 Go to Table of Contents C hapter 7, C onstructing the D am 7.3.2 Record Drawings Record drawings are mandatory for Class I, II, and III dams. These drawings must contain a complete record of the construction, including actual elevations, changes in major design components or details, and appurtenant construction. Submittal Standards One copy of final record drawing package should he submitted. Drawings that are 11 inches by 17 inches are acceptable if they are legible and to scale (no offscale reductions). Larger drawings should he submitted if necessary for clarity. Drawings should include the following: Seal and signature of the construction inspection engineer defined in Subsection 7.2.1 Stamp or mark on all drawings stating "Construction Record Drawing" or similar language Current revision number and date 7.3.3 Operation and Maintenance Manual An O&M manual is mandatory for Class I, II, and III dams to receive a Certificate of Approval to Operate a Dam. Details about the O&M manual are provided in Chapter 8. 7.3.4 Emergency Action Plan An EAR is mandatory for Class I and II dams. For new construction, this plan must be included with the post-construction submittals to receive a Certificate of Approval to Operate a Dam. Details about the EAP are provided in Chapter 9. Guidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 7-5 Tier 10 Revisio n ! June 30, 2005 Attachment F Page 83 of 230 ED 002061 00172725-00083 Go to Table of Contents C hapter 7. C onstructing the D am G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 7-6 Tier 10 Revision 1 June 3 0,2005 Attachment F Page 84 of 230 ED 002061 00172725-00084 Go to Table of Contents Guidelines for Cooperation with the A laska Dam Safety Program Chapter 8 OPERATIONS AND MAINTENANCE PROGRAM 8.1 Operations and Maintenance Manual........... .....................................................................8-1 8.2 Monitoring............................................................................................................................. 8-2 8.3 Operator Training Program.......... ..................................................................................... 8-3 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 85 of 230 ED 002061 00172725-00085 Go to Table of Contents Chapter 8 OPERATIONS AND MAINTENANCE PROGRAM In this chapter: > Requirements fo r O&M planning and an O&M manual > Monitoring requirements for dam s based on hazard potential classification > Recommendations and references for dam operator training Next to proper design and construction, O&M planning is the most important aspect of an owner's commitment to the safety of the dam. Because of the importance of O&M planning, Dam Safety will not issue a Certificate o fApproval to Operate a Dam. for a dam of any classification until an O&M manual is submitted by the dam operator, important aspects of O&M planning are discussed in additional detail in the following sections. The following is a useful resource for O&M planning: Training Aids for Dam Safety Module: How to Organize an Operation and Maintenance Program, published by the USBR (1990) This useful document defines an "O&M program" as "a systematic means of ensuring that a dam is operated and maintained adequately ... for ensuring the continued safe operation of the dam [and] the continued productive use of the reservoir." As mentioned in Section 1.3, it is the responsibility of the owner and operator of the dam to ensure that an O&M program for the dam and all appurtenances is properly developed and funded for the life of the facility. 8.1 Operations and Maintenance Manual Proper O&M is crucial for darns and reservoirs to operate safely and efficiently. An O&M manual is an essential component of the O&M program that describes procedures for operating the dam under normal and extreme reservoir level and flow conditions. It also provides technical guidance and procedures for monitoring, inspection, and long-term maintenance programs. The complexity of the O&M man ual is highly dependent on the complexity of the dam and its related features. The O&M manual should be presented as simply as possible, however, so that it is easy for the operator to understand its contents and implement its requirements. According to 11 AAC 93.197, the O&M manual must describe in detail how a dam will be operated, inspected, and maintained. Required components include the following: Physical description of the dam CUIDELINES FOR COQPERATION WEEH the A laska D a m S a f e t y P r o g r a m Sierra Club v. E P A 18cv3472 N D C A 8- Tier 10 Revision 1 June 3 0,2005 Attachment F Page 86 of 230 ED 002061 00172725-00086 Go to Table of Contents C hapter 8. O perations a n d M aintenance Program Any operating limitations on the dam Critical design criteria, including the Project Data Sheet (See Appendix D.) Schedule and procedures for routine safety inspections, monitoring, and maintenance of the dam Detailed instructions and maintenance procedures for operating valves, gates, or other equipment Maintenance procedures, calibration information, and instructions for instrumentation and for monitoring and alarm systems Site-specific visual inspection checklists and monitoring data collection forms Other information requested by Dam Safety to provide sufficient detail about dam operation, inspection, and maintenance for the protection of life and property In addition, Dam Safety recommends that O&M manuals contain descriptions of unusual conditions tirt are most likely to occur at the dam and the operating procedures that should occur under those conditions, including extraordinary inspections (see Section 10.3) and incident reporting as required by 11 AAC 93.177 (see Chapter 11). The O&M manual and actual practices should be consistent. Organiza tions such as municipal public works departments that use computerized O&M task managers should incorporate the requirements of the O&M manual for the dam into the system. An O&M manual should be reviewed on a regular basis and upda ted as necessary. The manual must he titled and dated and should include revision numbers for accurate reference. A record of revisions should be included. Appendix E contains a sample outline for a simple O&M manual. Additional guidance is available in the previously cited reference (USER, 1990). 8.2 Monitoring Monitoring equipment, procedures, and instrumentation may be required to accomplish the following: Confirm that the structure is performing in accordance with the design Determine if a problem exists that may require remediation Provide timely notice of an adverse change in the state of the dam or reservoir Oranges in seepage character, abnormal settlement patterns, and slope movements are often symptoms of deterioration in the embankment and foundations. Unusually high water levels can indicate an immediate problem is developing. Baseline monitoring is critical to determine whether change is occurring. Instrumentation must be combined with responsible recording and analysis of the data to identify significant trends in the performance of the dam. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 8-2 Tier 10 Revision 1 June 3 0 ,2005 Attachment F Page 87 of 230 ED 002061 00172725-00087 Go to Table of Contents C hapter 8. O peratio n san d Maintenance Program The following are key elements of a successful monitoring plan: An O&M manual that requires the diligent implementation of the observation and data collection procedures The timely analysis and evaluation of inspection records and data for significant changes or adverse trends in anticipated behavior Procedures in the O&M manual to follow when monitoring indicates significant changes or unusual conditions are occurring Effective tools for monitoring the condition of a dam include the following: Visual inspection checklists with comments Photographs of key features taken from a consistent perspective over time Automatic data loggers connected to critical instrumentation Alarm systems connected to full-time monitoring devices such as water level indicators Internal review procedures to ensure that monitoring data are properly evaluated Table 8-1 recommends minimu m levels of monitoring and instrumentation based on the hazard potential classification of the dam. Table 8-1. Suggested Monitoring and Instrumentation Levels Monitoring Item Routine visual inspection checklist Reservoir staff gauge Water levei data loggers Water level alarms Precipitation gauge Settlement/displacement indicators Seepage/under-drain weirs Piezometers Thermistors Hazard Potential Classification i li ill Yes Yes Yes Yes Yes Yes Yes Optional Yes Optional Yes Optional Yes Yes Yes Yes Yes Yes Yes Yes Note: Specific monitoring and instrumentation should be based on an engineering evaiuation of the dam. For example, strain gauges or crack monitors may be required on a Class i concrete dam. 8.3 Operator Training Program The owner and operator of a dam are responsible for understanding all technical aspects of the system that are necessary to operate the dam in a safe manner. A training plan should be included in the O&M program to provide employees with the proper expertise that will enable them to perform their respective duties. Training should be required initially for new CUIDELINES FOR COOPERATIQN WITH THE A laska Dam Safety Procram Sierra Club v. E P A 18cv3472 N D C A 8-3 Tier 10 Revision 1 June 3 0 ,2 0 0 5 Attachment F Page 88 of 230 ED 002061 00172725-00088 Go to Table of Contents C hapter 8. O perations a n d M aintenance Program employees and recurrently for all employees during the life of the project, as appropriate. Training should be progressive so that it will cover the wide variety of topics typically associated wi th opera tion, maintenance, inspection, and monitoring of darns. The following training references, listed by source, are highly recommended by Dam Safety: Training Aids for Dam Safety (TADS) - TADS is a comprehensive collection of notebooks and videos published by the USER. TADS modules are available for these and other topics: Dam Safety Awareness Identification of Visual Dam Safety Deficiencies Inspection of Embankment Dams Inspection of Concrete and Masonry Dams Inspecting and Testing of Gates, Valves, and Other Mechanical Systems Inspection of Spillways and Outlet Works Evaluation of Seepage Conditions Documenting and Reporting Findings from a Dam Safety Inspection Contact the USER in Denver Colorado at (303) 236-4308 or (303) 236-2946 for ordering informa tion. Association of State Dam Safety Officials - ASDSO is a national, nonprofit organization that promotes dam safety on behalf of its members, which consist of state and federal agencies, dam owners and operators, engineering consultants, contractors, vendors, research institutes, and others. ASDSO sponsors regional and national training seminars and conferences on an annual basis. Special training programs, including workshops specifically geared toward dam owners and operators, can be scheduled. The ASDSO Web site includes news, an on-line bibliography and bookstore, and links to numerous other dam-related Web sites. Membership in ASDSO is encouraged by Dam Safety. For more information, contact ASDSO in Lexington, Kentucky, at (859) 257-5140 or visit the organization's Web site at www.damsafety.org. Alaska Dam Safety Program Library - The ADSP maintains a limited library of information that is available for loan to dam owners, operators, engineering consultants, and students in Alaska. The library houses the following relevant training materials: Complete TADS modules, including notebooks and videotapes Publications from the U.S. Society of Dams (USSD) (formerly USCOLD) Interagency Committee on Dams (ICODS) training videos published by the National Dam Safety Program Select ASDSO regional and annual conference proceedings since 1999 G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 8-4 Tier 10 Revision 1 June 3 0 ,2 0 0 5 Attachment F Page 89 of 230 ED 002061 00172725-00089 Go to Table of Contents C hapter 8, O perations a n d M aintenance Program Miscellaneous design and operation guidance published by agencies such as the FEMA, FERC, , USAGE, USER, WSDOE, and Portland Cement Association Classic textbooks such as Design o f Small Dams (USER, 1987), Handbook o f Dam Engineering (Golze, 1977), and Seepage, Drainage, and Flow Nets (Cedergren, 1989) G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 8-5 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 90 of 230 ED 002061 00172725-00090 Go to Table of Contents | C h a p t e r 8, O p e r a t io n s a n d M a in t e n a n c e P r o g r a m G uidelines for C oopration with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 8-6 Tier 10 Revision 1 June 3 0,2005 Attachment F Page 91 of 230 ED 002061 00172725-00091 Go to Table of Contents Guidelines for Cooperation with the -- , Alaska Dam Safety Program Chapter 9 EMERGENCY ACTION PLANNING 9.1 Emergency Ac tion Plans........... 9-2 9.1.1 Emergency Action Plans for Class I Dams................................................................ 9-3 9.1.2 Emergency Action Plans for Class II Dams........................................................... 9-4 9.2 Emergency Action Flan Exercises........................................................................................ 9-4 9.3 Dam Failure Analysis............................................................................................................ 9-5 9.3.1 Preliminary.................................................................................................................... 9-6 9.3.2 Qualitative..................................................................................................................... 9-6 9.3.3 Quantitative......... .........................................................................................................9-6 9.3.4 Guidance on Dam Failure Analysis........................................................................... 9-7 9.4 Inundation Maps................ 9-10 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 92 of 230 ED 002061 00172725-00092 Go to Table of Contents Chapter 9 EMERGENCY ACTION PLANNING In this chapter: > Discussion o f the purpose, form at, and content o f EAPs fo r Class I and II dams > Descriptions o f EAR exercises > Guidelines for conducting a dam failure analysis Dam failures can have devastating impacts on people and property. For these reasons, it is vital to be prepared in advance of an emergency situation. An EAP prepared by the dam owner is required by 11 AAC 93,164, 93.167, and 93.171 for Class 1 and II dams. This section describes the purpose and requirements for an EAP, outlines the EAP contents based on the hazard potential classification, recommends EAP exercise levels and schedules, and provides guidance on dam failure analysis. The following are purposes of the EAP: Protect lives and property if an emergency condition develops at a dam Prepare owners, operators, and emergency management personnel for the emergency event, in advance Detail the actions and measures that will be taken by all parties that are responsible for responding to an emergency Facilitate the coordination and cooperation of the various emergency responders An emergency condition is assumed to exist if either of the following conditions exist: An impending or actual release of water, mine tailings, or other substances caused by improper operation, accidental damage, sabotage, or general failure of a darn, penstock, or other appurtenances An impending flood condition, even when the dam is not in danger of failure These conditions may develop slowly or occur suddenly. Emergency action planning in advance is the only way to be prepared. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 9-1 Tier 10 Revision 1 June 3 0,2005 Attachment F Page 93 of 230 ED 002061 00172725-00093 Go to Table of Contents C hapter 9. Emergency A ction Planning 9.1 Emergency Action Plans The regulations in 11 AAC 93.164(b) identify the following specific requirements for an EAP for Class I and II dams regulated under the ADSP: Adequately protects life and property, given the particular risks to the life or property if the dam fails or in anticipation of darn failure Provides adequately for coordination of emergency responders in the community Contains information that Dam Safety considers necessary to minimize danger to life and property, which may include these components: Detailed inundation map (See Section 9.4.) Dam break analysis (See Section 9.3.) Schedule for exercise and revision of the plan (See Section 9.2.) Review of the EAP at least annually and submittal of any revisions to Dam Safety for approval Exercise of the EAP to a level specified by Dam Safety to maintain adequate preparation for an actual emergency Revision of the EAP after exercise to address any areas needing improvement Distribution of revised EAPs to all persons with responsibilities identified in the EAP Revision of the EAP at least every three years or as determined by Dam Safety as sufficient to maintain adequate preparation for an actual emergency The following are general recommendations for all EAPs: Simple, effective, and user-friendly content Site-specific information reflecting realistic anticipation of the most likely emergency conditions or failure scenarios for the dam Clearly identified potential impacts of a dam failure, including nonfailure-related flooding; Clearly identified potentially affected parties Clearly outlined responsibilities of the emergency responders Availability to and ability to be understood by all emergency response personnel involved, including dam operators; local, state, and federal emergency response agencies; and other parties with responsibilities listed in the plan Identification that includes site-specific title, date, and revision number Submittal in both paper and electronic (Adobe) formats G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 9-2 Tier 10 Revision 1 June 3 0,2005 Attachment F Page 94 of 230 ED 002061 00172725-00094 Go to Table of Contents C hapter 9. Emergency A ction Planning 9.1.1 Emergency Action Plans for Class I Dams The regulations in 11 AAC 93.164(b)(4) specifically require the development and maintenance of the EAP for Class I dams in general accordance with either of the following: Federal Guidelines far Dam Safety: Emergency Action Planningfar Dam Owners (FEMA, 1998c) Other requirements determined by Dam Safety to be necessary to protect life or property The format recommended by the FEMA is consistent with guidance provided by the FERC. This format is adopted by the ADSP to promote consistency for emergency managers who may be responsible for responding to dams owned by different entities, even in a single community. Alternative formats may be acceptable for use in matching local emergency response plans for general emergencies. Any alternative formats must be specifically approved by Dam Safety. The following format promoted by the FEMA is recommended for Class I dams: Title Page/Cover Sheet Table of Contents I. Notification Flowchart II. Statement of Purpose III. Project Description IV. Emergency Detection, Evaluation, and Classification V. General Responsibilities Under the EAP VI. Preparedness VII. Inunda tion Maps VIII. Appendices A. Investigation and Analysis of Dam Break Flood B. Plans for Training, Exercising, Updating, and Posting the EAP C. Site-Specific Concerns D. Approval of the EAP Specific guidance on select aspects of the EAP follows. Notification flowcharts - The content of these flowcharts is determined by the magnitude of the anticipated failure and the number of emergency response personnel or agencies identified in the plan. A flowchart should be prepared for the following scenarios: A non-failure emergency condition A potential failure situation developing An imminent or actual failure in progress Each flowchart should clearly indicate priority notifications for emergency initiators and delegation of responsibilities for secondary and tertiary notifications. Poten tial victims G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 9-3 Tier 10 Revision 1 June 3 0,2005 Attachment F Page 95 of 230 ED 002061 00172725-00095 Go to Table of Contents C hapter 9. Emergency A ction Planning that require immediate notification should be included, and locations of detailed lists of other potential victims should be referenced. Inundation maps and dam break analysis - See Section 9.3 and 9.4 for more detailed information. Topographical maps are not required for inundation maps, even though they are used to analyze dam-failure scenarios. Plans for training, exercising, updating, and posting the EAP - Training related to the EAP should be included in the training plans of the dam owner and operator, as recommended in Section 8.3. The EAP should he reviewed annually for current contact information, applicability, and other concerns and should be revised as needed. The EAP should also be revised to reflect improvements identified through exercises, comments from responsible parties, and actual emergency events. Exercises should be conducted regularly. The following levels and frequencies of exercises are recommended: Orientation exercise (all responsible parties) - annually Drill exercise (darn operator only) - annually Tabletop exercise (all responsible parties) - every three years Functional exercise (all responsible parties) - upon request of Dam Safety for Class 1 dams Additional detailed guidance on EAP exercises is provided in Section 9.2 9.1.2 Emergency Action Plans for Class II Dams Because there is a low probability for loss of life associated with a Class II dam, Dam Safety is inclined to allow some flexibility in the scope of the EAP. For Class II dams, the EAP may be included in the O&M manual or in a site emergency operations plan. The requirements and recommendations indicated in Section 9.1 still apply, as appropriate. 9.2 Emergency Action Plan Exercises According to 11 AAC 93.164, the owner is responsible for exercising the EAP. The dam owner and operator should develop and implement the policies and programs to ensure that the EAP is properly exercised on a regular basis. The schedule for EAP exercises is typically included as a condition to the Certificate o f Approval to Operate a Dam, as indicated in the example certificate presented in Appendix B, The FEMA (1998c) recommends five types of exercises that can he included as part of the exercise program. The various levels of exercises (ranging from simplest to most complicated) are identified below: Orientation seminar - Involves bringing together individuals with a role or interest in the EAP to discuss the EAP and initial plans for an annual drill or more in-depth exercises Drill - Tests and develops the skills of the dam operator to respond in an emergency situation G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 9-4 Tier 10 Revision 1 June 3 0,2005 Attachment F Page 96 of 230 ED 002061 00172725-00096 Go to Table of Contents C hapter 9, Emergency A ction Planning Tabletop exercise - involves a meeting of dam operator and emergency management officials in a conference room environment. A simula ted event is described and the respective actions of each participant are discussed. Functional exercise - Involves a stress-induced environment with time constraints in a controlled setting wherein participants must respond to a simulated dam failure and other specified events Full Scale exercise - includes field mobilization and movements as participants "play out" their roles in a dynamic and open setting that provides a high degree of realism These exercises are described in detail in FEMA (1998c) and FERC guidance (2000). In addition, the FERC also provides guidance on designing an EAR exercise. Dam Safety can also be contacted for assistance in planning EAR exercises, and will attend and participate in exercises whenever possible. Except under special circumstances, Dam Safety will not typically require a functional or full-scale exercise. 9.3 Dam Failure Analysis A conservative understanding of the potential impacts of a dam failure is critical to the mission of the ADSP. An evaluation of a hypothetical dam failure is the process that is used to assign the hazard potential classification; however, a detailed and accurate dam failure analysis is a complex and expensive engineering endeavor that may only be required under certain circumstances. As discussed in Section 2.4, Dam Safety recognizes three levels of dam failure analyses for determining the hazard potential classification. The circumstances for which these levels of evaluation may be appropriate are outlined below. Preliminary Initial assignment of hazard potential classification for discussion purposes Class III (low) assignment for rural water supply, sanitary waste, or hydroelectric dams with no development downstream and no anadromous fish Initial Class I assignment for large dams or reservoirs upstream from highly developed areas initial Class II assignment to mine tailings dams that meet the geometric parameters that define a dam as discussed in Section 2.3, a dam loca ted on an anadromous fish stream, or a primary water supply dam for a community with 500 or more residents Conservative assignment of classification under which all parties agree to comply with the respective requirements Qualitative Disputed hazard classification assignments for which limited development exists downstream and a technically sound, qualitative review results in a conservative conclusion Guidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 9-5 Tier 10 Rev isio n ! June 30, 2005 Attachment F Page 97 of 230 ED 002061 00172725-00097 Go to Table of Contents C hapter 9. Emergency A ction Planning Quantitative Disputed hazard classification assignments for which a qualitative analysis does not result in a conservative conclusion Dispu ted hazard classifications for which compliance with the conservative assignment results in substantial economic burdens on the dam owner and the most accurate analysis is justified Certain systems for which the results of a dam failure are not apparent, such as a relatively large dam or reservoir located a long distance upstream from a development that may not be in an apparent floodplain For emergency action planning of Class I or II dams if development of an inundation map requires detailed flood stage, flood wave travel times, or duration and quantity of flooding from the improper operation or failure of the dam General guidance on conducting a dam failure analysis for each level of review is included in the following subsections. Specific guidance on dam failure analyses is presented in Subsection 9.3.4. 9.3.1 Preliminary A preliminary dam failure analysis is based on a review of limited information about the dam and the downstream system. This information may include a visual inspection of the dam, reservoir, and the downstream reach; conceptual design drawings; and other limited, readily available information such as aerial photography and topographic maps. The primary basis for the analysis is engineering judgment. 9.3.2 Qualitative A qualitative dam failure analysis is a limited engineering evaluation that may involve rudimentary hydrological estimates; simplistic calculations to estimate the peak discharge from a dam failure such as weir equations or graphical solutions; open-channel flow calculations at discrete cross sections along the downstream channel near the development; elevation or crosssection surveys; and other simplistic data used with conservative assumptions. Useful information for conducting a qualitative dam failure analysis is included in the "Dam Break Inundation Analysis and Downstream Hazard Classification," Technical Note 1, of the Dam Safety Guidelines published by the WSDOE (1992). 9.3.3 Quantitative A detailed dam failure analysis that includes a computerized dam breach and hydra ulic routing model, detailed hydrological estimates, and good-quality input data is considered a quantitative analysis. Although this level of engineering carries the greatest level of credibility in the scale of dam failure evaluations, a numerical evaluation is subject to the old compu ter axiom "Garbage in equals garbage out." A computerized dam break analysis that uses gross assumptions does not carry the same credibility as an analysis in which input data are detailed and verifiable, but may be more credible than a qualitative analysis. Such input data may be G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 9-6 Tier 10 Revision 1 June 3 0 ,2 0 0 5 Attachment F Page 98 of 230 ED 002061 00172725-00098 Go to Table of Contents C hapter 9. Emergency A ction Planning derived from field surveys, site-specific hydrological analysis, as-built construction drawings, laboratory testing, or other relatively high quality data. In other words, the higher level of engineering detail contributes to the grea test level of understanding about the most likely effects of a dam failure. For any quantitative dam failure analysis, all methodologies, assumptions, data sources, and references must be clearly documented. Dam Safety recommends the most current versions of following models developed by the USAGE for a quantitative dam failure analysis: HEC-HMS by the USAGE HEC-RAS by the USAGE These models are Windows-based compu ter programs that are current, modern, and sophisticated. HEC-HMS is a hydrologic model that includes dam breach subroutines and generates a dam-break flood hydrograph. HEC-RAS is a hydraulic model that routes the dambreak flood hydrograph downstream. Other computer models that may be used for a quantitative analysis include the following: HEC-1 published by the USAGE DAMBRK published by the National Weather Service, most recently in 1992 FLDWAV published by the National Weather Service in 1997 The application of any of these programs should be specifically discussed with Dam Safety before they are used for modeling. 9.3.4 Guidance on Dam Failure Analysis A darn failure analysis at any level should consider the following: Hydrologic Conditions Sunny day dam break - Assumes that the dam fails with the reservoir level, inflow, and discharge at normal operating levels Flood stage dam break - Assumes the dam fails with the reservoir and spillway discharge at maximum capacity, and flooding is occurring based on the 100-year flood or on some percentage of the probable maximum flood or another technically justifiable value such as the IDF Guidance from an Expert For detailed guidance on dam failure analysis, see the DV D "Dam Breach and Flood Wave Modeling"by Dr. Danny L. Fread, published in 2004 by the interagency Committee on Dam Safety, the U S. Bureau of Reclamation, and FEMA. Copies are available from ASDSO. In some cases, an incremental damage assessment may be required to determine the point at which the additional flooding that occurs from the failure of the dam is insignificant. An incremental damage assessment should be conducted in accordance with Evaluation Procedures for Hydrologic Safety o f Dams published by the American Society of Civil Engineers (1988). G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 9-7 Tier 10 Revision 1 June 30, 2005 Attachment F Page 99 of 230 ED 002061 00172725-00099 Go to Table of Contents C hapter 9. Emergency A ction Planning Failure Mode and Configuration The dam failure analysis should consider the mode in which the dam is most likely to fail The modes to be considered for select types of dams follow: Embankment dams - Breach caused by overtopping or piping failure Concrete gravity dam - Displacement of at least one full monolith Concrete arch dam - Displacement of full width of arch Timber frame dams - Complete destruction of face between two spans of bents Timber cribbing dams - Full breach as indicated in Table 9-1 Acceptable values for the breach configuration are included in Table 9-1. Dam breach software such as BREACH (Fread, 1987) may be required for a quantitative analysis. A detailed failure mode and effects analysis may he required for complex, Class I (high) hazard dams. Dam Safety can be contacted for additional information. Table 9-1. Acceptable Dam Breach Parameters Type o f D am A verage Breach W idth (feet) Breach Side Slope; R atio Horizontal: Vertical T im e to Failure (hours) Arch Crest length 0:1 (vertical) to slope less than 0.1 of valley wall Buttress Multiple slabs 0:1 (vertical) 0.1 to 0.3 Masonry, gravity monoliths Width of one or more sections 0:1 (vertical) or monoliths, usuaily less than one-half crest length 0.1 to 0.3 Rock fill Height of dam to 5 times height of dam 0.25:1 to 1:1 0.1 to 1.0 Timber crib 2 to 4 times height of dam 0:1 (vertical) 0.1 to 1.0 Earthen (non-engineered) 2 to 5 times height of dam 0.25:1 to 1:1 0.1 to 0.5 Earthen (engineered) 0.5 to 5 times height of dam 0.25:1 to 1:1 0.1 to 1.0 Comments: Average breach width depends on cross-sectional shape of breach and is not necessarily the bottom width. Shape of breach is less critical than average width of breach. Time to failure is a function of height of dam and location of breach. The greater the height of the dam and the storage volume, the greater the time to faiiure and probably the greater the average breach width. The bottom of the breach should be at the foundation elevation. See Chapter II, Selecting and Accommodating Inflow Design Fioods for Dams, Appendix Il-A, Dambreak Studies, in the 1993 Federal Energy Regulatory Commission report Engineering Guidelines for further comments and commentary. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 9-8 Tier 10 Revision 1 June 3 0,2005 Attachment F Page 100 of 230 ED 002061 00172725-00100 Go to Table of Contents C hapter 9, Emergency A ction Planning Flood Wave Attenuation In a qualitative analysis, if the downstream channel adjacent to development wall not pass a dam break peak discharge without flooding, the peak discharge, Qp, may be attenuated, as shown in Figure 9-1 (WSDOE, 1992). The attenuated flow, Qx, at the location of the development at a distance, x miles downstream, is compared to the channel capacity at the development. If flooding occurs, cross-section and elevation surveys or a more detailed evaluation such as a quantitative analysis may be required. In either qualitative or quantitative analyses, the area downstream of the dam must be considered to a distance at which the flood wave is attenuated sufficiently so that the effects of the increased flow are inconsequential. Effects on Important Fish Habitat In some cases for Class II dam s in which potential dam age to important fish habitat m ay occur, erosion and scour damage or sedimentation m ay need to be considered, even if the channel capacity is adequate or flooding is otherwise irrelevant. Multiple Dams The domino effects of a dam failure on dams located downstream must be taken into account. If the failure of the dam under review would cause the failure of a dam downstream, the value of that structure must be considered in the hazard potential classification of the upstream dam. Furthermore, the combined failure of the two dams must be considered. In other words, the upper dam must at least carry the hazard potential classification of the lower dam, and could carry an even higher classification if the impacts of the combined failure are significantly greater than the failure of the lower dam alone. Figure 9-1. Attenuation of Flood Peak Following a Dam Break Source: W SDO E, 1992 G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA DISTANCE DOWNSTREAM piles) 9-9 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 101 of 230 ED 002061 00172725-00101 Go to Table of Contents C hapter 9. Emergency A ction Planning If the upstream dam could fail without adversely affecting the lower dams, the hazard potential classification of the upstream dam may be determined based on an independent dam failure analysis of the upstream dam. In this case, the attenuating affects of downstream reservoirs may be included in the analysis. 9.4 Inundation Maps Inundation maps should be good-quality graphic illustrations that use current maps or aerial photographs. Although topographic maps may be required for a dam break analysis and for developing an inundation map, topography is not a required component of the inundation map in an EAP because the additional lines may reduce the legibility. Regulations in 11 AAC 93.195 indicate that the map should be prepared on the basis of a dam break analysis, if required, and should identify the following information: Extent of flooding below a dam after failure under the following conditions: Normal operating level of the reservoir Inflow design flood Other scenarios that Dam Safety considers necessary to evaluate danger to life and property Downstream structures or other development at risk Flood wave depth and arrival times Roads, evacuation routes, safe zones, and staging areas Other information required by Dam Safety to minimize danger to life and property Guidelines for C ooperation with the A laska Dam Safety Program Sierra Club v. EPA 18cv3472 NDCA 9-10 Tier 10 Revision June 30, 2005 Attachment F Page 102 of 230 ED 002061 00172725-00102 Go to Table of Contents Guidelines for Cooperation with the Alaska Dam Safety Program Chapter 10 INSPECTIONS 10.1 Construction Inspections.................................................................................................. 10-1 10.2 Routine* Inspections .......................................................................................................... 10-1 10.3 Extraordinary Inspections................................................................................................ 10-2 10.4 Periodic Safety Inspections............................................................................................... 10-3 10.4.1 Guidance on Cond ucting- the PSI........................................................................... 10-4 10.4.2 Scope of the PSI......................................................................................................... 10-6 10.4.3 Format of PSI Report.................................................................................................10-7 10.5 ADNR Field Inspections................................................................................................... 10-8 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 103 of 230 ED 002061 00172725-00103 Go to Table of Contents Chapter 10 INSPECTIONS In this chapter: > Description o f five types o f inspections associated with dams > Detailed description o f the PSI review process > Guidance on conducting a PSI and on the form a t o f the PS! report Inspecting the dam on a regular basis during construction and operation is critical to ensure the safety of the dam during the life of the project. The ADSP recognizes five types of inspections: Construction inspections conducted during the construction of the dam by a qualified engineer as defined in Tl AAC 93.193(c) (see Subsection 1.3.4) or by CQA or CQC personnel under the direct supervision of a qualified engineer Routine inspections conducted by the dam operator Extraordinary inspections conducted by dam operator Periodic safety inspections (PSI) conducted by an approved, qualified engineer as defined in 11 AAC 93.193(b) (See Subsection 1.3.4.) Field inspections conducted by Dam Safety Additional information is provided in the following sections. 10.1 Construction Inspections Construction inspections are critical for use in documenting how the dam is constructed and the conditions under which construction occurred. These inspections are typically performed by the CQA and CQC personnel, under the direct supervision of the construction inspection engineer defined in Subsections 1.3.4 and 7.2.1. Observations of construction inspectors must be documented and included in the construction records. See Section 7.2 and Subsection 7.3.1 for more information. 10.2 Routine Inspections Routine inspections are necessary for the dam operator to become familiar with normal operating conditions and to provide early warning of developing problems that can affect the safety of the dam. These inspections must be diligently conducted in accordance with the G u id e l in e s f o r C o o p e r a t io n w it h the A laska D a m Safety Pro gram Sierra Club v. EPA 18cv3472 NDCA 1 0-1 Tier 10 R e v is io n 1 June 30, 2 0 0 5 Attachment F Page 104 of 230 ED 002061 00172725-00104 Ci to Table of Contents C hapter 10. Inspections schedule specified in the O&M manual, as described in Chapter 8. The frequency of routine inspections depends on the following attributes: Hazard potential classification Type of dam Complexity and criticality of dam fea tures and appurtenances Condition of the dam Instrumentation monitoring program The frequency for routine inspections should be recommended by a qualified engineer. Routine inspections may include the following: Casual inspections such as a daily walk or drive through the facilities Recorded inspections that rely on a checklist, completed by the inspector, that includes site-specific features that can be readily observed for normal or abnormal conditions A visual inspection checklist tailored to the specific dam is recommended for recorded, routine inspections. This checklist should be short and specific to the performance parameters of the dam as identified by a qualified engineer. An example of a site-specific visual inspection checklist is included with the sample outline of an O&M manual in Appendix E, Routine inspections are conducted by staff members of the dam owner or operator trained in the unique aspects of the dam that is under review. The inspector must be familiar with visual clues that cou ld indicate a problem, as well as monitoring procedures for instrumentation that may be included in the routine inspection. The checklist is completed by the inspector and then reviewed by the inspector's supervisor. The Required Routine inspections Routine inspections m ust be conducted and recorded for aii hazard c/assification dams. The frequency for routine inspections must be specified in the O&M manuai. Visuai inspection checklists or other records must be filed and available for review upon request by Dam Safety and as part of the periodic safety inspection described in Section 10.4 checklist is then stored as a record of the routine inspection in the project file at the nearest office of the dam operator. Other methods of conducting and recording routine inspections such as PDAs or laptop computers may be acceptable. Regardless of the method used, the routine inspection and record keeping procedures must be outlined in the O&M manual. 10.3 Extraordinary Inspections Extraordinary inspections should be conducted by the dam operator whenever a situation or event occurs that could cause or indicate that a problem could be developing at the time. Extraordinary inspections should occur as a result of the following: Earthquakes G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 10-2 Tier 10 Revision 1 June 30, 2005 Attachment F Page 105 of 230 ED 002061 00172725-00105 Go to Table of Contents C hapter 10. Inspections Heavy or extended precipitation Suspected or reported vandalism Increased threat levels of terrorism activity or terrorist attacks Unusual or irregular instrumentation readings or visual observations Alarms from automatic monitoring devices The O&M manual should indicate when an extraordinary inspection should occur. In some cases, the EAP may require activation. If an abnormal situation that is beyond the ability of the dam operator to evaluate is discovered, a qualified engineer must be consulted for additional expertise. Records of extraordinary inspections must be developed and filed. In certain cases, an incident report must be submitted to Dam Safety. See Chapter 11 for guidance on incident reporting. 10.4 Periodic Safety Inspections The PSI is another form of communication that is extremely important during the operational stage in the regulatory life of the dam. PSIs are mandated by 11 AAC 93.159 for all dams under the jurisdiction of the ADSP. The regulations require Dam Safety to provide written guidelines for the inspection and to approve the PSI report. In addition, the inspection must be conducted by an engineer approved by Dam Safety who meets the qualifications under 11 AAC 93.193(b). The PSI for all dams under state jurisdiction should he conducted in accordance with the guidelines contained in this section. The PSI is required at the following intervals based on the hazard potential classification: Class Interval I and II Three years 111 Five years To facilitate approval and foster communication, the following review process is suggested: The qualifications of the engineer should be submitted for review and approval by Dam Safety before the inspection is conducted. The engineer must meet the appropriate requirements, as described in Subsection 1,3.4. If different from the approved scope of work outlined in Subsection 10.4,2, the scope of the PSI should be pre-approved by Dam Safety. Two draft copies of the PSI report should be provided within 30 days of the field inspection for review by Dam Safety. Dam Safety will review the draft and return a copy to the engineer with common ts in redline on the pages of the report. The engineer will review the comments from Dam Safety and revise the draft to appropriately address any outstanding concerns. At least two final versions of the PSI report with the engineer's seal and signature should then be submitted to Dam Safety. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 10-3 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 106 of 230 ED 002061 00172725-00106 Ci to Table of Contents C hapter 10. Inspections Dam Safety will approve the final version of the report, assuming any comments or concerns indicated on the draft version are satisfactorily addressed. One copy of the report will be retained for Dam Safety records and any additional copies will be returned to the engineer with an approval signature from the State Dam Safety Engineer. Figure 4-3 illustrates the typical inspection and review process for the PSI of dams under the jurisdiction of the ADSP. The following subsections provide guidance on conducting the PSI, outline an approved scope of the PSI, and suggest the format of the PSI report, regardless of the hazard potential classification assigned to the dam. 10.4.1 Guidance on Conducting the PSI This subsection provides guidance on conducting the PSI. The PSI is intended to be a comprehensive review of the dam and appurtenances with the specific intent of determining potential problems that could lead to malfunction or failure of the dam. The unique aspects of the dam that could lead to a failure should be identified, as well as the parameters that should be investigated or monitored to determine the current and future performance of that aspect of the darn. These performance parameters may require special attention or focus during the review process. Identifying and reporting on the performance parameters of the dam is one of the primary functions of the engineer during the PSI. See Performance Parameters for Darn Safety Monitoring in Appendix F for more information (USER, 1995), The PSI should identify and review the potential problems and performance parameters from the following perspectives: Building the Base of information The PSI adds to the base o f the previous information known about the dam. If the design and construction were not properly developed and documented, the first PSi and subsequent studies m ay be quite involved. As the performance parameters are understood, the subsequent PSis m ay be less extensive. Subsequent PSIs may Historical - The PSI should look back to build on the information contained determine whether the design and in previous PSi reports, assuming construction of the dam appropriately that those previous reports are addressed specific concerns associated with reviewed with the same objectives as the performance parameters. For example, if the stability of the upstream slope of an any historical information is reviewed. embankment dam is a concern, a number of questions may arise: Was a slope stability analysis conducted in the design or subsequently? is the analysis still valid? Was the analysis comprehensive and include alternative scenarios such as rapid draw down conditions? Were the input values assumed or were laboratory tests results from site-specific ma terials used? G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 10-4 Tier 10 Revision 1 June 30, 2005 Attachment F Page 107 of 230 ED 002061 00172725-00107 Go to Table of Contents C hapter 0. Inspections Are those values appropriate? Is the safety of the darn sensitive to those parameters? Are additional investigations, tests, and analyses required? In another example, if seepage is a potential problem, these questions may arise: Is seepage cloudy or clear? Do observations or monitoring data show an increase in flow rate? Are the frequencies and methods of monitoring adequate? Were blanket drains included in the design and construction records? Were filters installed? Do fill materials meet gradation criteria for filters? The historical portion of the PSI should include a review of records such as design reports, construction reports, record drawings, previous PSI reports, photographs, routine visual inspection checklists, and monitoring data, Remedial Investigations and Repairs To limit the scope of the PSI for economic reasons, remedial investigations that the PS! identifies as being necessary to further understand a potential problem may be listed as a recommendation in the PSi report. For situations that are not urgent, Dam Safety encourages a thorough understanding of the potential problem and the best solution, before construction dollars are spent trying to mitigate the problem. The subsequent Certificate o f Approval to Operate a Dam will list the remedial investigation as a condition to be completed within the timeframe agreed upon, if a situation is determined to be urgent, and the dam owner or operator does not take immediate steps to resolve the problem, Dam Safety may be compelled to issue an order in accordance with 17 A A C 93. i 59(d). See Section 72 for additional information. Current - The PSI should observe and report on current conditions at the dam, including all performance parameters previously and currently identified, as well as other aspects that may be subtle or apparent. The current portions of the PSI will include the following: Visually inspecting and photographing the dam and its appurtenant structures and facilities Observing operational procedures such as opening and closing gate valves or testing alarms Reading instrumentation such as piezometers or surveying monuments The current portion of the PSI should include comparing the current observations to the historical observations for change. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 10-5 Tier 10 Revision 1 June 30, 2005 Attachment F Page 108 of 230 ED 002061 00172725-00108 Ci to Table of Contents C h a p t e r 1 0. In s p e c t io n s Future - The PSI should process and evaluate the information that is collected and anticipate the behavior of the performance parameters under anticipated and unanticipated future conditions. Examples are provided below: If the comparison of current to historical information indicates a deteriorating condition, will the performance of the system be jeopardized during normal or extreme operating conditions? If the expected performance is not acceptable or uncertain, is a remedial investigation, repair or modification required? The PSI should include specific conclusions about the status and safety of the dam and include recommendations for any additional work that may be required. 10.4.2 Scope of the PSI The following is a generic scope of a typical PSI that is approved by Dam Safety: Complete the Hazard Classification and Jurisdictional Review Form. (See Section 2,4.) Describe the potential impacts of a dam failure on the community, and if required, the suggested scope of an EAP if one is not available. Review any available historical information such as: Previous PSI reports Hydrological and stability evaluations Design and construction reports Certificates of approval for dam construction, operation, or both Determine if the design is contemporary, design assumptions are valid, and construction occurred according to the design Determine whether compliance occurred for previous recommendations for maintenance, inspections, or repairs Review routine inspection records, monitoring data, and surveys; provide discussion, summary tables, and charts of any data analysis; and include raw data in appendices, as appropriate Visually Inspecting a Dam To properly conduct a visual inspection as part of a PSi, the dam must he visible. Consequently, the visual inspection must be conducted when the dam is clear of snow, excessive brush, and tall grass that m ay impede the inspection. In addition, all operational and emergency controls on the dam should be exercised during the PSI, so that the inspector can see whether the controls are operating properly. Visually inspect the dam, reservoir, spillways, outlet works, and other appurtenant structures and complete the appropriate sections of the ADSP Visual Inspection Checklist (included in Appendix G and available from Dam Safety as an Excel spreadsheet upon request). Any anomalies should be noted on the checklist and discussed in the PSI report. G u id e l in e s f o r C o o p e r a t io n w it h the A laska D a m Safety Pro g ram Sierra Club v. EPA 18cv3472 NDCA 1 0 -6 Tier 10 R ev isio n 1 June 30, 2 0 0 5 Attachment F Page 109 of 230 ED 002061 00172725-00109 Ci to Table of Contents C h a p t e r 1 0. In s p e c t io n s Collect and include key photographs in the PSI report with identifying captions Review the O&M manual for currency and relevancy to the darn, including any and all available records for compliance with routine and special monitoring or maintenance requirements of the manual Review the project data sheet, confirm the information listed therein, and include in the appendices if updated. Describe and discuss key elements of the dam, appurtenant structures, foundation, abutments, reservoir rim, and other features that are critical to the safe performance of the dam List and discuss the critical performance parameters associated with the darn, including hydrology and hydraulics, geology and geotechnical considerations, seepage, static and seismic stability, and other performance parameters such as deferred maintenance or deterioration List specific conclusions about the condition and safety status of the dam, pertinent observations, and professional opinions, with appropriate references to methodologies, calculations, publications, textbooks, or other information used to justify any opinions List specific recommendations for additional studies, analyses, inspections, monitoring, maintenance, or repairs, if required for any potential problems that are identified Certify the PSI report with the signature and seal of the engineer conducting the inspection 10.4.3 Format of PSI Report The following general format is requested for PSI reports: Title Page Dam name and NID number Certification, and Approval Sheet Engineer's seal and signature and the date Lines for the ADNR approval signature and date 1. Introduction Location and ownership Reference to approved scope of the inspection Project description Hazard potential classification review 2. History General background Construction history Design history Inspection history Dam Safety Inspection Training The US. Bureau of Reclamation presents the Safety Evaluation of Existing Dam s (SEED) seminar annually in Denver, Colorado. This excellent seminar is an intensive oneweek training opportunity that is highly recommended for engineers, dam owners, and dam operators. Contact the USER at (303) 445-2740 for more information. G u id e l in e s f o r C o o p e r a t io n w it h the A laska D a m Safety Pro g ram Sierra Club v. EPA 18cv3472 NDCA 1 0 -7 Tier 10 R ev isio n 1 June 30, 2 0 0 5 Attachment F Page 110 of 230 ED 002061 00172725-00110 Go to Table of Contents C h a p t e r 1 0. In s p e c t io n s 3. Current Field Inspection Date and inspection personal Description of environmental conditions during tire inspection Highlights of visual inspection, including unusual conditions or problems 4. Operations and Maintenance Review 5. Monitoring Data Review 6. Discussion of Key Elements of the Dam and Appurtenances 7. Review of Performance Parameters 8. Conclusions on the Safety of the Dam and Future Performance 9. Recommendations for Additional Work Appendices A. Hazard Classification and Jurisdictional Review form B. Photographs C. Visual Inspection Checklist D. Project Data Sheet (if updated) E. Other appendices as needed, such as technical evaluations or monitoring data 10.5 ADNR Field Inspections The State Dam Safety Engineer or other members of the DNR may conduct a field inspection in accordance with AS 46.17.060 and 11 AAC 93.161 or 11 AAC 93.173(c)(3). A field inspection is defined herein as a limited inspection conducted onsite by the ADNR before, during, or after construction. Field inspections may also occur during routine operation or emergency conditions at the dam. Field inspections may include the dam and reservoir, appurtenant works such as spillways and penstocks, detailed construction activity, and records. Assuming a cooperative relationship exists between Dam Safety and the dam owner or operator, written notice of the inspection will not occur as indicated in the statutes and regulations if the visit is prearranged. G u id e l in e s f o r C o o p e r a t io n w it h the A laska D a m Safety Pro g ram Sierra Club v. EPA 18cv3472 NDCA 1 0 -8 Tier 10 R e v isio n 1 June 30, 2 0 0 5 Attachment F Page 111 of 230 ED 002061 00172725-00111 Go to Table of Contents Guidelines for Cooperation with the A laska Dam Safety Program Chapter 11 PERFORMANCE AND INCIDENT REPORTING 11.1 Reporting Guidelines........................................................................................................11-2 11.2 Reporting Requirements...................................................................................................11-2 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 112 of 230 ED 002061 00172725-00112 Go to Table of Contents Chapter 11 PERFORMANCE AND INCIDENT REPORTING In this chapter: > Purpose and description o f dam performance and incident reporting > Guidelines for reporting dam incidents > Description o f incidents fo r which reporting is required Regulations under 11 AAC 93.177 require the reporting of certain incidents at darns to Darn Safety. Collecting information about the performance of dams is important for understanding the condition of dams in Alaska and to evaluate the effectiveness of design and inspection standards. In addition, performance and incident reporting allows Dam Safety to participate with and contribute to the NPDP at Stanford University in California. Finally, performance and incident reporting provides assurance that dam owners and operators are inspecting dams during and after extraordinary circumstances. Reporting guidelines in this section are generally based on the Guidelines for Reporting the Performance o f Dams (NPDP, 1994). Those guidelines define an incident as follows: Events (e.g. load/'performance scenarios, dam operations during extreme or emergency conditions) which are of engineering interest due to the insights they provide on operational and structural performance of dams and public safety. This definition includes cases involving failure (i.e. breach and uncontrolled release of the reservoir), as well as a broader scope of events. The regulations paraphrase these guidelines and provide the following definitions of an incident: (1) the satisfactory or unsatisfactory performance of a dam during extreme loading periods caused by extraordinary seismic or hydrologic events; (2) the uncontrolled release of water from a dam due to improper operation, overtopping, excessive seepage, or piping, regardless of whether downstream flooding occurs; (3) indications of stress in structural features or appurtenant works that could potentially affect the structural or operational integrity of the dam; (4) severe deterioration or erosion of structural elements or materials of construction, including concrete, steel, timber, soil, rock, geosynthetics, pipes, and valves; G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 1 M Tier 10 Revision 1 June 3 0,2005 Attachment F Page 113 of 230 ED 002061 00172725-00113 Go to Table of Contents C h a p t e r 1 1, P e r f o r m a n c e a n d In c id e n t R e p o r t in g (5) modifications or repairs to the dam required to satisfy regulatory requirements or other deficiencies that may be identified in the darn or the original design basis. Table H-l in Appendix H-l provides additional detailed guidance from the Guidelines for Reporting the Performance of Dams (NPDP, 1994) to determine whether an incident has occurred. 11.1 Reporting Guidelines If an incident occurs, the dam incident notification (DIN) form presented in Appendix H-2 should be completed and submitted to Dam Safety along with a dam incident documentation report (DIDR) that includes the following information: A chronology of events before, during, and after the incident A description of the satisfactory or unsatisfactory performance of the dam, reservoir, and related appurtenances during the incident, including photographs and a detailed description of any damage caused by the inciden t to the dam or appurtenances A description of the effects of the incident on downstream interests Actions taken by the dam owner, dam operator, or emergency response agencies during and after the incident Activities following the incident, including a description of repairs, or plans for future work or operating changes resulting from the incident Estimate of the economic and social impacts of the incident to the dam owner and other affected interests 11.2 Reporting Requirements Incident reporting is mandatory for all dams. Table 11-1 recommends minimum reporting requirements based on the hazard potential classification and the na ture of the incident. Reports should be submitted to Dam Safety within 30 days of the incident. Table 11-1. Reporting of Dam Incidents Based on Hazard Potential Classification Incident Type Hazard P otential C lassificatio n I II III Seismic X X X Hydroiogic X X X Failure or breach X X X Deterioration X X Mis-operation X X EAR activation X G u id e l in e s f o r C o o p e r a t io n w it h th e A laska D a m Safety Pr o g r a m Sierra Club v. EPA 18cv3472 NDCA 1 -2 Tier 10 R e v isio n June 30, 2 0 0 5 Attachment F Page 114 of 230 ED 002061 00172725-00114 Go to Table of Contents C hapter 1 1, Performance a n d Incident Reporting Hydrologic incident reporting shall be conducted in accordance with the guidance presented in Appendix H-3. Seismic incident reporting shall be conducted in accordance with the guidance presented in Appendix H-4. Dam Safety may request incident reporting for any classification dam for any incident. Additional reporting guidance will be provided at the time of the request. A complete copy of the NPDP Guidelines for Reporting the Performance o f Dams (1994) can be obtained from the NPDP at Stanford University. Information is available through the following Web address: http:/,/npdp.stanford.edu/index.html. All incident reports will be forwarded to the NPDP, unless written justification for confidentiality is submitted by the dam owner. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 11-3 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 115 of 230 ED 002061 00172725-00115 Go to Table of Contents j C hapter 1 1, Performance a n d Incident Reporting G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 1 1-4 Tier 10 Revision 1 June 3 0 ,2005 Attachment F Page 116 of 230 ED 002061 00172725-00116 Go to Table of Contents Guidelines for Cooperation with the --- A la sk a Dam Safety P ro gra m Chapter 12 REMEDIAL INVESTIGATIONS AND DECISION MAKING 12.1 Remedial Investigations and Repairs.............................................................................. 12-1 12.2 Emergency Actions.......... ................................................................................................. 12-2 12.3 Techniques for Making Decisions....................................................................................12-3 12.3.1 Risk Management......... ...................................................................................... 12-3 12.3.2 Decision Matrices..................................................................................................... 12-4 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 117 of 230 ED 002061 00172725-00117 Go to Table of Contents Chapter 12 REMEDIAL INVESTIGATIONS AND DECISION MAKING In this chapter: > Discussion o f remedial investigations and repairs > Outline o f priorities when making decisions under emergency situations > Review o f decision-m aking techniques tha t are useful fo r dam safety purposes A variety of circumstances associated with dams may warrant special considera tion in deciding about the proper course of action. From choosing an appropriate location for a dam, to remedial construction on a deteriorated dam, to breaching a dam under emergency conditions, decisions about dams can be expensive, complex, and even a matter of life and death. The purpose of this section is to outline methodologies for making decisions that may be required to meet the intent of the dam safety regulations or that may be otherwise useful in making important decisions about dams. 12.1 Remedial Investigations and Repairs Routine inspections, PSIs, or special engineering evaluations may indicate that certain repairs are necessary to reduce the probability for failure for the long-term safety of the dam. However, the repairs may not be required immediately. For example, the dam may not be in immedia te danger of failing, but may not withstand certain loads imposed by some probability-based event such as heavy precipitation or earthquakes. In this case, remedial investigations may be prudent to determine the magnitude of the problem, the optimum solu tion, or both. Rather than proceed with a costly construction project, the dam owner may prefer to conduct additional monitoring or evaluations. In some cases, a remedial investigation may be ordered by Dam Safety under the authority of AS 46.17.070,11 AAC 93.159(d), 11 AAC 93.161, or 11 AAC 93.163. The hazard potential classifica tion and the apparent condition of the dam are the primary factors in determining the level of urgency for non-emergency repairs. Dam Safety will consider arguments presented by the dam owner to defer construction costs; however, additional studies, such as more detailed engineering evaluations and limited risk assessments, or mitigating measures, such as EAR development and exercises, may be required in the interim. Generally speaking, Dam Safety encourages a thorough understanding of the problem before construction dollars are spent in an attempt to remediate the dam. Guidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 12-1 Tier 10 Revision 1 June 30, 2005 Attachment F Page 118 of 230 ED 002061 00172725-00118 Go to Table of Contents C hapter 1 2, Remedial Investigations a n d D ecision M aking In any event the following requirements should be considered before remedial investigations and repairs of darns begin: All repairs should be reviewed with Dam Safety to determine if a Certificate ofApproval to Repair a Dam is required. Intrusive investigations should be reviewed with Dam Safety before they are initiated. The location and potential effects of the reservoir level and phreatic surface in the dam must be evaluated before intrusive investigations or repairs. Test pits conducted on dams must be backfilled with compacted soil similar to in situ conditions. Boreholes in dams must be backfilled with cement grout. Colla teral effects of the proposed repair must be considered in the evaluation. For example, if a leaking, corrugated metal, low-level outlet pipe is slip-lined and grouted, the seepage through the embankment may be adversely affected. In other words, care must be given to the level of intervention necessary to avoid harming the patient (the dam) during the diagnosis and treatment of the illness. Remedial investigations should be conducted in accordance with guidance provided in the most current version of the following reference: Safety Revaluation of Existing Darns by the USER (1995) 12.2 Emergency Actions As discussed in Chapter 9, Dam Safety is requiring the development of EAPs for Class I and II dams and encouraging the inclusion of unusual occurrence procedures in O&M manuals for all dams regulated under the ADSP. These documents should provide predetermined responses to certain situa tions that will reduce the decision-making burden at the time of the emergency. Recognizing that real-life situations are almost always different than theoretical simulations, emergency decisions may require a different approach from those anticipated. The primary motivation for any decision made under emergency conditions is to protect life and property. The following information, in a descending order of priority, should be considered wrhen making emergency decisions: Does the decision protect life and property from an impending failure of the dam or uncontrolled release of water? Can actions occur that will prevent a failure of the dam withou t diverting resources that are required to protect life and property? Can any actions be taken to relieve any stress on the dam in a controlled manner that will reduce or eliminate the threat of failure? Can the reservoir be lowered or the dam breached in a control led manner that does not result in the same consequences as if the dam were to have failed anyway? Guidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 12-2 Tier 10 Re v isio n ! June 30, 2005 Attachment F Page 119 of 230 ED 002061 00172725-00119 Go to Table of Contents C hapter 12, Remedial Investigations a n d D ecision M aking In all cases, Dam Safety reserves the authority given to the ADNR under 11 AAC 93.163 to take the remedial action necessary to mitigate the risks posed by the operation or failure of the dam until the emergency passes. Such emergency action may include breaching the dam intentionally or other construction-related activity. If the owner refuses to conduct the work ordered by Dam Safety under emergency conditions, Dam Safety may retain contractors, consultants, or other entities to conduct the work, in wrhich case the owner will be liable for the incurred costs. Except as identified in AS 47.17.110, a person may not bring an action against the state, the ADNR, or its agents or employees for "measures taken to protect against tire failure of a dam or reservoir during an emergency." For purposes of clarification, a controlled breach of the dam is not considered to be a "failure of a dam or reservoir," but may be the only practicable solution to prevent the failure of the dam or reservoir under certain conditions. 12.3 Techniques for Making Decisions 12.3.1 Risk Management Generally speaking, the ADSP uses a standards-based approach to manage the risks posed by dams, rather than a formal risk management program that includes risk assessment, risk analysis, and risk evaluation. A detailed discussion of these topics is outside the scope of these guidelines. However, dam safety management is intrinsically risk based, because the standards are keyed to the hazard potential classification, which is assigned based on the relative risk that the dam represents. The challenge is that the actual risks are not always quantified and, therefore, may be poorly understood by the various parties responsible for making important decisions about the dam. One primary purpose of the PSI is to identify deficiencies that indicate an increase in the risk created by the dam; however, the costs to address those deficiencies with the use of a standards-based approach may be extremely high, and the benefits, or reduction in risk, may not be readily apparent. In this case, a formal risk assessment may be used to accomplish the following: Gain a more clear understanding of the risks posed by the dam and its related deficiencies Set priorities for the mitigation efforts necessary to reduce the risk Compare the risk reductions of construction versus non-construction options Determine if operating restrictions or decommissioning may be more practical than remedia 1construction Failure Mode and E ffects Analysis A risk assessment focused on a dam m ay take the form of a failure mode and effects analysis (FMEA). The FMEA is a detailed look at all possible ways in which the dam may fail and the potential effects of each type of failure from a broad perspective. For each failure mode, the likelihood of occurrence is assigned. The probability of failure combined with the potential consequences allows decisions on utilizing resources to be made with higher levels of confidence. For more information about the FMEA, see the Association of State Dam Safety Officials (1999) or Robertson (2003) references in Chapter 14. Guidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 12-3 Tier 10 Re v isio n ! June 30, 2005 Attachment F Page 120 of 230 ED 002061 00172725-00120 Go to Table of Contents C hapter 12, Remedial Investigations a n d D ecision Making The risk assessment may also be used to understand and quantify the risks created by a dam, even though no deficiencies are apparent. Formal risk assessments are complex and expensive, bu t may yield useful and justifiable results when properly conducted. Dam Safety will consider a risk assessment submitted by a dam owner if it is appropriately conducted by a team that includes a qualified engineer familiar with the dam and a qualified and experienced risk assessment consultant. Additional informa tion about risk assessment as a tool for managing dam safety is included in a technical paper (Bowles et al., 1997) presented in Appendix J. Dam Safety agrees with the following conclusion by the authors: The true nature of dam safety management is intrinsically a problem in risk management and decision making under uncertainty... The risk management approach should treat dams as integral structures whose safety should be managed in a holistic manner... Adopting a "decision driven" approach to risk assessment will provide a basis for appropriate and justifiable limits on the level and detail of risk assessment efforts with the goal of reaching a quality, well communicated and highly defensible dam safety decision... When properlyimplemented, risk assessmen t can serve as a valuable tool within a comprehensive risk management framework for effective dam safety management. We further suggest that such a comprehensive and systematic approach is necessary for the proper exercise of duty of care of a dam owner and to assist in meeting due diligence [sic], 12.3.2 Decision Matrices Decision matrices can be simple, useful devices for making decisions without the expense of comprehensive risk assessments. Decision matrices are encouraged in feasibility and siting studies because of the clarity they provide in outlining and evaluating multiple criteria that can influence the decision. Decision matrices contribute to a systematic and clearly communicated approach for selection of a preferred alternative. In developing a decision matrix, the following guidelines should be considered: The criteria to be evaluated should be comprehensive, logically organized, and clearly presented. The rating values should be simplistic and match the level of detail available; for example, rating values of 1, 2, or 3 are better than 1 through 10 if sufficient information is not available for all of the criteria to assign a finer rating system. Rating assignments should be listed for each criterion. Weighted and unweighted summations, as appropriate, should be included. Weighting assignments should be simplified and clearly explained. An exam ple of a sim ple decision matri x is presented in A ppendix j. Guidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 12-4 Tier 10 Revision 1 June 30, 200 5 Attachment F Page 121 of 230 ED 002061 00172725-00121 Go to I'able of Contents Guidelines for Cooperation with the A laska Dam Safety Program Chapter 13 CLOSURE 13.1 Removal................................................................................................................................13-1 13.2 Abandonment........... .................................................................................................. 13-2 13.2.1 Water Dams............................................................................................................... 13-2 13.2.2 Tailings Storage Facilities....................................................................................... 13-2 1 3 .3 O th e r I s s u e s .............................................................................................................................................................. 1 3 -5 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 122 of 230 ED 002061 00172725-00122 Go to Table of Contents Chapter 13 CLOSURE In this chapter: > Guidelines for the removal or abandonm ent of dam s > Considerations for the closure of tailings dams, from design to closure > Review of other issues associated with dam removal and current references When the life of a dam approaches the end of its usefulness, safety must be a primary factor when closure of the facility is planned. Therefore, an application for a certificate of approval is required under 11 AAC 93.172 to remove or abandon a darn. All applications should include the following information: An application fee based on the cost of the engineering, construction or demolition, and erosion control calculated in accordance with Section 3.4 Design drawings and specifications for the final configuration of the dam and reservoir site For Class I and II dams, seal and signature of a qualified engineer on the drawings and specifications Method and means to dewater or stabilize the reservoir and breach, remove, or abandon the dam For any case, the following submittals must be submitted to Dam Safety within 30 days after the closure work is completed: Description of how removal or abandonment activities were conducted Description of unexpected conditions encountered Photographs documenting construction or demolition progress and final conditions Additional information about removal and abandonment follows, including a discussion on the abandonment of darns at mine tailings storage facilities and references on dam removal. 13.1 Removal Removal of the complete dam structure is the preferred alternative for closure of a jurisdictional dam; however, removal of the entire structure may be cost prohibitive in some cases. The following are important requirements for the partial or complete removal of a dam: The dam must be breached to the point that the dam no longer impounds a reservoir. G uidelines for C ooperation w it h the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 1 3-1 Tier 10 Revision 1 June 3 0,2005 Attachment F Page 123 of 230 ED 002061 00172725-00123 Go to Table of Contents C hapter 1 3, C losure The breach must be sufficient to pass a design storm event such as the PMF without restricting the flow and backing up wrater. The breach must not be susceptible to clogging from sedimentation or woody debris. The sides of the breach must be stable over the long term. Erosion in the area of the breach must be controlled. Erosion from sediments in the reservoir must be evaluated and controlled if necessary. An application for a Certificate o f Approval to Remove a Dam must be submitted to Dam Safety. A copy of the application form is available upon request. The following additional information should be included with the applica tion: Method and means to control erosion at the site during and after breaching or removing the dam, including these specific details: Control of sediment transport from tire reservoir area Restoration of the reservoir bed and stream channel or other reclamation if the entire structure is not removed, these additional specific elements: Hydrologic and hydraulic evaluation of the proposed final configuration of the dam or barrier during the probable maximum flood or other 1FD Stability valua tion of the proposed final configuration of the dam or barrier under static and dynamic (seismic) conditions O&M requirements for the proposed final configuration of the dam or barrier Statement about whether the final configuration of the dam or barrier constitutes a dam as defined under AS 46.17.900 and remains under jurisdiction of the Alaska dam safety regulations 13.2 Abandonment In some cases, a dam may be abandoned without removing the dam. The dam may either be removed from state dam safety jurisdiction or remain under state jurisdiction indefinitely. These alterna tives are discouraged for water dams; however, a mine tailings dam is a special situation for wrhich abandonment is the ultimate fate of the darn from the beginning. The circumstances for which abandonment may be acceptable are discussed in the following subsections. 13.2.1 Water Dams Abandonment may be approved for a water dam if the reservoir is full of sediment, there is no opportunity for impoundment to occur, and other safety considerations are evaluated such as stability of the system and public safety. In this case, the sediment must be naturally occurring, such as bed load in an aggrading stream. Under no circumstances will the abandonment of a dam be approved based solely on opening the low level outlets and draining the reservoir. Any Guidelines for C ooperation with the A laska Dam Safety Program Sierra Club v. EPA 18cv3472 NDCA 13-2 Tier 10 Revision 1 June 30, 2005 Attachment F Page 124 of 230 ED 002061 00172725-00124 Go to Table of Contents C hapter 1 3, C losure abandonment of a dam approved by Dam Safety in no way relieves the dam owner of any other obligations that may be required under other statutes and regulations. 13.2.2 Tailings Storage Facilities Dams at tailings storage facilities are unique because the service life of the dam is infinite, generally speaking. When the reservoir is full of tailings and the facility is closed, the dam must remain in place and continue to retain the substance for an indefinite period of time while withstanding the effects of surface runoff and groundwater as the system is transformed from an active, operational condition to an inactive, closed condition. The closure of a tailings dam is typically included in a mine reclama tion plan; however, the engineering details in reclamation plans are usually limited because of the difficulty of planning for a long period in advance. Consequently, it is imperative that the initial design and construction address the detail necessary to ensure the long-term safety of the structure after closure. Furthermore, mining operations must also occur in a manner to facilitate closure. Nevertheless, such preplanning must retain a certain degree of flexibility to accommodate changes in the economic, social, and regulatory setting at the time of closure. The additional detail necessary for closure must therefore be provided in an application for a Certificate of Approval to Abandon a Dam submitted to Dam Safety. The guidelines presented in Chapter 4 and 5 are recommended for this application also. Complete guidance on tailings dam design and closure is beyond the scope of this document. Although many design principles of tailings dams are consistent with those for water darns, tailings darns represent certain challenges that require professionals with significant relevant experience. A failure rate for tailings dams that is statistically higher than for water dams is addressed in the following excerpt from "Tailings Dam Failures - the Human Factor" by Alan H. Gipson (2003): When compared to water darns the current failure rate of tailings facilities is unacceptable. In my view the primary reason for the failure rate is that owners, engineers, designers and operators are not performing their work in accordance with the standards of practice that should be followed. Utilizing knowledgeable experienced professionals for policy setting, planning, design, construction and operation of tailing facilities with appropriate internal peer reviews and regulatory oversight by trained and experienced professionals with appropriate levels of funding can lead to the goal of zero failures, [sic] To promote development of safe and effective tailings dams, Dam Safety offers the following regulatory perspective on tailings dam design and closure. G uidelines f o r C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 13-3 Tier 10 Revisio n ! June 30, 200 5 Attachment F Page 125 of 230 ED 002061 00172725-00125 Ci to Table of Contents C hapter 1 3, C losure Initial Design and Construction See Chapters 6 and 7 for general design and construction guidance that is applicable to tailings dams. The following closure concerns should be addressed in the initial design and construction of a tailings dam: The phreatic surface within the dam and tailings during operation and closure The amount and effects of tailings consolidation during operation and closure The internal drainage system of the dam, such as chimney drains, blanket drains, and toe drains to control seepage throughou t operation and closure The conceptual, final configuration of the dam and tailings impoundment with respect to land forms, erosion, pollution control, residual ponds, and surface water runoff Dam safety regulations that may remain in effect because of the configuration of the remaining impoundment, including both the residual pond and the tailings Closure Design The following closure concerns should be addressed in a detailed design before closure: Potential failure modes of the dam and tailings storage system in the final configuration, possibly including a risk assessment Hydrology and hydraulic aspects necessary to determine and accommodate an IDF equal to the PMF or some other extreme storm event Current data on the chemical and geotechnical nature of the tailings Precedent for Tailings Dam Closure The precedent for dosing tailings dam s in Alaska is extremely limited, although a number of important projects in the state will have to address this problem in the near future. Dam Safety is interested in the precedent for this activity in other areas, both in practice and in regulatory requirements. For example, the Web site for the Nevada Division of Water Resources (h ttp ://w a te r.n v .g o v /E n g in e e rin g / dam safety.htm l indicates that when a tailings facility is closed, "the mining company is responsible for breaching the dam or otherwise rendering the dam incapable of impounding any mobile material" (emphasis added). The Washington Administrative Code (WAC) provides for the regulation of any dam that contains more than 10 acre-feet "which contains any substance in combination with sufficient water to exist in a liquid or slurry state at the time of initial containment" (Chapter 173-175, WAC Dam Safety, October 24, 1995); however, the code is silent on the closure of a dam containing such substances. Long-term expectations for consolidation of the dam and tailings, the phreatic surface within the dam and tailings, the performance of the dam underdrain, and the quantity and characteristics of seepage G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 13-4 Tier 10 Revision 1 June 30, 2005 Attachment F Page 126 of 230 ED 002061 00172725-00126 Go to Table of Contents C hapter 1 3. C losure Stability of the system under static and seismic conditions, by using appropriate seismic parameters for a long-term condition Grading and soil stabilization, including contour maps and cross sections of the final configuration O&M requirements for the dam and reservoir in a closed condition, including regulatory requirements if the closed configuration represents a dam and reservoir as defined in AS 46.17.900 Bonding An appropriate bond or other form of financial assurance may be required to cover the O&M costs, regulatory inspections, and other expenses after the facility is closed. A written agreement that outlines the management of the financial instrument during the life of the project and after closure when the funds are utilized, including long-term responsibilities, must also be established. See Subsection 5.2.2 for more information. 13.3 Other Issues Other issues that are important to the closure of dams include the following: Funding the removal or abandonment River restoration and fisheries Social and economic impacts These issues are important and contemporary, but beyond the scope of this document to address. However, the following recent publications may be useful: Dam Removal: A New Optionfor a New Century, published by the Aspen Institute (2002) Payingfor Dam Removal: ,4 Guide to Selected Funding Sources by Betsy Otto, published by American Rivers (2000) Dam Removal Success Stories: Restoring Rivers Through Selective Removal of Dams That Don't Make Sense, published by American Rivers, Friends of the Earth, and Trout Unlimited (1999) GUIDELINES FOR COOPERATION W IT H the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 13-5 Tier 10 REVISION 1 June 30, 2005 Attachment F Page 127 of 230 ED 002061 00172725-00127 Go to Table of Contents C hapter 1 3, C losure G uidelines for C o o pera tio n with the A laska D a m Safety Program Sierra Club v. EPA 18cv3472 NDCA 1 3-6 Tier 10 R evision 1 June 3 0 ,2 0 0 5 Attachment F Page 128 of 230 ED 002061 00172725-00128 Go to Table of Contents Guidelines for Cooperation with the Alaska Dam Safety Program Chapter 14 REFERENCES Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 129 of 230 ED 002061 00172725-00129 Go to Table of Contents Chapter 14 REFERENCES In this chapter: > References used in the development of this document > References fo r other useful resources related to dams Alaska Department of Fish and Game, Habitat Division. 1998. Catalog of Waters Important for Spawning, Rearing or Migration of Anadromous Fishes. Juneau, Alaska. American Rivers, Friends of the Earth, and Trout Unlimited. December 1999. Dam Removal Success Stories: Restoring Rivers Through Selective Removal o f Dams That Don't Make Sense. American Society of Civil Engineers, Hydraulics Division, Committee on Surface Water Hydrology, Task Committee on Spillway Design Flood Selection. 1988. Evaluation Procedures for Hydrologic Safety o f Dams. Aspen Institute, Program on Energy, the Environment, and the Economy. 2002. Dam Removal: A New Option for a New Century. Association of State Dam Safety Officials. January 1996. Environmental Permittingfor Dam Projects. Lexington, Kentucky. _____. October 1999. Risk Assessment Workshop. Association of State Dam Safety Officials Conference. St. Louis, Missouri. October 11-15,1999. _____. February 2003. Technical Seminar on Plans and Specifications Review and Construction Inspection. Salt Lake City, Utah. _____. Undated. Dam Ownership: Responsibility and Liability. Public information pamphlet. Lexington, Kentucky. Bowles, D.S., L.R. Anderson, and T.F. Glover. 1997. "A Role for Risk Assessment in Dam Safety Management." Proceedings of the 3rd International Conference HydroPower '97. Trondheim, Norway. June 30 - July 2,1997. Cedergren, Harry R. 1989. Seepage, Drainage, and Flow Nets. John Wiley & Sons, Inc. CEA Technologies. February 2003. Static Ice Loads on Hydroelectric Structures: Ice Load Design Guide. EA Project T002700-0206). Cobb, Charles F. 1999. Dam Safety in Alaska: A Look Back and a Look Ahead. Alaska Department of Natural Resources, Division of Mining, Lands, and Water, Dam Safety Section. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. E P A 18cv3472 N D C A 14-1 Tier 10 Revision 1 June 3 0,2005 Attachment F Page 130 of 230 ED 002061 00172725-00130 Ci to Table of Contents C hapter 4. References Dobry R., R. Ramos, and M.S. Power. 1999. Site Factors and Site Categories in Seismic Codes. Technical Report MCEER-99-0010. Indiana Department of Natural Resources, Division of Water. 2001. General Guidelines for New Dams and Improvements to Existing Dams in Indiana. Indianapolis, Indiana. Federal Emergency Management Agency. March 1998a. Model State Dam Safety Program. FEMA 316 _____, Interagency Committee on Dam Safety. October 1998b. Federal Guidelines for Dam Safety: Hazard Potential Classification System for Dams. ____ . October 1998c. Federal Guidelines for Dam. Safety: Emergency Action Planningfor Dam. Owners. ____ . October 1998d. Federal Guidelines for Dam Safety: Selecting and Accommodating Inflow Design Floodsfor Dams. Federal Energy Regulatory Commission. 1993. Engineering Guidelines. Chapter II, Selecting and Accommodating Inflow Design Floods for Dams, Appendix II-A, Dambreak Studies. ____ yOffice of Energy Projects, Division of Dam Safety and Inspections. October 2000. Emergency Action Plan Exercise Design Course. Presented at various locations, including Anchorage, Alaska, in 2000. Fread, D.L. June 1987. BREACH: An Erosion Modelfor Earthen Dam Failures. National Oceanic and Atmospheric Administration, Hydrologic Research Laboratory, _____. June 20,1988. DAMBRK: The NWS-Dam Break Flood Forecasting Model. National Weather Service, Office of Hydrology. Silver Spring, Maryland. _____. April 2004. Dam Breach and Flood Wave Modeling. DVD published by Interagency Committee on Dam Safety, the U.S. Bureau of Reclamation, and Federal Emergency Managemen t Agency. Gipson, Alan H. 2003. Tailings Dam Failures - The Human Factor. Proceedings of the. Tenth International Conference on Tailings and Mine Waste. Vail, Colorado. October 12 - 15, 2003. Colder Associates. May 1998. Technical Review of Secondary Containment System Technologyfor Alaska. Final report to State of Alaska, Department of Environmental Conservation, Division of Spill Prevention and Response. Golze, Alfred R. 1977. Handbook of Dam Engineering. Van Nostrand Reinhold Company. Idriss, I.M., and J.I. Sun. 1992. User's Manualfor SHAKE91. Center for Geotechnical Modeling, Department of Civil and Environmental Engineering, University of California, Davis, California. Idriss, I.M., J. Lysmer, R. Hwang, and H.B. Seed. 1973. QUAD4 - A Computer Program for Evaluating the Seismic Response o f Soil Structures by Variable Damping Finite Element Procedures. University of California, Berkeley, California. Report EERC 73-16. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 14-2 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 131 of 230 ED 002061 00172725-00131 Go to Table of Contents C hapter 14, References Jones, Stanley H., and Charles B, Fahl. 1994. Magnitude and Frequency of Floods in Alaska and Conterminous Basins of Canada. U.S. Geologica l Survey. Water Resources Investigation Report 934179. Prepared in cooperation with the State of Alaska, Department of Transportation and Public Facilities and Federal Highway Administration. Kramer, S.L. 1996. Geotechnical Earthquake Engineering. New Jersey: Prentice Hall. Lee, M.K.W., and W.D.L. Finn. 1978. DESRA-2, Dynamic Effective Stress Response Analysis of Soil Deposits with Energy Transmitting Boundary Including Assessment o f Liquefaction Potential. Department of Civil Engineering, University of British Columbia, Vancouver, Canada. Spoil Mechanics Series 36. Miller, John F. 1963. Probable Maximum Precipitation and Rainfall Frequency Data for Alaskafor Areas to 400 Square Miles, Durations to 24 Hours, and Return Periods from 1-100 Years. U.S. Weather Bureau, Hydrologic Services Division, Cooperative Studies Section. Technical Paper 47. Prepared for U.S. Department of Agriculture, Soil Conservation Service, Engineering Division. National Performance of Dams Program, Stanford University. August 1994. Guidelines for Reporting the Performance of Dams. <http://npdp.stanford.edu/index.html>. _____. 2000. "NPDP Dam Performance Failures & Safety Related Incidents." Hydrovision 2000 Conferen ce Proceedirigs. National Oceanic and Atmospheric Administration, National Weather Service, Hydrological Research Laboratory, Office of Hydrology. November 28,1998. NWS FLDWAV MODEL. Silver Spring, Maryland. Otto, Betsy. October 2000. Payingfor Dam Removal: A Guide to Selected Funding Sources. American Rivers. Plafker, G,, and H.C. Berg, Editors. 1994. The Geolog)" of Alaska. The Geology of North America. Volume G-l. The Geological Society of America. Robertson, Andy M. 2003. Risk Management for Major Geotechnical Structures on Mines. Conference Proceedings of Computer Applications in the Mineral Industry. Calgary, Alberta, Canada. September 8, 2003. <http://www.robertsongeoconsultants.com/papers/cami03risk.pdf>. Schwartz, Francis K., and John F. Miller, National Weather Service, Office of Hydrology, Hydrometeorological Branch. September 1983. Probable Maximum Precipitation and Snowmelt Criteriafor Southeast Alaska. U.S. Department of Commerce, National Oceanic and Atmospheric Administration, and U.S. Department of Army, Corps of Engineers. Hydrometeorological Report 54. Silver Spring, Maryland. Seed, R.B., K.O. Cetin, R.E.S. Moss, A.M. Kmmerer, J. Wu, J.M. Pestana and M.F. Riemer. 2001. Recent Advances in Soil Liquefaction Engineering and Seismic Site Response Evaluation. Proceedings of the Fourth International Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics and Symposium in Honor o f Professor W.D. Liam Finn. San Diego, California. U.S. Army Corps of Engineers. June 1,1993. Quality Management. ER 1110-1-12. G uidelines for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 4-3 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 132 of 230 ED 002061 00172725-00132 Go to Table of Contents C hapter 14. References _____. July 1995. Earthquake Design and Evaluationfor Civil Works Projects. ER 1110-2-1806. _____. March 31,1998. Engineering and Design - Runofffrom Snowmelt. Chapter 10. EM 1110-21406. _____. 1999. Safety Evaluation of Existing Dams Seminar. U.S. Burea u of Reclamation. 1987. Design o f Small Dams. _____. 1990. "Module: How to Organize an Operation and Maintenance Program." Training Aids for Dam Safety. Denver, Colorado: U.S. Government Printing Office. _____. 1995. Safety Evaluation o f Existing Dams. U.S. Committee on Large Dams, Committee on Earthquakes. 1999. Updated Guidelines for Selecting Seismic Parameters for Dam Projects. U.S. Society of Dams (formerly U.S. Committee on Large Dams). U.S. Department of Agriculture, Soil Conservation Service. 1979. Simplified Dam Breach Routing Procedure. Technical Release 66. _____. 1986. Urban Hydrologyfor Small Watersheds. Technical Release 55. U.S. Geological Survey. 2003. USGS National Seismic Hazard Mapping Project - Interactive Deaggregations, 1996. Web page: h ttp ://eqintl.cr.usgs.gov/eq/htjml/deaggint.shtml. Washington State Department of Ecology. July 1992. "Dam Break Inundation Analysis and Downstream Hazard Classification." Dam Safety Guidelines. Technical Note 1. Wesson, R.L., A.D. Frankel, C.S, Mueller, and S.C. Harmsen. 1999. Probabilistic Seismic Hazard Maps o f Alaska. U.S. Geological Survey Open-File Report 99-36. Youd, T.L., and I.M. Idriss. 1997. Proceedings of the NCEER Workshop on Evaluation o f Liquefaction Resistance of Soils. Technical Report NCEER-97-0022, G u i d e l i n e s for C ooperation with the A laska Da m Safety Program Sierra Club v. EPA 18cv3472 NDCA 14-4 Tier 10 Re v is io n ! June 30, 2005 Attachment F Page 133 of 230 ED 002061 00172725-00133 Go to Table of Contents Guidelines for Cooperation with the Alaska Dam Safety Program Appendix A Hazard Potential Classification and Jurisdictional Review Form Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 134 of 230 ED 002061 00172725-00134 Go to Table of Contents Alaska Dam Safety Program HAZARD POTENTIAL CLASSIFICATION AND JURISDICTION AL RE VIEW This form is used to review and indicate the hazard potential classification o f an artificial barrier in accordance with 11 AAC 93.157 and to determine if the banter is a dam under the jurisdiction o f the Alaska dam safety regulations, based on the definition articulated under Alaska Statute 46.17.900 (3), and summarized as follows: '"Dam'' includes an artificial barrier, and its appurtenant works, which may impound or divert water and which... has or will have an impounding capacity- at maximum water storage elevation o f 50 acre-feet and is at least 10 feet in height measured from the lowest point at either the upstream or downstr eam toe o f the dam to the crest o f the dam; or * is at least 20 feet in height measured from the lowest point at either the upstream or downstream toe of the dam to the crest o f the dam; or poses a threat to lives and property- as determined by the department after an inspection. In accordance with 11 AAC 93.151, an artificial barrier with a Class I or Class II designation is determined to meet the third definition o f a dam, regardless o f its geometry. Please complete items 1 through 21. Attach additional information as necessary. Thisform m ust he certified and stamped on page 3 by an Alaska-registeredprofessional engineer, qualified in accordance with 11 A A C 93.193. 1. Name o f barrier: _____________________________________________________________________________ National Inventory- o f Dams (NID) number:________________________ (Assigned by Department) Name o f stream: _________________________________________________________________ General location and region: __________________________________________________________ Legal location: Township_____Range _______ Section_______ Meridian_____________ Purpose and type o f barrier:______________________________________________________________ This barrier is: Existing Current hazard potential classification: 1 Proposed Under construction II III Not assigned 2. Owner: Address: _____________________________________________________ Contact name: __________________________________________________ Phone: ______________________________ 3. Is barrier federally owned, or regulated by the Federal Energy Regulatory Commission? Yes (stop here) No (complete form) Version 7, 3/2005 Sierra Club v. E P A 18cv3472 N D C A 1 of 4 Tier 10 Alaska Department of Natural Resources Attachment F Page 135 of 230 ED 002061 00172725-00135 Go to Table of Contents | ADSP Hazard Potential Classification and Jurisdictional Review NIP No. 4. Maximum crest height o f barrier: feet Measured from: Upstream toe Downstream toe Basis o f height: Conceptual design drawing As-built drawing Field measurement Qffstream toe Detailed design drawing NID data 5. Maximum impoundment volume: _______________________acre-feet Surface area o f reservoir at maximum storage: _______________________ acres Average depth o f reservoir above bottom o f barrier: feet (live storage) Basis o f volume estimate: Surface area multiplied by average depth Bathymetry NID data Other: 6, Downstream development: Type o f development (check all that apply): Homes School Community halls, churches, etc. industrial or commercial property Major highway Primary roads Secondary or rural roads Railroads Yes No Unknown Power or communication utilities Water or wastewater treatment facilities or lines Overnight campgrounds Public parks or trails Fish hatchery or processor Barrier owner's property' or facilities Other utilities: Other development: Basis o f observ ations: Date o f observ ations: Ground reconnaissance Aerial photo Aerial reconnaissance Other: 7. Proximity o f development to downstream channel (add maps or other information as necessary'): Distance downstream from barrier: ______________________________ Distance from stream bed: ______________________________ Relative elevation above streambed: _____________________________ 8. Is development in the inundation zone o f a flood from an uncontrolled release o f water from the barrier? Yes No Unknown 9. Was a dam break analysis conducted? Yes No Basis o f determining inundation zone: Simplified DAM BRK model DAMBRK model (Please attach calculations) NWS FLDW AV model HEC-1 model Other:_____________________ Maximum depth and velocity o f flow through development:__________________ 10. Is development at risk from improper operation or a "sunny day" failure? Yes No Unknown 11. Is development at risk from an incremental increase in the flood if the barrier fails under flood conditions? Yes No Unknown Flood condition evaluated: 100 year Vi PMF PMF Other_________________________ Version 7, 3/2005 Sierra Club v. E P A 18cv3472 N D C A 2 of 4 Tier 10 Alaska Department of Natural Resources Attachment F Page 136 of 230 ED 002061 00172725-00136 Go to 'Table of Contents f AD8P Hazard Polcnlial Classification and Jurisdictional Review NIP No. 12. Could an uncontrolled release cause other significant property damage or loss? Yes No Unknown D e sc rip tio n :________________________________________________________________________________ 13. Could an uncontrolled release effect public health? Yes No Unknown D e sc rip tio n :________________________________________________________________________________ 14. Is the reservoir created by the barrier the primary water supply for a community o f more than 500 residents? Yes No Unknown 15. Is a backup water supply available? Yes No Unknown 16. Is barrier located on waters important toanadromous fish? Yes No Unknown 17. Are anadromous fish waters at risk o f damage or loss if an uncontrolled release occurs? Yes No Unknown 18. Proposed hazard potential classification: Class I (High) Class II (Significant) Class III (Low) 19. Basis o f classification: Quantitative - Numerical dam break analysis conducted Qualitative - Limited engineering calculations Preliminary - No engineering calculations 20. Comments: 21. Certified by : ____________________________________ (Print name) Date: Company : Phone: _____________________ Engineer's Seal and Signature Notes: 1. This form must be certified and stamped by an Alaska-registered professional engineer qualified in accordance Math 11 AAC 93.193. 2. The information presented in this form may be overruled based on current data that reveals a higher level o f confidence in the quality o f information necessary to make the appropriate determinations. 3. Anadromous fish waters are determined in accordance with 11 AAC 195.010 (a). 4. Alaska dam safety regulations are articulated under 11 AAC 93.151 through 11 AC 93.291 (Article 3). Version 1 , 3/2005 Sierra Club v. EPA 18cv3472 NDCA 3 of 4 Tier 10 Alaska Department of Natural Resources Attachment F Page 137 of 230 ED 002061 00172725-00137 Go to I a ble of Conten ts | ADSP Hazard Potential Classification and Jurisdictional Review NIP No. FOR DEPARTMENT USE ONLY Jurisdictional Status o f Barrier: Dam under state jurisdiction Barrier is not a dam under state jurisdiction Reasons: Height Height and storage volume Hazard potential classification Anadromous fish stream Other: Reasons: Height Height and storage volume Hazard potential classification Federal ownership or regulation Other: Concur with proposed hazard potential classification: Yes No Hazard potential classification based on current information: Yes No Official hazard potential classification: Class I (High) Class II (Significant) Class III (Low) Comments: Reviewed by: Title: Signature: Date: Version 7, 3/2005 Sierra Club v. EPA 18cv3472 NDCA 4 of 4 Tier 10 Alaska Department of Natural Resources Attachment F Page 138 of 230 ED 002061 00172725-00138 Go to Table of Contents Guidelines for Cooperation with the Alaska Dam Safety Program Appendix B Example of Certificate of Approvai to Operate a Dam Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 139 of 230 ED 002061 00172725-00139 Go to Ta ble of Contents DEPARTMENT O F NATURAL RESOURCES DIVISION OF MINING, LAND AND WATER DAM SAFETY AND CONSTRUCTION UNIT Certificate of Approval to Operate a Dam The State of Alaska under AS 46.17, and the regulations adopted under this statute, grants to: Dam Owners, Inc. The approval to operate the following structure on _ _ _ _ _ _ Creek in accordance with the terms and conditions contained in this certificate: Name of Dam (NID ID#AK00XXX) The location of this project is: T X X S , RXXE, SXX,_________Meridian The holder of this certificate shall: Operate th e ___________ Dam and appurtenance works in accordance with accepted practice and Version X of the Operation and Maintenance Manual dated ______and approved by the Department concurrent with this certificate. Except for the claims or losses arising from the negligence of the State, defend and indemnify the State against, and hold it harmless from any and all claims, demands, legal actions, loss, liability and expense for injury or death of persons, and damages to or loss of property, arising out of or connected with the exercise of the approval granted by this certificate. Comply with all applicable laws, regulations and conditions. Allow representatives of the Department to inspect the work and records covered by this certificate at all times determined necessary by the Commissioner. Follow special conditions that apply to the operation of this dam as found in Attachment A, attached hereto and made a part hereof. Certificate No. Sierra Club v. EPA 18cv3472 NDCA 1 of 3 Tier 10 Date Attachment F Page 140 of 230 ED 002061 00172725-00140 Go to Table of Contents CERTIFICATE OF APPROVAL TO OPERATE A DAM Name of Dam This Certifcate of Approval to Operate a Dam supersedes any other Certificate of Approval to Operate a Dam for th e ______Dam and shall become invalid 30 days after the Periodic Safety Inspection date specified under Attachment A, A valid certificate shall be issued with revised special conditions based on information contained in a current Periodic Safety Inspection Report approved by the Department and dam safety regulatory standards current at the time of the inspection. This Certifcate of Approval to Operate a Dam is granted subject to the pertinent statutory provisions in AS 46.17 and in Administrative Regulations in 11 AAC 93. APPROVED BY: TITLE: SIGNATURE: DATE: Charles F. Cobb, P. E, State Dam Safety Engineer Division ofWining, Land and Water ____________________________ ____________________________ State of Alaska ) )SS. Third Judicial District ) ........................... This is to certify that on __________ ______ __, 200X, before me appeared ___________________________________ , known by me to be the Director or Authorized Representative of the Division of Mining, Land and Water, Alaska Department of Natural Resources, and acknowledged to me that this Certificate of Approval was voluntarily executed on behalf of the State of Alaska. Notary Public in and for the State of Alaska My Commission expires: _______________ Certificate No. Sierra Club v. EPA 18cv3472 NDCA 2 of 3 Tier 10 Date Attachment F Page 141 of 230 ED 002061 00172725-00141 Go to Ta ble of Conten ts CERTIFICATE OF APPROVAL TO OPERATE A DAM Name of Dam Attachment A - Conditions 1. Inspect and maintain the _________ Dam in accordance with the procedures outlined in Version X of the Operations and Maintenance Manual d a te d ______ . Inspect the dam after all significant seismic or precipitation events. Maintain records of the inspections. 2. Perform a Periodic Dam Safety inspection as required by 11 AAC 93.159 on the _________ Dam and appurtenance works by DATE. The frequency for Periodic Safety Inspections shall be a t ___year intervals as required by regulation for a Class downstream hazard dam. 3. The Periodic Safety Inspection must be performed by an approved, Alaska registered, professional engineer. Approval of the inspection engineer and the scope of the inspection must be obtained in advance from the Department. 4. An Emergency Action Plan (EAP) shall be maintained for the ____ Dam in accordance with the document titled "Federal Guidelines for Dam Safety: Emergency Action Planning for Dam Owners" (FEMA 64) published by the Federal Emergency Management Agency (October, 1998). The EAP shall be reviewed, exercised, and revised in accordance with the following schedule: DATE Annually By June 30, 200X By September 30, 200X By June 30, 200X ACTION Internal review (distribute updated pages) Orientation, drill or table top exercise Revise as needed and redistribute Subsequent level of exercise for revised plan 5. Notify Dam Safety at least 14 days prior to the E A P exercises. Certificate No. Sierra Club v. EPA 18cv3472 NDCA 3 of 3 Tier 10 Date Attachment F Page 142 of 230 ED 002061 00172725-00142 Go to Table of Contents Guidelines for Cooperation with the Alaska Dam Safety Program Appendix C Example of Certificate of Approvai to Construct a Dam Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 143 of 230 ED 002061 00172725-00143 Go to Table of Contents r e i e p e M r w [:r ATTA ...A AA y\ A (Cl A\ Al DEPARTMENT OF NATURAL RESOURCES DIVISION OF MINING AND WATER MANAGEMENT DAM SAFETY AND CONSTRUCTION UNIT Certificate of Approval to Construct a Dam The State of Alaska under AS 46.17. and the regulations adopted under this statute, grants to: Dam Owners, Inc. The approval to construct the following structure on th e ________Creek in accordance with the terms and conditions contained in this certificate: Name of Dam The location of this project is: Section Township Range Meridian The holder of this certificate shall: Construct the dam and appurtenance works in accordance with the plans and specifications dated______approved by the Department concurrent with this certificate. Except for the claims or losses arising from the negligence of the State, defend and indemnify the State against, and hold it harmless from any and all claims, demands, legal actions, loss, liability and expense for injury or death of persons, and damages to or loss of property, arising out of or connected with the exercise of the approval granted by this certificate. Comply with all applicable laws, regulations and conditions. Allow representatives of the Department to inspect the work and records covered by this certificate at all times determined necessary by the Commissioner. Follow special conditions that apply to the construction, modification, removal, or abandonment of this dam as found in Attachment A, attached hereto and made a part hereof. Certificate No. Sierra Club v. EPA 18cv3472 NDCA 1 of 3 Tier 10 Date Attachment F Page 144 of 230 ED 002061 00172725-00144 CERTIFICATE OF APPROVAL TO CONSTRUCT A DAM Name of Dam This Certificate of Approval to Construct a Dam is granted subject to the pertinent statutory provisions in AS 46,17 and the Administrative Regulations in 11 AAC 93. APPROVED: ____________________________________ TITLE: State Dam Safety Engineer Division of Mining, Land and Water State of Alaska ) )SS. Third Judicial District ) This is to certify that on __________________ , 200X, before me appeared _________________________________ , known by me to be the Director or Authorized Representative of the Dam Safety and Construction Unit of the Division of Mining, Land and Water, Alaska Department of Natural Resources, and acknowledged to me that this Certificate of Approval was voluntarily executed on behalf of the State of Alaska, Notary Public in and for the State of Alaska My Commission expires:______________ Certificate No, Sierra Club v. EPA 18cv3472 NDCA 2 of 3 Tier 10 Date Attachment F Page 145 of 230 ED 002061 00172725-00145 Go to Table of Contents CERTIFICATE OF APPROVAL TO CONSTRUCT A DAM Name of Dam Attachment A - Conditions 1. Notify the Dam Safety and Construction Uni! at least six (6) weeks in advance of the beginning of the excavation for the foundation of the dam. 2. Submit for review and approval, the following pre-construction plans: Water diversion plan Erosion and sediment control plan Pollution control plan 3. Submit a construction schedule, including mandatory inspection points. 4. Submit a construction quality assurance and construction quality control plan. 5. Submit for review and approval, plans and specifications for any modifications to the dam or appurtenant works approved by this certificate. 6. All work associated with the dam and appurtenant works must be supervised by an engineer with experience in the construction of a dam. 7. Submit record drawings, a completion report, an Operation and Maintenance Manual, and for Class I and II dams, an Emergency Action plan, within 30 days of substantial completion of the project. 8. No water may be impounded behind the dam until a Certificate of Approval to Operate a Dam is issued by the department: A Certificate of Approval to Operate a Dam, including any pertinent terms and conditions, will be issued upon review and approval of the submittals required under the previous condition. 9. Commence construction by the first day of June of the second calendar year after the date of this certificate. If construction does not begin by this date, an updated application must be submitted for review and approval by the Dam Safety and Construction Unit, including application fees required under 11 AAC 05.010. Certificate No. Sierra Club v. EPA 18cv3472 NDCA End of Attachment A 3 of 3 Tier 10 Date Attachment F Page 146 of 230 ED 002061 00172725-00146 Go to Table of Contents Guidelines for Cooperation with the Alaska Dam Safety Program Appendix D Project Data Sheet Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 147 of 230 ED 002061 00172725-00147 Go to Table of Contents PROJECT DATA SHEET a, general Dam Name ^......... NsD Numoef Hazard Potential Class _ _ _ _ __ Purpose..... Year Busts Yea* Modiied__ __ ________ __ Location......m..... ^ ^ ^ ^ _... Reservoir Name R r or Creels Name__ _ _ Owner, __ ____ Owner Contact a Type..... Core Type Crest Length ,,........ Croat Wisstn Crest E l e v a t i o n _ __ _ _ _ Crest Height (from d/s toe) w ................ . _ ^ Hydraulic Height c, p m m & m spillw ay Type tscalso' Spillway Creal Elevation Top Width Rotten Wsdh <angth Discharge Capacity at Dase Dost 0, esfeERSENCY SPILLWAY Type Location Spillway Crest Eisvot on " op Wfett? Bottom Width Length Discharge Capacity at Dam Crest _ 1 of 2 Sierra Club v. EPA 18cv3472 NDCA Tier 10 m. lattong (GPS) feat feat feet fast feat feet feet feet feet cfs feat feet feet feet cfs smmtm Attachment F Page 148 of 230 ED 002061 00172725-00148 Go to Table of Contents PROJECT DATA SHEET mo Ho E. OUTLET WORfiS Type Location inlet invert Elevation Outlet Invert Elevation Diameter Length ______............ .............. ......... Outlet Type Discharge Capacity at Dam Crest ?* RESERVOIR Normal Water Surface Bewaaon __ .. ____.......... _____........ __ Norms Storage Caoacity Maximum ifVaiar Sybase E'evanon Maximum Storage Capacity _____ ___ ____........ _____ Maximum Surface Area at Dam Cres1 Surface Area at Spillway Crest G. HYDROLOGY Drainage Basin Area Ayerage Annual Rainfall 10Yea'-'24 Hour Rainfall 100 Year Flood_ Probatste Maximum Precipitation Pmtebte Maximum Flocd flood of Record....... Inflow Design Flood feet feet inches feet cfs feet acre-feet feet acre-feet acres acres sq, miles inodes instes os inches cfe cfe cfs Sierra Club v. EPA 18cv3472 NDCA 2sl2 Tier 10 mmcm Attachment F Page 149 of 230 ED 002061 00172725-00149 Go to Table of Contents Guidelines for Cooperation with the - - - . A la sk a Dam Safety P ro gra m Appendix E Sample Outline for a Simple Operations and Maintenance Manual for a Small Dam Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 150 of 230 ED 002061 00172725-00150 Go to Table of Contents SUGGESTED OUTLINE FOR OPERATIONS AND MAINTENANCE MANUAL FOR SMALL DAM (Incomplete Draft) Title: Operations and Maintenance Manual for ____ Dam in ____ , Alaska Revision l.X Date I. Operations a. Identify and briefly describe facility, systems, valve locations and functions, instrumentation, alarm systems, etc, b. List critical operating limitations, e.g. maximum wfter levels, drawdown rates, discharge flows, etc. c. Project Data Summary Sheet II. Maintenance a. Clear brush on dams, dikes, and abutments annually, etc. (and other recommendations in current Periodic Safety Inspection) b. Exercise mechanical equipment, gates, valves, etc. and service or lubricate (as required) weekly, monthly, quarterly, semi-annually, etc. Include service instructions or reference sendee manual. d. Other maintenance items such as clear spillways, clean intakes or trash racks, paint handrails, grade access roads, etc. III. Routine Inspections a. Identify routine inspection items and schedule for inspection. Include specific details on how the inspection should occur, if required. b. Complete the attached routine inspection checklist weekly, monthly, quarterly, semi-annually, etc, and after major precipitation or seismic events and file at specified location. c. Monitor instrumentation (piezometers, weirs, thermistors, survey monuments, etc.) weekly, monthly, annually etc. IV. Unusual Occurrences a. High water: Open spillway gates, low level outlets, etc. b. Excessive seepage: Lower water level, add fill, etc. c. Notify the following if any abnormalities are noted: 1. City Engineer or Public works director, etc. 2. State Dam Safety Engineer 907-269-8636 Attachment: Project Specific Routine Visual Inspection Checklist Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 151 of 230 ED 002061 00172725-00151 Go to Table of Contents My Dam Weekly Visual Inspection Checklist Date Reservoir level a. Main Dam 1. Downstream slope 2. Seep at left abutment 3. Seep at toe Circle One OK Not OK Clear Cloudy Clear Cloudy Remarks Weir level b. Spillway 1. Primary spillway 2. Emergency spillway c. Outlet Works 1. Intake screen 2. Sluice gate OK Obstructed11 OK Obstructed Clean Clogged Open Closed e. Other appurtenances 1. Gates 2. Restricted access signs f. Additional comments Locked Legible Unlocked Shot up g. Actions required h. Inspected by i. Reviewed by supervisor Date Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 152 of 230 ED 002061 00172725-00152 Go to "['able of Contents Guidelines for Cooperation . with the - - / Alaska Dam Safety Program Appendix F Performance Parameters for Dam Safety Monitoring An excerpt from the notebook titled Safety Evaluation o f Existing Dams Seminar, U.S. Bureau of Reclamation/ Denver/ Colorado/1999. Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 153 of 230 ED 002061 00172725-00153 Go to Table of Contents PERFORMANCE PARAMETERS FOR DAM SAFETY MONITORING byiiay Statelet) Larry V a n Thun, Gregg Scott, and Jim Boernge """'v T~'Q.STBureau of Reclamation, Denver, Colorado Introduction To promote efficient an d effective monitoring for dam safetv purposes, the Bureau of Reclamation has begun developing and documenting performance parameters for each of sts darns, h is antieipateo that these documents will be the foundation of the future Reclamation dam safety program, in a nutshelf, the performance paiamater document addresses the question; "What should be done to pioperly look after the dam m the future, from a dam safety perspective, given what we know today?" To adequately and appropriately address this question, the following process is followed: 1, Identify the most likely failure modes for the dam, 2, Identify the key parameters to monitor that will provide the best indication of the possible development of each of the Identified failure modes, and define an instrumented and visual monitoring program to gather the necessary information and data. 3, Define the ranges of expected performance relative to the Instrumentsd and visual monitoring program, nd define the action ta be taken in the event of unexpected performance. Each of these steps in the process wilt be discussed briefly slow, and then six of the most commonly encountered failure modes will be presented and discussed fo illustrate the concepts, approach, and process. The goal Is to prevent circumstances where uncontrolled releases from the reservoir cause loss of life or significant economic losses m downstream areas. The most effective initial step toward this goal is to identify potential failure modes for the dam. This is done in light of the information and analyses that ere currently available concerning the dam and damsite, the current state-of-the-art in dam design and evaluation, and the record and available knowledge regarding past dam failures. As so initial step, a careful review is made of the fallowing $rtospeoific {formation; 1, Sits geologic oondWons, 2, Design of the dam and appurtenant features. 3, Construction methods and records. 4 , Performance history, based pri instrumentation data and visual observations. Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 154 of 230 ED 002061 00172725-00154 Go to Table of Contents Si Current design earthquake and flood loadings, A focused discussion involving individuals that hove had signriicsm involvement with tiie dam ie.g had involvement during dvsign/cunstiuction, performed analysis work, performed site inspections, reviewed instrumentat'cn data, etch can be a very effective means of developing a list of potential rasiure modes, Synergy during such a session can lead ;o results superior to those that might otherwise be achieved. Clearly the failure mode evaluation is very site specific. The search is for failure modes that are physically possible Cor cannot reasonably be ruled out) given the information available. The potential failure mechanisms need tc be described as precisely and specifically as possible,, so that the remainder of the performance parameter process can be effectively earned out. The most prohaole locanonfsi for development of each potential failure mode needs to Pe specifically identified, along with the manner in which the failure mode would likely initiate. The identified failure modes are presented in order of apparent threat or likelihood, to help establish which modes- deserve the most energy, effort, and attention in the monitoring efforts. It is important to understand that the identification of potential failure modes does not necessarily mean they are likely to occur. If the likelihood was viewed to be more probable than "remote," then a dam safety deficiency exists, and dealing with the situation by merely employing future attentive monitoring would not Pc appropriate. Structural modification of the aam and/or use of a well-designed Early 'Warning System {EWSh if appropriate, would be indicated in these cases. The concept of being '`pnysicaiiy possible, but of low likelihood" may be difficult in some instances, but the fundamental reality is that there Is inherent risk associated with every dam (generally very fowl, no matter how apparently wall-designed and "safe" it may appear, and it 1$ that reality that is being addressed by a continued vigilant monitoring program for the dam, Identify Key Parameters To Monitor Relative To Each Failure Mode The next step in the process is to look at sen potential failure m o d e en d a s k the question; "What clues should wa look for to detect the possible development of this failure mode?" The clues can fall into two categories; (1J those that provide earlywarning of the passible onset o# the failure mode, and (21 those that indicate the presence of conditions conducive to the development of the failure mode, The monitoring of the parameters can be accomplished by observation for specific visual clues, and/or by instrumented monitoring. In addition to specifying what parameter should be monitored, how, and where, the monitoring frequencies also need to be establishes. It is important from me standpoint of efficiency and credibility of the monitoring program that the scale of the program be appropriately balanced with the risks end consequences associated with the potential failure mode. Appropriate explanations of the program should be provided to those that will pertorm and/or pay for the monitoring so as to give d good understanding of why the program is justified. It is vital that the monitoring program be effective, but efficiency and common sense is also important so as to achieve acceptance and sustainability. 2 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 155 of 230 ED 002061 00172725-00155 Go to Table of Contents It an instrumented monitoring program s already in place at the dam, it Is necessary to determine winch instruments should be retained, which are of limited current value and are no longer needed,, what additions* instruments ere needed, and what adjustments should be made to existing reading frequencies. It is typical to utilize existing Instruments in the newly defined monitoring program to the extent possible, both for economic reasons and to take advantage of the existing database for these Instruments that provides a valuable baseline for comparison with future data. identify Expected And Unexpected Performance ibis stage of the process is intended to make the work of the 'operators ' ct the routine monitoring program efficient end effective. Regarding routine visual inspections performed by on-site personnel, definition is proviaed concerning what observations wouid oe in line with expected performance, and what needs to be promptly reported eno evaluated. Regarding instrumented monitoring, definition is provided concerning whs: readings are within the bounds of expected behavior, and what readings should bo promptly chocked, and investigated farther if confirmed. Routine computerized real time comparison of instrument readings to established brmts, that are a function of reservoir level, failweter level, air temperature, and/or other relevant parameters, is in no way mtendeo to replace necessary human reviews of data, but instead can serve as a valuable "coarse sieve'' for the data to allow much of the anomalous data to be readily identified. iilystiation of the Methodology Using Example Failure Modes Six of the most commonly encountered potential failure modes are discussed below to illustrate the thought process associated with the three-step approach to developing performance parameters, and to promote better understanding of these important failure modes. The firs: two relate to failures that can occur under normal operating conditions, white the test four concern failure under extreme loading conditions (floods and earthquakes). Example FailureMpdi. 1 - Piping q? S yfesyrfi Cfi,Jaim .^..Em fearrkrrm nt Cgre.Maferials Historical experience and performance parameter failure mode Identification to date show that by far the most prevalent potential failure mode tor an embankment dam, absent an extreme loading condition due to an earthquake or flood, is the threat of pining or subsurface ercsion of embankment core materials, Current embankment design practice adequately protects against this failure mode, but older embankments generally do not .corporate all the necessary defenses, The following questions can ha used to assess the adequacy of the protection against this failure mode; 1, Where embankment core material was placed directly upon bedrock, was the surface of the bedrock treated with s;ush grouting to seal off all exposed Joints and fractures? This would prevent transport of core materials into the bedrock. Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 156 of 230 ED 002061 00172725-00156 Go to Table of Contents 2, Where embankment core material was placed diieetly upon bedrock, was the surface of the bedrock excavated and/os treated with dental concrete to provide a reasonably regular surface upon which to place the embankment (a,g. free of significant "stops''}? This would reduce fee nsk of development of cracks in the core material due to arching effects ano/or differentia! settlements, 3, Where embankment core material was placed directly upon overburden materials, was the filtering capability of the range of overburden materials to be encountered checked relanve to the core material, and were sufficiently thick filtering zones provides, where needed, to prevent transportation of com material mm the overburden materials by seepage flows? 4, In the embankment, was a filter aona provided downstream of all pomoos of the embankment core, and do all embankment zones downstream ot the embankment core meet current filter criteria requirements with the tone immediately upstream? 5, Were properly filtered drains provided to safely intercept and discharge seepage that passed through the embankment? If these questions reveal that the necessary defenses are not totally present, or u It >$ unknown or unclear it the necessary defenses ere in place, then potential failure mechanisms associated with piping or subsurface erosion need to be addressed by the routine monitoring program. The severity of the threat posed by the identified failure mechanisms may be reduced if one or more of the ^allowing conditions ate present; 1, The embankment core material has significant plasticity, such that if is not easily erodibie. 2 , The hydraulic gradients are net high in the areas of concern* 3, The seepage quantities are low, such that if erosion of core materials Is taking olace, failure of the embankment would taka a long time, providing ample opportunity for recognition and response to the developing problem, 4 , The seepage path involves flow through joints in competent rock, meaning that the cross-sectional area of the flow Is affectively limited by the site of ihe joints, and can not readily increase over time, 5, An exit point for the seepage, that permits removal of the material transported by the seepage flow trom the site, does not exist, ane areas for possible tedeposltion of transported material, such as within coarse embankment zones or within coarse foundation overburden deposits, are limited in terms of volume oj access, Such a failure mechanism vrould be self-limiting, as in time the downstream end of the seepage path would become increasingly obstructed, and no alternative path would foe available that has an exit point or large capacity for redeposition of materials. 4 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 157 of 230 ED 002061 00172725-00157 Go to Table of Contents in addition to the above discussion of .general' site conditions that could give rise to problems, several special cases relating to this potential failure mode might fee encountered. One special ease is for the piping or erosion to occur along the outier works, spillway, or other appurtenant structures, particularly in the event of differential settlement or movement between the embankment and the structure that produces gaps, areas of lesser seepage resistance, etc. In some instances cracks or flows in the appurtenant structure may provide an exit point for seepage flows, though the development of toe failure mode typically wauid fee significantly constrained by the available flow ares at the exit point. In other rare instances, flaws, cracks, or leaks in an appurtenant structure could lean to the introduction of seepage water into the embankment at high pressure, with great potential to move even fairly erosion-resistant materials, due to the high hydraulic gradients involved. When these "special" exit and entrance points are not present, and when a downstream liner zone has been provided jthot meats current filter criteria!, then the potential for this special case of the failure mode is greatly reduced, if not essentially eliminated. Another special case is that the filter zone immediately downstream or toe core material is sometimes not extended all the way to the crest of the dam, as the anticipated level of the phreatic surface is far below the dam crest elevation a* the downstream edge of the core material, At many such sites there is the possibility of development of transverse cracks near thfe..om.s.i, extending to a depth below the maximum reservoir elevation, due to desiccation of core materials, differential settlement due to abrupt changes in embenkmem/foundation contact elevation, seismic shaking, or other causes. Seepage flow through such transverse cracks could erode core material and carry it into and through the downstream shall materials as these zones rarely meet current filter criteria with the core material. Yet another special case involves seepage flow through untreated joints in the foundation bearock or abutment rock, at and just beneath the embanfcment/foundation contact. Such flows could contact and carry cote material into the joints in the foundation. Effective toundation grouting could greatly reduce the risks associated with this mechanism, but com ungrouted joints must always foe assumed, This "contact" mecnanism is a lesser threat than the typical failure mechanism shat postulates flow passing from the core material into the joints in the foundation laeross, not along the interface!, The "contact" mechanism is a lesser threat because it generally would be expected to progress at: a slower rate then would the "typical" mechanism:. With a good understanding of the possible failure scenarios associated with this potential failure mode, fbe locations of prime concern relative to routine dam safety performance monitoring should foe clear. Parameters to monitor are as follows; 1, Visual observation to? evidence of materials transport with seepage or drain flows. Where natural sediment trap locations are available, sucn as >n manholes and at the stilling pools in front of weirs, they should be carefully monitored {after being cleaned out so as to start with a "clean slate"!, General awareness should be maintained fcr discolored seepage or drain S Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 158 of 230 ED 002061 00172725-00158 Go to Table of Contents water. and for any evidence- of material deposite in the vicinity of- the flowing water, 2. Visual observation fot new seepage areas, for changes in the conditions at exiting wet areas or seepage areas that cannot be quantitatively monitored, and for transverse cracks at tea crest of the darn, if the failure mechanism involves flow through joints in the bedrock, the visual observations should be extended a significant distance downstream of the embankment, as new seepage areas will not necessarily exit near the toe or groin of die embankment, 2. Flow rate monitoring at toe drains, other drains, and known seepage areas that can be quantitatively monitored, Anv evidence of increased flows at comparable reservoir elevations would be cause for concern and would need to be promptly investigated, 4, Monitoring of appropriately located piezometers and observation wells for any changes in their historical relationship with reservoir elevation, and for changes in the relative piezometric levels at adjacent instruments. The water pressure date, being representative of conditions over only a limited area, are frequently of lesser value than the information obtained by the three previously noted methods, that are mere global in scope. Note that monitoring relative to item 1 above provides direct evidence of the occurrence or non-occurrence of this potential failure mode. Ail the other monitoring described above provide indirect evidence concerning this failure mode, The monitoring frequencies for items 1-3 above generally are all the same, as typically thev should all be done during the same "tour" of the dam and appurtenant structures. Frequencies can range from 4 times oer year for low risk situations to weekly or several mes par week for high risk circ u m s ta n c e s - A monthly frequency would be fairly typical- For item 4, monitoring frequencies typically are the same, or somewhat less frequent than for the other items, with a minimum frequency of 3 timas per year tc establish a basic correlation with reservoir elevation. Monitoring frequencies for item 4 may be less frequent than for the other items because the other items typically provide the most valuable information, and provide monitoring coverage of the entire dam, as opposed to only limited areas, as noted previously. Since the risks of this failure mode increase with increasing reservoir elevation, it is common to institute more frequent monitoring when the reservoir Is unusually high. Historical experience and performance parameter failure mode Identification to date show that bv far the most prevalent category of potential failure modes for a concrete dam are those relates to loss of foundation support for the dam For both gravity and arch dams, adequate support from the rock against which the dam was built is fundamental to the structural well-being of the dam. For arch dams, thrust support provided by the abutments is particularly crucial, given the high loadings transmitted to S Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 159 of 230 ED 002061 00172725-00159 Go to Table of Contents them. Significant loss of this foundation support induces concrete stresses for which the dam was not designed. This Seeds to cracking of the dam, and potentially its failure. Sliding along weak discontinuities in the foundation rock is the sricsi commonly encountered scenario related to this potential failure mode. Sliding is most likely to occur" tl) parades to bedding planes or planes o' schisiocity, 12] on low strength layers within the foundation {such as scale or bentonite seams), 13) at contacts between different rock units, or >4.) at other continuous {or nearly continuous) planes of Sow shear strength in thw foundation, for a block of rock to move, it must have "release ' planes on all sides. Such release planes typically are formed by jointing in the rock, possibly in combination with fault or shear cones. The presence of reservoir seepage wafer in the rock leads to lower affective normal stresses, and therefore lower frictional resistance, along the slide plane{s|. The water can also, in some instances, result in shear strength loss in foundation materials, Another potential scenario related to this failure mode Is for structural distress to the asm to result from significant differential compressibility of rock units in the foundation, that were not accounted for in the dam design. Resulting differential movements in the dam could oversfress the concrete, leading to cracking and potentially dam failure. This failure scenario is mainly relevant to relative to dams where potential future leads imposed on the foundation rock may be significantly greater man loads experienced to date. Obviously a good understanding of toe site geology re important relative to this failure mode, Where geologic information is not comprehensive for a site, it is important that reasonably possible geologic defects be'appropriately considered if they cannot be ruled out, Wan o good understanding of the possible failure scenarios associated with this potential failure mode, the routine dam safety performance monitoring: can be established Key monitoring parameters are as follows; 1. Visual evidence of structural distress to the dam would be direct evidence of the possible development of this failure mode. Evidence of offsets at contraction Joints or new cracking of the dam {apparently structuias rather than temperature-related] would be the primary visual evidence of concern Both the exterior faces of the dam and the interior gallery surfaces should be observed. Scribing sets of crisp lines across contraction joints ss a simple, cost effective way to aid visual monitoring tor offsets. Scribe lines should be provided tc detect both horizontal end vertical relative movements. 2, Instrumented evidence of structural distress to the dam would also constitute direct evidence of the possible development of this failure mode. Unusual settlements or deflections of the dam, that vary from the historical patterns of behavior, would be evidence of concern. Also, any instrumented monitoring of relative movements at contraction joints (or other locations! that departed from historical trends would be evidence of behavior that would be ofeonoorm 7 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 160 of 230 ED 002061 00172725-00160 Go to Table of Contents 3, Evidence of changed water pressure conditions in the foundation would increase the likelihood of envelopment of this failure mode. Such evidence could include new seepage areas on the abutments, increased seepage Hows on the abutments, increased or decreased seepage flows trom drams in th e dam, as well as increased water pressures measured in the abutments or beneath the dam, Such evidence would not he direct evidence of the possible development of this failure mode, hut instead would only tunicate an increased likelihood of Its development. Stability analyses could give indications of water pressure levels that produce unacceptaote calculated factors of safety against movement, and therefore would he of senous concern. The monitoring frequencies for the key monitoring parameter noted above generally would ail he the same, as typically tney should ail be performed during the same "toy?" of the dam, A frequency of tour times per year would be common. Surveying of measurement points may b e le s s frequent if other means of monitoring for structural movements are also available at the dam, In this case, annual surveys of the measurement points might he typical, though circumstances might indicate that even this monitoring frequency is not warranted, and surveys performed every several years may he sufficient, For arch dams, it is not unoommon to read piumblime instruments monthly so that the dual impact of seasonal temperature variations and reservoir level variations on deflection data can be better accounted for and understood when trying to determine it historical deflection patterns are being foiioweo. Example Failure Mode 3 - Flood-Induced Failure of an Embankment Dam A flood can lead t o the failure of an embankment dam in a number of different ways: 1. The dam: is overtopped, end the overtopping flows erode the crest and downstream slope such that breaching of the dam results. .2, Peak water levels are fust below the crest of the dam, and *spfashover, * due to wind setup and wave action, causes erosion that leads to breaching of the dam, 3. Peak water levels are pat below the crest of the dam, but above the top of the embankment core material that lies more than a foot or two below the dam crest elevation. Flow through pervious materials above the top of the core material erodes the core material, eventually leading to breaching of the dam. 4, High flows through the spillway for outlet works! lead to damage to the structure, perhaps due to cavitation, or due to erosion of the downstream channel undermining the stilling basin and chute structures. The erosion and damage work their way beck toward the crest structure until finally the structure Is completely lost and uncontrolled release of the reservoir occurs. Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 161 of 230 ED 002061 00172725-00161 Go to Table of Contents 6. High flows through the spillway (or outlet works] are not properly conveyed away horn *he toe of the dam such that erosion of the embankment ensues, leading to undermining and eventual broaching of the dam. The failure scenarios above may occur in combination during one flood event, increasing the potential for breaching of the dam, It s also possible that the spillway and/or outlet works will not be operated as expected during the flood event, due to stuck Of inoperable gates, lacs, of power land backup power!, loss of access to the sue, operator erra?, etc. This may transform a fiooa that could have been safely handled into a flood that causes asm failure. The value of performance parameter work relative to extreme events, such as floods and earthquakes, comes largely from steps taken in advance of the event to recognise and deal with possible deficiencies, so that the failure scenarios can be avoided. Some stow comments that generally apply to all failure modes related to extreme loading conditions Ifloods and earthquakes] are as follows! 1, The routine, monitoring program associated with flood events and earthquake, events generally consists of obtaining s good baseline of pre-event conditions, so that whenever the event may occur, sufficient information is available for comparision to post-event conditions to determine changes that occurred, 2 , Careful monitoring during lesser magnitude earthquake or flood events cep Identify performance problems that could result sn dam failure during a larger event Itbe design event]. Such "full-scale prototype testing" can provide valuable Information, obtainable in no other way, if appropriate advance reparations have been made, to appropriately document performance during these events, 3, In some instances, an Early Warning System IEWS) may be used as the primary defense against loss of life in downstream areas if the reliability of the EWS to minimize loss of fife supports such an approach, if an EWS is used, the performance parameters should define a program of periodic operational checks of the EWS to ensure that it functions as designed in the event that it is needed. The above comments apply to each of the next throe failure modes that will he discussed, hut will not be repeated in those sections. Obviously, relative to flood events at embankment dams, it is important to be dealing with current crest elevations of structures, rather than design elevations, as postconstruction settlement and camber allowances need to be considered. Cresr surveys can identify Sow spots on the embankment where flood damage may first occur. Embankment areas near the abutments frequently are the Sow areas because little or no camber was provided. Those areas near the abutments would be of particular concern as erossve flows down the groins would be concentrated into a small area. Heightened instrumented monitoring is generally warranted during a flood event, as the likelihood of failure mode scenarios involving high uplift pressures, piping gnd/or subsurface erosion, etc. increases. Daily visual monitoring for evidence of onset of Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 162 of 230 ED 002061 00172725-00162 Go to Table of Contents these failure modes, as w e ll as for the five flood-e la te d failure mode scenarios noted above, typically is wan anted. Following the flood event, a thorough inspection of the darn and appurtenant structures should be performed, and all instruments should agam be read, if there are indicat.ons of possible settlements or defied inns of embank men?? or appurtenant structures, any measurement points located on them should be promptly surveyed. Cam ple,Eajum .M ^_.i..:r..^ An earthquake can lead to failure of an embankment dam in three basic ways: 1. Deformations of the ernbankment/foundation due to seismic shaking lead to lowering of tne dam crest and overtopping of the dam at one or more locations. The deformations may be due to liquefaction of embankment and/or foundation materials, potentially resulting in a large flow slide, However, significant deformations of the dam and lowering of the dam crest can also occur without the occurrence of liquefaction. Depending on the deformations experienced, and the reservoir level, overtopping of the dam could rapidly lead to complete dam failure, Alternatively, rapid loss of reservoir water may not occur initially, instead, over time overtopping flow at one or more locations would erode the emfcamcment, eventually resulting in a "full breach" condition. Then, raoid loss ot the remaining reservoir water would occur. 2. Deformations' of the embonkmem/foundatlon due to seismic shaking for fault displacement) lead to transverse cracks through the embankment, that lead to erosion of embankment material by seepage flows following the cracks. This situation could progress rapidly to breaching of the dam and dam failure. However, if the seepage quantity through the new crack is not high and/or the core material of the dam is plastic and not highly erodible, tt is possible that ft may take a fair amount of time before dam failure would occur {if failure would occur at ail). If an appropriately designed filter zone has been provided downstream of the embankment core material that would not "sustain" a crack {would collapse rather than stand as an open crack), then the risk of this failure scenario ts negligible. Similarly, if the core material itself is "self-healing" and would not likely sustain a crack, then the m$K of this failure scenario diminishes substantially. 3. Seiche waves overtopping the dam. This situation is most relevant when the fault that experienced movement is within the reservov, w*tb a significant ponton ot the reservoir being on the 'up throated' side, while the dam, or a pardon of the dam, was on the side of the fault that was Kdowntbrusfed:T! A rapid earthquake response, leading to commencement of reservoir evacuation and/or evacuation of the downstream populace could mitigate damages relative to scenarios 1 and 2, since actual catastrophic release of the reservoir could potentially lag the aartnqusk by hours or even days. Failure scenarios 1 and 3 may result in raps TO Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 163 of 230 ED 002061 00172725-00163 Go to 'Fable of Contents failures where only a fully functioning Early Warning System would have: any chance of mitigating adverse downstream consequences, and tnen only if there was adequate time between the time when the dam breached and when the flood wave reached ina population at risk. The routine monitoring program associated with an earthquake-relaled failure of an embankment dam generally consists of having adequate baseline information relative to: ns seepage data and conditions at the site, l2i ?he general overall appearance cf the dam and appurtenant structures, ?3| survey data from available measurement points on the dam and appurtenant structures, 14) data from any other deformationmcmitonng instruments that may be present at the site, and 16) water pressure data from piezometers and observation wells at the site, immediately following an earthquake, a thorough inspection of the dam and appurtenant structures should be performed, and the rsstrumems should be promptly read, If there are indications of possible settlements or deflections of embankments or appurtenant structures, any measurement points located on them should be promptly surveyed. If there are any instruments indicating elevated water pressures, potentially due to liquefaction of embankment nr foundation materials, then these instruments should be read daily until they stabilize and aooiticnaf visual Inspections should be performed as appropriate, if the reservoir is not at a high level at the time of the earthquake, it is important to recognize that failure scenario 2 may not begin developing until a future time of higher reservoir elevations {when water can pass through cracks relatively high u p on the dam). Depending on the apparent level of damage sustained by tne dam, it may be appropriate to inst-tute more frequent routine monitoring of the dam until satisfactory perrormancs at high reservoir levels has been demonstrated. Example Failure Mode S - Flood-Induced Failure of a Concrete Sam In virtually al* cases, the dam safety concerns associated with overtopping of a concrete dam relate to possible erosion of the foundation of the dam by the overtopping flows that impinge near the dam/foundation contact. Such erosion could undermine the dam, causing loss of foundation support, structural d is ^ is T a ^ Z r TM eventuan3iEifeZi.lfaajiam, Also, it is conceivable that the erosiorraS"'underminiHg, could lead to release of the reservoir at the location of undermining, with the dam budging over ihe "gap" in the foundation. Judging the degree of erosion of foundation materials that may occur during a limited period of dam overtopping, and the consequences this may have on the dam, is often very difficult. Consequently, it is important to be well-prepared to monitor and document what occurs during a lesser flood event at the site, so that analyses relative to larger events can be more definitive. Having on file a good qualify aerial survey of the demsste, along with adequate photographic documentation of foundation areas where overtopping flood flow may impinge, will provide adequate information concerning pre-flood site conditions. During a flood, there may be concerns about potential damage to the spillway or outlet works under high flow conditions:. Damage resulting from cavitation typically would be 11 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 164 of 230 ED 002061 00172725-00164 Go to Table of Contents the primaiy c o n c e rn , though erosion an a undercutting, beginning at the outfall Soeatico, may also be of concern. Such damage could lead to greater overtopping depths, and a longer duration of overtopping, due to less efficient handling of Hows being passed than expected. This conceivably could transform a flood event that the dam theoretically could handle wtshout difficulty into a failure situation along the lines assented above, it is also possible that damage to a tunnel conduit {spillway or outset works) could directly threaten the structural integrity of the dam if the location of sucn potential damage is such that It could negatively impact the abutment/toundation support that the dam relies upon. Following a flood, a thorough inspection of the dam and darnsite should be performed, and all the instruments ar th e site should be reed. If there are indications of possible settlements or deflections of the darn, any available measurement points on the dam should be promptly surveyed, if appropriate,, a new aerial survey of the site should be pers'ormad so that the post-flood topography can be compared to the pre-flood conditions. High foundation and abutment water oressures associated with a flood could conceivably trigger a foundation-related failure as described previously relative to Example Failure Mode 2. Consequently it may be appropriate to take frequent instrument readings n m perform frequent visual inspections during the period of flooding to monitor the key monitoring parameters noted rn the discussion concerning Example Failure Mode 2. Example Fallom .M ade 6 ^ i a M ^ Shaking during an earthquakes can lead to three basic eaieiprtes of failures of concrete dams: 1. The earthquake shaking triggers or activates a slide in the foundation. The failure mechanism would be as discussed previously relative to Example Failure Mode 2, The extreme loading condition associated with an earthquake may destabilise a situation that may otherwise be stable under static leading conditions, 2, The earthquake shaking results in high shearing stresses and/or reduced normal stresses at the lift lines in the mass concrete. If the lift lines are weakly bonded or disbonded, then downstream sliding of the u p p er portion of the dam may occur relative to the bas of the dam. ''Keying'' at lift lines and/or contraction joints can substantially reduce the potential for sliding. This failure scenario is really only relevant for gravity dams, since the shape of an arch dam generally would prevent downstream translation of the top half of the dam. 3 The earthooake shaking results m high tensile .stresses in the dam that lead to serious cracking of the concrete. In an extreme case, the cracking is sufficient to allow sliding and loss of a portion of the dam {usually the upper central portipnL which results in a sudden loss of reservoir containment {to 12 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 165 of 230 ED 002061 00172725-00165 Go to Table of Contents the elevation of the bottom of the missing block}. Side release planes ter the block of eoneiere could be provided by contraction jousts in a gravity dam, but generally not in an arch dam d u e to wedging. Vertical cracks ;r- an arch dam typically would be neeoed to provide side release planes. For some dams, the failure mechanisms described In scenarios 2 and 3 above may act in combination to produce dam failure. The routine monitoring psogram associated with an earthquake-fGateo failure of a concrete dam generally consists of having adequate pre~earihquaxe daseline infonmation relative to: (II the key monitoring parmeters identified relative to Example Failure Mode 2, sf applicable, (2s structural cracking of the dam, (35 offsets at cnnrraction joints, |4| survey data from available measurement points on me dam, and (6i data from any other deformation-monitoring instruments that may be present on the dam. Immediately following an earthquake, a thorough inspection of tne dam should bn performed, and all of the instruments at the dam should be promptly read. If there are indications of possible deflections of the dam, any measurement points should be promptly surveyed. Rerfarmanoe Monitoring Program Whan all the various failure modes of concern have been identified, and appropriate parameters for monitoring determined, an integrated program covering ail the parameters that need to be monitored for the dam can be defined. Standard elements of the program are as follows: 1, Routine visual monitoring by on-site personnel.- A one-page (from and back) Inspection checklist form is typically developed, specific to tne needs of each dam. The form is set up such that any question answered with a "YES" means something unexpected nas been noted that needs to be investigated. 2, Routine instrumented monitoring.- To the extent possible, provisions should be made so that data can be checked against the limits of expected behavior at the time the instruments are being read, 3. Periodic examination by inspection specialists,* This represents an opportunity tor a "fresh set of eyes" to look for anomalous performance, particularly relative to failure modes that are not the current focus of attention. Additionally, this represents an excellent opportunity to discuss the failure modes of concern with on-site personnel, and assist them with any questions they may have relative to performing the routine visual monitoring, 4, Earthquake response and flood response,- Performance monitoring actions that are to be carried out In the event of an extrema loading condition are defined. 13 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 166 of 230 ED 002061 00172725-00166 Go to Table of Contents Documentation of Performance Parameters Work The completed performance parameters document indudes discussion of the following topics: HI description of dam and appurtenant structures, (2) site geology, 13) review of design and construction (41 design flood end earthquake loadings. (5| potential failure modes, {SI key monitoring parameters associated with each potential failure mode, {71 discussion of the monitoring program, including locations of instruments, discussion of past performance, and documentation of the revised monitoring program, (8; presentation and discussion of expected performance, including specific ranges of expected values for the instruments, and (Si action to be taken m the event of unexpected performance. Additionally, a "contact Mst" is provided to promote open communication among all involved parties, and a 2-4 page 'Focused Summary" is provided that briefly p r e s e n ts the key points of the document. Several copies of the summery are laminated in plastic for posting at the dam for quick 'eferenoe. ttM pns Learned Fr&m..Pg|fprmi.nsi..gafa i B e ^ Work To..O^^gndJ^hejLJSegim iim 1, Performance parameter work makes clear the importance of routine visual monitoring by on-srte..ggCAOtmal- The majority of the key monitoring parameters relate to visual observations. It obviously is preferable that these observations be made frequently by personnel routinely at the dam, rather than relying upon infrequent visits by inspection specialists. To promote effective performance of the routine visual monitoring program, the performance parameters document needs to clearly present the ''what'* and the ''why." Every opportunity needs to be taken to cultivate and foster the routine visual monitoring program when designers and inspectors have a chance to meet or talk with on-site personnel, 2, On several occasions, performance parameters work has identified items that have been overlooked or inadequately addressed by the dam safety analysssfovaluation work done to date by Reclamation, indicating that employing this process at the start of such work would be a good Idea. It is striking how often questions, such as whether a particular embankment zone meets current filter criteria requirements with the upstream zone, or what is the clay content of the embankment core material, still exist at dams where recent exploration to obtain foundation samples for liquefaction analyses put drill hales through the zones in question, without sampling them. 3, A central premise of performance parameters work is that *you won't find what you aren't looking for.'" This approach is the opposite of Teds put In some instruments and see what happens.* 4, Efficiency, es well as effectiveness, is important in dam safety monitoring work, given current fiscal realities. Scribing crisp, thin lines across contraction Joints of concrete dams to aid visual monitoring for horizontal and vertical relative movements is inexpensive, but very effective. Slaking the itrmts of downstream wet areas is a cheap, effective way to look tor significant changes with time. At the other end of the spectrum, routine 14 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 167 of 230 ED 002061 00172725-00167 Go to Table of Contents chemical analysis of water samples obtained at seepage locations is expensive, yet provides information concerning only a specific moment m time Since sediment transport by seepage flows con be a process that proceeds in 'spurts/' more effective land inexpensive) moritoring for sediment transport can be achieved using continuous monitoring approaches such as observing far deposited materials in stilling pools associated with weirs or specially provided '"catch basins', at sediment trap locations in manholes*: in filter socks placed on discharge pipes, etc, 5, Some Justifiable monitoring of dams cannot be directly tied to a particular failure mode, but instead falls in the category of "general health monitoring," On-site examinations by Inspection specialists every few years ;s an example, as are surveys of measurement points located on the dam and/or appurtenant structures that are performed every few years, or regular seepage monitoring in the galleries of a concrete dam. Monitoring for "gnrai health" opens the door somewhat to possible abuse, so a<fiow cost, high value^test is applied to such monitoring proposals. ' 6, In-depth evaluations of instrumentation data can not only provide valuable insight concerning the performance of the dam (such as patterns of seepage flow through an embankment), but also insight as to whether a particular instrument is providing sufficiently consistent, reliable data that rt is worthy of being retained in the future monitoring program- Plots of reduced instrument readings versus associated reservoir elevations can be particularly valuable for these evaluations. In some instances such plots may look discouraging, but in fact may reflect failings of reading and/or maintenance procedures (that can ba rectified in the futura) rather than failings of the instrument itself, 7. The fact that a dam has experienced many years of apparently satisfactory performance is important information relative to assessing its risks. However, if the monitoring program is not capable of obtaining usetul information concerning the key monitoring parameters, the "satisfactory" track resold has much lass significance, For example, an embankment dam that has significant ponds and swampy areas at its downstream toe may never have given any indication of pipingfoubsurface erosion problems, but since the key monitoring areas can not be effectively monitored, who knows what may be going on unseen. Similarly, if the toe drains foi an embankment dam are not located at a low enough elevation to intercept ail seepage flow of concern, the data collected will provide an incomplete picture of actuel seepage performance, 8. in some eases, significant structures in the "shadow" of more significant: structures receive less dam safety attention than they deserve. Dikes associated with larger dams, and wing dikes associated -with concrete dams, are exemptes of structures that might get more attention if they were independent of their associated, more major structure. IS Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 168 of 230 ED 002061 00172725-00168 Go to Table of Contents iMiiffisat The performance parameters process provides a cost effective means of achieving effective ana efficient darn safety monitoring piograms by providing focus and integration to monitoring efforts. The justification for the monitoring efforts is concisely provided to those who fund the monitoring activities, and to those who perform them, important information can be effectively obtained from and conveyed to on-site personnel, and personnel who routinely review instrumentation data, concerning, ill the most likely failure modes 12) how the monitoring efforts relate to these faifura modes, arm 13) what constitutes unexpected performance that requires prompt investigation. 16 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 169 of 230 ED 002061 00172725-00169 Go to Table of Contents Guidelines for Cooperation with the Alaska Dam Safety Program Appendix G Alaska Dam Safety Program Visual Inspection Checklist Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 170 of 230 ED 002061 00172725-00170 Go to Table of Contents ALASKA DAM SAFETY PROGRAM VISUAL INSPECTION CHECKLIST NID !D#__ SHEET OF G E N E R A L IN FO RM ATIO N NAME OF DAM: NATIONAL INVENTORY OF DAMS !D#: OWNER: HAZARD POTENTIAL CLASSIFICATION: SIZE CLASSIFICATION: PURPOSE OF DAM: O & M MANUAL REVIEWED: EMERGENCY ACTION PLAN REVIEWED: POOL ELEVATION: TAILWATER ELEVATION: CURRENT WEATHER: PREVIOUS WEATHER: INSPECTED BY: INSPECTION FIRM: DATE OF INSPECTION: ITEM RESERVOIR 1. Any upstream development? 2. Any upstream impoundments? 3. Shoreline slide potential? 4. Significant sedimentation? 5. Any trash boom? 6. Any ice boom? 7. Operating procedure changes? YES NO REMARKS DOWNSTREAM CHANNEL 1. Channel a. Eroding or Backcutting b. Sloughing? c. Obstructions? 2. Downstream Floodplain a. Occupied housing? b. Roads or bridges? c. Businesses, mining, utilities? d. Recreation Area? e. Rural land? f. New development? EMERGENCY ACTION PLAN 1. Class I or Class II Dam? 2. Emergency Action Plan Available? 3. Emergency Action Plan current? 4. Recent emergency action pian exercise? DATE: INSTRUMENTATION 1, Are there a. Piezometers? b. Weirs? c. Observation weiis? d. Settlement Monuments? e. Horizontal Alignment Monuments? f. Thermistors? 2. Are readings a. Available? b. Piotted? c. Taken periodicaily? Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 171 of 230 ED 002061 00172725-00171 Go to Table of Contents \ ALASKA DAM SAFETY PROGRAM VISUAL INSPECTION CHECKLIST NiD ID#_______ SHEET OF SAFETY ITEM SAFETY 1. ACCESS a. Road access? b. Trail access? c. Boat access? d. Air access? e. Access safe? f. Security gates and fences? g- Restricted access signs? 2. PERSONNEL SAFETY a. Safe access to maintenance and operation areas? b. Necessary handrails and ladders available? C. Ail ladders and handrails in safe condition? d. Life rings or poles available? e. Limited access and warning signs in place? f. Safe walking surfaces? 3. DAM EMERGENCY WARNING DEVICES a. Emergency Action Plan required? b. Emergency warning devices required by EAR? c. Emergency warning devices available? d. Emergency warning devices operable? e. Emergency warning devices tested? f. Emergency warning devices tested by owner? g- Emergency procedures available at dam? h. Dam operating staff familiar with EAR? 4. OPERATION AND MAINTENANCE MANUAL a. O & M Manual reviewed? b. O & M Manual current? c. Contains routine inspection schedule? c. Contains routine inspection checklist? YES NO REMARKS TYPE: TYPE(S): WHEN: DATE: Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 172 of 230 ED 002061 00172725-00172 Go to Table of Contents ALASKA DAM SAFETY PROGRAM VISUAL INSPECTION CHECKLIST NiD ID#_______ SHEET OF EMBANKMENT DAMS ITEM EMBANKMENT DAMS 1. CREST a. Any settlement? b. Any misalignment? c. Any cracking? d. Adequate freeboard? 2. UPSTREAM SLOPE a. Adequate slope protection? b. Any erosion or beaching? c. Trees or brush growing on slope? d. Deteriorating slope protection? e. Visual settlement? f. Any sinkholes? 3. DOWNSTREAM SLOPE a. Adequate slope protection? b. Any erosion? c. Trees or brush growing on slope? d. Animal burrows? e. Sinkholes? f. Visual settlement? g. Surface seepage? h. Toe drains dry? i. Relief wells flowing? j. Slides or slumps? 4. ABUTMENT CONTACTS a. Any erosion? b. Seepage present? c. Boils or springs downstream? 5. FOUNDATION a. If dam is founded on permafrost (1) Is fill frozen? (2) Are internal temperatures monitored? b. If dam is founded on bedrock (1 ) Is bedrock adversely bedded? (2) Does rock contain gypsum? (3) Weak strength beds? c. If dam founded on overburden (1) Pipeable? (2) Compressive? (3) Low shear strength? YES NO REMARKS TYPE: TYPE: TYPE: TYPE: TYPE: Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 173 of 230 ED 002061 00172725-00173 Go to Table of Contents ALASKA DAM SAFETY PROGRAM VISUAL INSPECTION CHECKLIST N!D ID# SHEET TIMBER DAMS ITEM TIMBER DAMS 1. CREST a. Any settlement? b. Any misalignment? c. Adequate freeboard? d. Deck timbers sound? 2. ABUTMENT AND FOUNDATION CONTACTS a. Any erosion? b. Seepage present? C. Boils or springs downstream? d. Exposed bedrock? e. is bedrock deteriorating? f. Visible displacements? 3. STRUCTURAL AND CRIB TIMBERS a. Any deterioration? b. Are ends broomed or checked? c. Are timbers preservation treated? d. Are timbers pinned or boited? 4. CRIBS a. Are cribs filled with rock fill? b. Is rock fill sound rock? YES NO REMARKS TYPE: TYPE: Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 174 of 230 ED 002061 00172725-00174 Go to Table of Contents ALASKA DAM SAFETY PROGRAM VISUAL INSPECTION CHECKLIST NiD ID#_______ SHEET OF ITEM SPILLWAYS 1. CREST a. Any settlement? b. Any misalignment? c. Any cracking? d. Any deterioration? e: Exposed reinforcement? f. Erosion? g. Silt deposits upstream? 2. CONTROL STRUCTURES a. Mechanical equipment operable? b. Are gates maintained? c. Will fiashboards trip automatically? d. Are stanchions trippable? e. Are gates remotely controlled? 3. CHUTE a. Any cracking? b. Any deterioration? c. Erosion? d. Seepage at lines or joints? 4. ENERGY DISSIPATERS a. Any deterioration? b. Erosion? c. Exposed reinforcement? 5. METAL APPURTENANCES a. Corrosion? b. Breakage? c. Secure anchorages? 6. EMERGENCY SPILLWAY a. Adequate grass cover? b. Clear approach channel? c. Erodible downstream channel? d. Erodible fuse plug? e. Stable side slopes? f. Beaver dams present? SPILLWAYS YES NO REMARKS TYPE(S): TYPE(S): Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 175 of 230 ED 002061 00172725-00175 Go to Table of Contents ALASKA DAM SAFETY PROGRAM VISUAL INSPECTION CHECKLIST N!D ID#_______ SHEET OF LOW LEVEL OUTLET ITEM LOW LEVEL OUTLET 1. GATES a. Mechanical equipment operable? b. Are gates remotely operated? c. Are gates maintained? 2. CONCRETE CONDUITS a. Any cracking? b. Any deterioration? c. Erosion? d. Exposed reinforcement? e. Are joints displayed? f. Are joints leaking? 3. METAL CONDUITS a. Is metal corroded? b. Is conduit cracked? c. Are joints displaced? d. Are joints leaking? 4. ENERGY DISSIPATERS a. Any deterioration? b. Exposed reinforcement? 5. METAL APPURTENANCES a. Corrosion? b. Breakage? c. Secure anchorages? YES NO REMARKS TYPE Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 176 of 230 ED 002061 00172725-00176 Go to Table of Contents ALASKA DAM SAFETY PROGRAM VISUAL INSPECTION CHECKLIST N!D ID#_______ SHEET OF ITEM INTAKES 1. EQUIPMENT a. Trash racks b. Trash rake? c. Mechanical equipment operable? d. Intake gates? e. Are racks and gates operable? f. Are gate operators operable? 2. CONCRETE SURFACES a. Any cracking? b. Any deterioration? c. Erosion? d. Exposed reinforcement? e. Are joints displaced? f. Are joints leaking? 3. CONCRETE CONDUITS a. Any cracking? b. Any deterioration? c. Erosion? d. Exposed reinforcement? e. Are joints displaced? f. Are joints leaking? 4. METAL CONDUITS a. Is metal corroded? b. Is conduit damaged? c. Are joints displaced? d. Are joints leaking? 5. METAL APPURTENANCES a. Corrosion? b. Breakage? c. Secure anchorages? 6. PENSTOCKS a. Material deterioration? b. Joints leaking? c. Supports adequate? d. Anchor blocks stable? INTAKES YES NO REMARKS TYPE MATERIAL: Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 177 of 230 ED 002061 00172725-00177 Go to Table of Contents ALASKA DAM SAFETY PROGRAM VISUAL INSPECTION CHECKLIST N!D ID#_______ SHEET OF CONCRETE DAMS ITEM CONCRETE DAMS 1. CREST a. Any settlement? b. Any misalignment? C. Any cracking? d. Any deterioration? e. Exposed reinforcement? d. Adequate freeboard? 2. UPSTREAM FACE a. Spalling? b. Cracking? C. Erosion? d. Deterioration? e. Exposed reinforcement? f. Displacement? g- Loss of joint fillers? b. Damage to membranes? i. Silt deposits upstream? 3. DOWNSTREAM FACE a. Spalling? b. Cracking? C. Erosion? d. Deterioration? e. Exposed reinforcement? f. inspection gallery? g- Foundation drains? b. Foundation drains clear and flowing? i. Seepage from joints? j- Seepage from lift lines? 4. ABUTMENT & FOUNDATION CONTACTS a. Exposed bedrock? b. Erosion? C. Visible displacement? d. Seepage from contact? e. Boils or springs downstream? YES NO REMARKS TYPE OF DAM: TYPE: Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 178 of 230 ED 002061 00172725-00178 Go to Table of Contents Guidelines for Cooperation with the - Alaska Dam Safety Program Appendix H Reporting the Performance of Dams Excerpts from Guidelines fo r Reporting the Perform ance o f Dams, by the National Performance of Dams Program, Stanford University, 1994, H-l Guidance for Determining Whether a Dam Incident Has Occurred H-2 Dam Incident Notification Form H-3 Hydrologic Incident Reporting Guidance H-4 Seismic Incident Reporting Guidance Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 179 of 230 ED 002061 00172725-00179 Go to Table of Contents Guidelines for Cooperation . with the - e Alaska Dam Safety Program Appendix H-1 Guidance for Determining Whether a Dam Incident Has Occurred Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 180 of 230 ED 002061 00172725-00180 Go to Table of Contents Reporting Basics--Hew to Rpou the Performance of Darns Table 3-- uldanee for Determining If a Dam Incident H a s Occurred | Inspection Findings | T h e findings o f a darn safety inspection that Id entifies a ptevioBsly niaeporied (to the C en ter) Incident o f sa tisfa cto ry or unsafe conditions at a dam (e x e te iv e o f ordinary m aintenance and repair and findings o f taadafeiaeies relativ e to current design criteria.) | D am age, Signs o f D w t-o v Instability O bservation o f dam age, tges o f distress o r instability o f the- d am o r a p p ia te a a a t strn cM re s . D am B re a ch , B a m Failure Darn breach (partial, o r com plote) C ontrolled B reach Planned in o n -m ierren cy , co n ncideut initiaied ) broach ; o f she dan ife v -ih U c r * 1d <ut to re m -'x a th e d a m f r a | iu ''Ctvis.c oi to r e w e p a r w pas D r w rtttream R elease-- C ootfolJed or U ncontrolled Des. r t t o l k 'd ryk-ass M d tc re s e rv o ir {e ,g ,, a p p s r te s a n r j wru< n a c m o'pri . c :s n t m u u n ro lled r e le a s e w ith dam age. ( )m low Mood B arthq u a fe s ITiC p erform an ce o f a dam {s;U isiavi.:y or ansausfactery. anticipated or unanticipated generated .i b y a new by s e ism ic e v e n t os in flo w flo o d M feoperatibn, O perator hJXC M isaperanon o f appurtenant sm teta res sods: as during: a hydrologic event. E qaifm jeot Failure Failu re o f ineeh& nkai or electrical equipm ent to perform the dam safety rum nions fo r w h ich thev were iv.k ; i D eterioration D e te rio ra tio n at c o n c r e te ,.s te e l o r r i m b e r ,stru ctu res that, j jeopardise?, d r stro cio ra l/iu n etio ta ! integrity o f th dam j or appurtenant tfao nreG ( Darts Safety M o d ifica tio n M o d ificatio n s to im prove-the safety o f the darn or t ap p arten ant stru ctu res s a c k as m igh t be req u ired due. to j ch an g es in fe e design: order.. N ote: R ep airs fo llo w in g J an incident arc reported as part o f a follow -tip rep art I Ifeserv ah Incidents i E v e n ts f e a io c e o r in d ie re se rv o ir f'c ,g ,, la n d slid e s, 1 i w aves) feat m ay im p t fee safety o f'fee dam , 1 E m ergency A ction Plans Im plem entation o f th e E m ergen cy A ctio n Piatt f or | e m e rg e n c y a c tio n s) in- p ari o r -w hole. | Begniatory A ctiou m 'fis c re g u la to r h a s d eterm in ed unsafe: c o n d itio n e x is ts , | o r fee data does nos m eet applicable design criteria (e ,g ., j inadquate spillw ay capacity), and requires action to be ta k e n by fe e o w n e r (e,g<> re s e rv o ir r e s tr ic tio n , sa fety m odification.) { - Consultthe GmMinm Referencefor specific wpeirtwg catena Sierra Club v. EPA 18cv3472 NDCA Q Tier 10 Attachment F Page 181 of 230 ED 002061 00172725-00181 Go to Table of Contents V; ' - Guidelines for Cooperation with the Alaska Dam Safety Program Appendix H-2 Dam Incident Notification Form Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 182 of 230 ED 002061 00172725-00182 Go to Table of Contents Section 8-----D.sc;dptn otti Dam incident Repo Dam incident Notification NATDAM;D: Stats Dam Name' Note: Fmarawho&ufteras intm ing multiple dam . subm cm DIN r sch dam orattach a m TDAMiisi ofhdam s r "X in c id e n t idiFVCK'ny Incident Datsis):___ J Flood U Seismic Event Deterioration .J Seepags/Piping Remarks'* , ,, Dam Operations di ModDratior/Mepair sj Heswior Ine dent Older ..................... L <"/ ; S\. nr. ft j; y\ Dsm /Apputim m Structure Breach r..i. Reserwor Status8, wmim&m/dpsfFmm J Fatalities (No,) ......................... J infimes {No 5 ................. J Prooertv Damage N" Damage Remarks-. P repared B y Telephone: ( I Hama:............................................................. Fax: (___ } Organization: ....... .................................. ...... Address: ................................... .......................... Date K<.c'd::: rnm i Mats SmUf Tkm L im Dare Rev'd: Rov'd By; _ 'Timspacecm be usata desurfm mecheckedtuxes Addtoonsipagesom imim a as rmmmty. DIM Q i *Forexample: kmtrmtrrctwnsappose. mtpy. etc. Figure 32-- Darn Incident Notification Form Sierra Club v. EPA 18cv3472 NDCA 3-3 Tier 10 Attachment F Page 183 of 230 ED 002061 00172725-00183 Go to Table of Contents Guidelines for Cooperation with the - - - . A la sk a Dam Safety P ro gra m Appendix H-3 Hydrologic Incident Reporting Guidance Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 184 of 230 ED 002061 00172725-00184 Go to Table of Contents b e e t e n fc H y d ro lo g ic /F lo c K t E v a n t * Guidelines Reference-- Reporting Dam Incidents Seeflon 8-- Hydrologic/Fiood E ve n ts_________ ______________________________ 8 .1 introdyctlors T h i s s e c tio n p r o v id e s she R e p o r tin g Criteria a n d Requirements for in f lo w f lo o d events th a t c h a ll e n g e th e integrity of' d a m s . The R e p o r t in g C r it e r ia e s t a b lis h th e guidelines to d eterm in e w hether an in flo w flood w an ev en t o f en g in eerin g in terest. T h e R ep o rtin g R e q u ire m e n ts d e fin e the in fo rm a tio n that sh ou ld b e p ro v id ed to th o ro u g h ly raid co n sisten tly d ocu m en t in flow flood s A n in flow flo o d to a darn ta n be cau sed by heavy rain fall and /or sn o w m elt in a w a tersh ed , o r th e failure, o r larg e release fro m an u p stream d am . W h en a larg e flo o d * .'te a r s , a dam may e x p e r i e n c e its h ig h e s t r e c o r d e d p o o l le v e l a n d /o r la r g e s t f lo w th ro u g h its o u tle t sy ste m . F u rth e rm o re , it m ay b e th e o n ly tru e le s t o f a d a m 's d e s ig n . T h u s , g iv e n th e o c c u r r e n c e o f an inflow f lo r a l o f e n g in e e r in g in t e a w q sh e performance. satisfactory o r unsatisfactory, o f a d a m u n d e r th e s e c o n d it io n s s h o u ld la- d o c u m e n te d . D o c u m e n ta tio n sh o u ld in c lu d e in fo n n a h o n o n th e in llo w n<iOti at th e d a m a n d its as-bnslt stru ctu ral and h y d rau lic d m a e le n s fic s S u b sectio n -12 su m m arizes the flood ev en ts and d am age that can occur. S u b sectio n i O p r o v id e s Reporting C r it e r ia f o r f lo o d events. S u b s e c t io n 8 .4 d e s c r i b e s th e R e p o r t in g R e q u ire m e n ts to d o cu m e n t an in H ow flo o d and th e p e r fo rm a n c e o f th e d a m . S e ctio n h d escrib es th e R ep ortin g R eq u ire m en ts to d o cu m en t the p erfo rm an ce o f appurtenant sim em res A t d am s w here the op eration o f ou tlets is requ ired to provide s u f f i c i e n t o u t le t c a p a b il i t y , th e p e r f o r m a n c e o f d i m o p e r a t io n s <;o p e r a t o r s , p r o c e d u r e s ! o h n u Id b e r e p o r te d . Section 2 d e s c r ib e s th e R e p o s t in g R e q u ir e m e n t s ro d o c u m e n t d a m nporatmov S,,2 F lo o d InoW ortlS In die cum- ei a flood failure <v severe damage to a dam can occur as a result of the f o llo w in g t y p e s -I h a z a r d s * d.stn .anchor sp illw a y o v e rto p p in g , hijih flow raws in .-.ptSIwa) s and outlet works, and * h ig h p ool levels. t*rm "b a g e fim tt* is im d Sere in rviathm sense-totfcaw magnitude o fm * w tt w t m p rk m to a .tm 's amint m d storag e pariiy Sierra Club v. EPA 18cv3472 NDCA 8-1 Tier 10 Attachment F Page 185 of 230 ED 002061 00172725-00185 Go to Table of Contents | Section fre-Hydrefogtc/Ftead Each ha/ord ha* tin; potential to affect the dim in a different wav. depending on the type of dam, its design, and the rrrtgmtude of the haeard, Overtopping tan t,zu>e damage to the embankment, dans foundation, spillway, aid other appurtenant struc tures, Larue flc<ws can damage spillways! stilling basins, and outlet wml.s, ad curt cause downstream inundation. High pool-kveh can increase seepage pressure, affect structure stability r damage, unprotected areas of the upstream slope. Table 8-1 fists modes of failure and damage that can occur to the event of a large flood. 8.3 R e p o r t i n g C rite ris This subsection provides the Reporting Criteria that defsne vshen a lined incident has occurred at a darn. The criteria am based un the magnitude of the :ufkre, to the dutn, the dam outlet capacity, and the occurrence of damage to 'he dam o r .appurtenant structures. The critena include both overtopping and non overtopping events, inde pendent of whether damage or failure of the dans or its appurtenant sfoictuies occurs. Table 8-1-- M odes of Oam Failure/Dam age D ye to Hydroiogic/Flood Events (High Pool Level and/or Large Floods) Laufe o r R m k fili Dm>$ B re a c h in g fey .o v erto p p in g riu n g ' c s p ig ifiii lo irxitdccjtj stsr ecK iff, vpsira, fanng, m u teru s! drasM rc U percum (tansife'em w im A ppurtenant n u c u a e d aim ^stfaiteic r n u v e \V r sro '.-M'-xx. S ' C a r In reefe .. ap ii- p:c::xxixcx. j C tm cstin e r O ther Typus o f D s s O verturning fe e jo in afciju aJe buRrcss, tu g m e i uplift pressure S tib u rS crrk iag d s t to to } # foeodM wS or sb u tjn e m ssspixsrt i S p a in s <><? u> m ads-qi-uie t a n g , sTkiig b<iw% fouari& son supp^m Sli> W 'tx h iU \y <h?. to oxt.^-sIV: w.zp-ip? CWSfci&OO il | O iislets C m itpktem ;| S m w aare fiteumge e k e to v t a t s o a | t ot'ntU w w Buaskm | Seep ag iV p p r | Sierra Club v. EPA 18cv3472 NDCA 8 2 Tier 10 Attachment F Page 186 of 230 ED 002061 00172725-00186 Go to Table of Contents Sswirm a --Bydrstogie/Floctl Events In flow flood incid ents are categ orized in three groups, T h e follow in g are d efin ed as dam incid ents; I O v e rto p p in g Js s e n ls " any in flo w w h ich ov ertop s all <>ra p ortion o f a darn, 2. Non-tm Hopping Kw bN - A flo o d which exceeds th: 100-year event:; o t w h w h Ca 'C * th e s>pilnv<ty t> S lo w a t a d e p th o f on* h a l f m l o r g r e a t e r , r e p e t d l e w <.1 t h e S h o t ! f u r u i t r r t t w 3* Any flow that causesdamage to tire dans or spparlgnasf structures that poses a potential safety hazard. In ah eases* the performance of a dam is doeomented whether dam fatlero occurs or not Special consideration <$ given to report frydrvlogicitiood events that occur at small dams that have limited cutlet capacity (i e.. less than 100-year flood}, of which there are many, in order to limit the number of D IR s that wnuhi involve small dam s and Sow flows (t *?., much less than a 100-year event}, the Reporting Criteria for non-overioppmy flows consider only events where damage to the dam or its appurte nam structures occurs, regardless of the magnitude of the flood. F ig u r e if-1 illustrates the h y d r o k ig t c d io o d Reporting C r it e r ia . A n e v e n t i s re p o r te d i f any o f the abo v e e m a n a are m et at on e tir m ore d am s. So lite e w e o f l e c e a tr a ! p tre tp u a fso u m ca w os e * a c m e rives 1te w s (p n s stb fy d u e to a large re le a se fm ro an stpstream slam ) tnauy sins s may he ;s.let ted I'n rirr th ese C ireu tm tenees. the fo llo w in g apply; 1. The pert b im a n e c <'| a ll mm IM I s a t is f y t h e Repotting- C r it e r ia d e s c r ib e d a b o v e should b e r e r o r t e d . 2 , For e v e n ts itiv h . multiple dam un a o v e r s y s te m dial contribute to d o w n stream r e fe a s r, the p erfo rm a n ce o f a ll d am s d to u k l be rep o rted separately:. 2 Thh: m cim kw dam s w hich won' 3&n$Mui in h e m w rtep p eh fir w e n mfwd'i' L iter d a te t b e p c c ic c ic d pMftSi. m ncH ippiug (pp> # CCh ahkm $, cccrjcH c, cen t:c ric block, n ie.) ' f e r I c with #? c a e rycpcy rptliWCy c iid smetti pcirx'lprsl cpiilw ay, ih n e r H e n c e r e fe r s ic ih r in n a p m e y pchvcy. Sierra Club v. EPA 18cv3472 NDCA 8-8 Tier 10 Attachment F Page 187 of 230 ED 002061 00172725-00187 Go to Table of Contents I Sscticm 8~-~Hf<irot0gte/FfOod Evans V Figur 8~1-- flow chart for reporting hydralogln/ieecl events.: Sierra Club v. EPA 18cv3472 NDCA 8-4 Tier 10 Attachment F Page 188 of 230 ED 002061 00172725-00188 Go to Table of Contents Section 8---gdsdogic/Fiood Evente A n e x in s p ie w here th e s t w n d e m w id em u o ii eppbe.s w ou ld its 'in a c m e w h e ie a d ata Has f a tk 'd s ie tu o v e r t o p p in g a s a m o i l t o i e x t r e m e r a m i ill b ' l h c i n f l o w lit sh e dram w a x a t f e e t e d I n t h e o p e r a t io n ot i l a n x u p s tr e a m , m>. p e r f o n m m e e or th e tip -m v a m d a rn s s h o c k s b e r e p o r t e d as- w e ll, 8 , 4 Reporting ffe q u lre m e n ts T h e D S B R fo r a flo o d ev en t should inclu d e ia fd n a a tio B .o n : I She typ e and m a g n itu d e o l th e flo o d `h.tt oecnrr-'U 1 p?es spnadtsf) d o le if rise f i n d h a s g e n e ra te d In fa ir,fa b a s id 'o r s n o w r n e ih an d * th e p e r t< m ,u n c .<1 th e d a n , v lo c h iih In d ex t h e o p e r a t io n t>i d a m o u t le t s , p ,r t` rtn a n te m ,,ppnnenam v n ,*,m r-'s, and p o s i-in c d e n i u a R o s, K< iacsisN te she rep ortin g oroee-w a th e e k list and a h a u le d n u m b er o f'd a ta iun it's am p i o v s d e e *u d o c u m e n t s t lm a l u n d e n t S h e !> l f ) N fas a t im 'd north nr d ro n k h a, a sm nim sm s, mr h u v the sn u d en t ehi d G x i and su p p ortin g d een o sen tafu m fh e dat< u f o n t 's a r e p r w id e d ax n iE stn u a w s e p -iftm g f u r r w t A x o w e d m b t i J r m >, ix a n ls u p a le d .has m o d , if n ot a ll, *f th e h 'd ,d in fo im A tiu o w ill b e gessesiskxl bv th e ..n p n e e r d s . r t n g an s m e s i t p a u o n t>; t h e m o rd e n t H s r t b e i o i o r e , it ix p r e ie r a h i e th a t th e n t C R m d u d e m S o rm atio ii in n s b a sis lontn t i e , s n iid e rt n x p e tu o n rep o rts, tu-ld n o te s) F ig u re tv ? sh ow s the H y d rolog ied -in tid h n w iem tT e cfe lfst fur rt-pounsg h ito rn a tio n o n flo o d e v e n ts 'fists eh ev k h xs, w h txh is s o m p lv te i fo r e a c h d am rm o lv ed in she flo o d e v e n t, slu m id h> u se d in c o iip in e ik v s w ith d ie h i u d e n l D o ,,n ifteiU aSi>en C h e e k i n f tlr tR T K S 1 1 lik e fo llo w in g m u d e o M p e e sf sc d o en m em a lio u sh ou ld he p n o id e d * L ist am i id en h ficatio r. o f d am s a ffected by the bvdK bogre/iioo-ii ev en t * P r o je c t h y d io lo g ic /h y d u r-iln d e sig n c n le r ia ird e rsp a e n v ;atd iix -h u iit snj'm nns tion fm elod in e any m od ificatio n after x o in d n jctio n i I n f o r m a t i o n w f r e h d o c u m e n ts tt. i\ p e a n d o<xgnmde o f th e f lo o d b y d o g rap h ity p e refers to n p su eam releasi/h re-tch v s. m n ilm lA m sw u ieli g en eialed 'i * R am G II/an ew m ek event m io n ab ort, if ap p licable (see F ig . b -3) * r a p a a t y u f the d .n r to ssfeiy pass th e floocl (i,e . p o o l lev el, sto rag e, and Spill A ny flo w d ,ea5 U t e t i o p o n m d a ta , i f a p p l i c a b l e 's e e Fug. 8 - 4 ) * D o cu m o n iatio n o t d am ag e (o v erto p p in g , ero sio n , strut tu :n l, in: reused st**paic p icssu re sloe to h y d rau lic lo ad in g , e tc ) by m ean s o t h e ld n o w s, p h otos, in sp e ctio n rep orts, m ark ed -u p sca le liia w iu e s r h u v itia d istressed a tv ss an./ d im en sio n s o f d am ag e * P o st-in cid o rst a c tio n s lakers during and u h e r e v e n t by the d a m ow n er/iop eram r (in d a tlc s o p era tio n s fe q ire d and foi pci lum sexl) * E y ew itn ess reports, if available Sierra Club v. EPA 18cv3472 NDCA 8-5 Tier 10 Attachment F Page 189 of 230 ED 002061 00172725-00189 Go to Table of Contents Stetten 8--HydrotsgiteFiot Evsats Hydroiogic/FIood vent Checklist NATDAM ID: _____________ Date; Siam ID: ___ _ _ _ _ _ _ _____ Prepared By Oam Hams, _______________________ Incident D. V.... ....................................................................................................... ......... ......... _______ Flood Incident Type Bainfaii/Snowmeii Q Upstream Dam fatture Upstream Dam ! Q Otear_ _ /\/;n F eric-n -.a -cc Doto y List of Dams Affected by the Rood Event Dam Overtopping/SpBway Row fsaeOIRtetl) Reservoir Storage Data Darn Operations Reservoir Levs! Data Q Damage Report Other................ Upstream Flooding Q HydmiogiC/Hydraufic Design Repon O Design Rainta . f-tepth; and Duration Watershed Hydrologie Data Q Hydraulic Rating Corve Flood Routing Data Q Inflow Hydrograph Otear Remarks DR-m Figura S2: C hecklist for reporting hydrologie/flood events Sierra Club v. EPA 18cv3472 NDCA me Tier 10 Attachment F Page 190 of 230 ED 002061 00172725-00190 Go to Table o f Contents | Ssctton 8--Hydrologic/Fiood'Events Rainfaii/Ffood Data Summary NATDAM ID; State: __ Dam Name; D a te ;_____ Prepared By; incident ID: _ Period of Ratnfel: Location D: `t. ' to to Recorded Rainfall Amount Snow Depth (in.) Prior Hydrologic n Condition Period of Flooding: Inflow flood hydrograph Location Flood Data to to Flow Summary Amount (cf$) Figure 8-3 Ratnfa)/Flood Data Summary J D iH 4 m Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 191 of 230 ED 002061 00172725-00191 Go to Table of Contents Section 8--HydrotegtttfPfoad Events Overtopping Data Checklist N A TD A M ID; State ID. .. . Dam Name: ,, D a t e : ________ Prepared By; Incident SD: _ P e a k D epth of O v e rto p p in g (ft.) : Reservoir Elevation (ft mat) Dam Overtopping Data T im e O vertopping B e p a n _____________ Duration of Overtopping' 'Prior to breaching the Pam Upstream Flooding Depth (ft) _ Row (cfe) _ Velocity ffi/sec) Principal ................. _ _ _ _ _ _____ __ ____________ Secondary (Emergency Spillway) Depth (ft:)__________________________ blow (efs) ...... Velocity fft/sec} _ _ _ _ _ _ _ _ _ _ _ _ _ _ Remarks ..._________ _____TMTM------------------------------- --- Figure 8-4: Overtopping Data Checklist 0M i2 Sierra Club v. EPA 18cv3472 NDCA 8*8 Tier 10 Attachment F Page 192 of 230 ED 002061 00172725-00192 follow hydrographs Rservoir storage data S p illw a y - r a d a g curves (include* d a r overtopping) 0'2h Sierra Club v. E P A 18cv3472 N D C A Tier 10 Attachment F Page 193 of 230 ED 002061 00172725-00193 \o in n ?V. J3 O>*T?>>* A 3 poofeya|SofSipAn-- g Bfpss & 5` * ns "> ! s t<Xc<^&2D3 fa3'5gs3 Go to Table of Contents Section 8~-HSSflgiFtOJ givgmts r a i a f a i l ts te B o is . B t M d <> W e a t h e r .Sente. r e p o r t s n r S oil < 'o n s r r x atior* S e n w e soow r e p o r ts , snow d e p th a i a t s a r e M xnalh k n o w . O th e r in fo rm a tio n w h ich sita lrt h r u v fo la h h * c o n f o h r i s n h e y t a i m o p s smsd m e ! c o r o l o g e a l s u m m a r i e s o f t h e * t m I . A c tu a l ? u n o f f l i h e d e i m in e d by u t e r s b e d a i e , slop* a n d c o v e r . Mill typ e u n lsH n rtm n r a te s ), a n ti th e p re v io - h y d ro lu g k eoo d d m ri o f th e w are? sh ed , t.t*. w a s t h e g r o u n d w e t fr o n t p r i o r r a i n f a l l , f r o n e n . o r c o v e r n ! by v n s m . h O v e r to p p in g O a ta if th H am m - n t o p p t d d u rin g the f lo o d e v e n ! , d a ta iv ta te d to he utsse-on- o t <H ,,`t to p p m g d th e p u u > n n a t . o f t h e sla m s h o u ld b e r e p o r t e d . This should infonde t-uv hip S -4 ;- * Muomnsm dssptfe f overtopping. * S ir s g d i * ' d a ta w Sa, is x v - .u - n o f ip e r t * Tp sd da'pndik', trow vvteth s,pre,ns and d<*nrn!?em dap.* Turn, titer if t -tar >*f der sion f m flood xxhe <>\ert,ppsiig iveun * I ti( r a f io o o t e r t ir n p -n p p o m i n th e b is M e n d u if o r s , ?I >\ppls>'ank s * t *\t'i < jid t-io ( .o n d iin n i o f t in S:nr . t o r t am * J o w i . - h t ,u s k -p e * Aoh<m*' fa k e n In th e dons te n d e r p `mrt.tf a n kV fi'g n jjM r x o t t a safe A n y oth er sigtirtscdf t o b serv atio n s F ig u re 8 - 4 allo w s tt d ata form d ial ca n lie sa d to stoo araen t o v erto p p in g , 2 i> o .iim r ir is m m o l t ) a w g f G ia d fo m e v m r e p o in r ig J a m rp e s- g i v e n ut Se<rts<s M ;e-r d ,im a g e oes.rred w if. b e c le a r ly v isib le H <t ex es, le s p o n s e o f tin- e i h .r k e s ;n i ><*s s r t c f s e to t e m p o m t y fu g h p e e i - k n e b e n d e ftm m d s e e p a g e p r e s s i n e th r o u g h m i rteto n ru lrtt fon ilicsi>i asa? n o i S i e e a sily Seietted ,, n e m ,n c .u i-e Jdsssage th at sbe.*> u p as a la te r u n ' 1 h i - ty p e -i d a m ig c s h o o k : a ls o Sie reg t tie d xx he?; is d e t e e i e .i i*(> -t-itf('id i'f!t A c tio n - n s i o n e s 'f SfUtuediatcSv I ijf-'xxntg die li> d s n h ie post ev en t m s p e e t t a n - , th e d on s o r t t i c i 't i p 'i u t o j o ; e g id s s o iy a m n im ?;, h ik e ae fs` i'S fo p r e c id e So! rise - a k r x id sh e d o so : n d / n r d o w n s tr e a m a m n s R e p o r t i n g K e g n t r e f o e 'st' fo r -o r n o 'n o i '.Sieve cu rta in - m ax foss b o e s v e ; >.! in tf e .- e u i o n o n Sfesn O ps risi i s ! S e c t i o n Sei'iHM* > tu sold b e ei in s lied o lin o sep-ostsiig p o -t m a d e f o am o n a m k o t th e im p le n a i M i K n ! <tn F m e m v n e y A fo m n l i m i S5 P ii F M p R e p o rts W h e n a d d itio n 11 ifo m i r* n n a n d th e r e s u lt s o f p o s t-e v e n t in v e s t t y n o o - is h a v e been eusnol-aied, rep *ru *) jn J 'u t laser ap p rop riate d ocerrsen tation c -n e n n t: the fa llo w in g .spies .shc<ukl o s p ro v id e d : * H o o d li u o s y <?r o y d ro liig is. m v e s t s g a s u o is # j H c jiu jr s o n t h e c .sU v e <>! ' it w c , d a p o S ic a fx le Sierra Club v. EPA 18cv3472 NDCA 8-f Tier 10 Attachment F Page 194 of 230 ED 002061 00172725-00194 Go to Table of Contents Section S^Hydratogls/ftQOij Evsnst n?mm * D o e n n u 'iiia ff o n a i r e v is io n s so she d e s ig n h a s ss o f sh e d a rn or a p p ts vm scsnres. o r to o p era tin g p s o c e d u r n r m iter a s p e c t , a s a fe su li o f die ev en s. R e fe r so S u b s e c tio n 5,4- an d T a b le 3 -2 f c g sstera ! g a id a n e e d a fo llo w -s ip iR fo iim d io a that shosild b e rep orted in the P I F R . Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 195 of 230 ED 002061 00172725-00195 Go to Table of Contents Guidelines for Cooperation w i t h the - - - . Alaska Dam Safety Program Appendix H-4 Seism ic Incident Reporting Guidance Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 196 of 230 ED 002061 00172725-00196 Go to Table of Contents Seeths 9--rSstamis Events Guidelines Reference-- Reporting Oam Incidents S e c tio n i -- S e is m ic E v e n ts 01 tn fm d w c tto rs When a -cnnnc exam eats;- i d on and no pHsrteanee,i am -'iih u md to i b or penad of pnii'utuih extfesne dx stamk load*'. N e easuq s, |,o >.jsys;shtik u.fv eha. Rapes ho msegmx or al: eo.pnems n die eastsT. .crxosr -a oem ( a , 4,un, apiauKnant situmes equipment stems, rasan osr m ai To dexelog a comuieSe 4 derailed aiHk'i'i.iffiiiiij! of ilion v 'isnat p<-fina< i,, a -s np,man So p 'ter lea thuf d<vn fluents episodes h m dan s a e esposad u laxe;, of asonad rmsa-a e! es'gneefosg Internst bmdsqrukeseasi vu as 'i w l i ^ m c H n s aho aro iw c h lell and liase no ano, , v m f ssgnneaaee, )* ma:orex such m iho sagisHude * ' Idnn l ana P n e u earthquake, %h,i h peneiated high ><\ C ni es und mono ai s ninither of dams ur l aifo nsa While eaillsquakas are mes* a mmsat ns rise w iS u n C S <Wl S s fpimesnstlly ss, Cnhonisaj, lises, iss tait, ntsur flaossehoyl sise 'ounUv lis the t aurai und ensures f S sCh1.lS}e;irshqsHko^ f*<,,enriev Im m em h h o v u U '\ sumeef s V i.npeM hsrtusi. e xam haw occurred there fe p , sh>,, un se; o Nexx Mods id earthquakes ts I fb I and I h 12 han magnftias ef ? t, 9 U .iml h d; Hnthereiose, dee So Ihn ssa'isa o w,w t ifo\ig;uso in Sise C K 'S, sstong levels n i gnns'ki shaking a e Sel* ovar i m> h Lints r .egson mm ssmd4 'ave ev-refs * 'he W U T Fins si hssuaitd ssi apuse I This xeetio ps*"odxu she Reporting Crrteres ni Reifnsrements for dix un 'rising the peoormanee ni dnms during enfliqnukes !r proa le * criteria that define the size o easllujuakk of rigneeririg teestsW e n f r i a f o r u to m sfy m s* sh e d a m s sn p r u x im it y t o a n e a r t h q u a k e w h o s e p e r f o r m an ce shou ld be rep orted . and * R a p ,r e a p R e q tu 'e s rsc a 's h a : id cas-sx das.i that sh o u ld h - p r o v id e ; m d e a s , sneiss n a Ns, e o f tbs e a s t! q u a k e she h ,t / iix C at e a e h d an s a t e , m u sh e p e s io s tn isss'e oi th e sla m a-sil a p p m te n a n t Is' l*G "t the S foainssttee s n 1 ige Dassi' sC o t'til Ds psiNsshed essnldssV' fo sioptOfs! of dss!' fofous si- a snssssue exsiisS^ The I Sf S 11 T) seposl psosHle- i eorses ,edesenprsonfs rht t\ of >ais<m< haear.h andean,ap * sa*, an xciirx-t .si ,.m, and th(* foodi-e of dan; fasinse The astr ss; these Guide hue. -hould G ' asmsai vs.h dss-. doviisiieat, as well a- `ossa rasthqisaM. i'i-sseeessisp a'o>unei> >ev 7................................................. ............................................ ............... ...... ' l/ S. C m irnism m talge B u m , ''G ttim usfarfaspeatm >gBm m faH oK iiig E a isitq m ixr', Banvm Cefraa: rtaitaiS f983 Sierra Club v. EPA 18cv3472 NDCA 9,1 Tier 10 Attachment F Page 197 of 230 ED 002061 00172725-00197 Go to Table of Contents S e c tio n 9-- S eis je E v e n ts Figure 8-1 lliusdrati of the d iffe re n t in pound motion pppienesd d u ,ln 9 *s|m||ar ' * > > " u s (Reproduced from EPRI ). "> *CEUS S u b s e c t i o n 9,2 t d e m iH e * th e h a z a r d s t h a t c a n b e g e n e r a te d by a w h m i c e v e n t, S u b je c t io n 8 ,3 p ro v id es th e R e p o rtin g C r ite ria th at d e fin e th e earth.]m akes o f eog i.n e.rim g interest and the proced ure fo r id en tifyin g th e d am s R e ste d nearby w hose p erfo rm a n c e sh ou ld be rep orted S u b je c tio n 9 .3 p ro v id es the R e p o rtin g R equ irem en t! to d o c u m e n t she c h a r a c te r s s tie s o f th e e a r th q u a k e , th e p e r io r n a n c e o f easbarskm essi. .and co n cre te /tn a so n ty T-sus ap pu rtenant s tie lia s . and em e rg e n cy action*-. S u b je c tio n 9,5 i d e n t i f i e s t h e P o N o w ~ U p R e p o r t s th a t s h o u ld be r e p o rte d .. T he e n g in e e r sh o u ld n ir e to -Sectton s I f a rd Id w h ich c r - e f'a R e p o rtin g R u jtiu c n t e n ts f o r d o e tm n m tm g th e b ar.K t e n s a tw o f th e d a m b r e .x ft a n d d o w n s t r e a m f t x x h n g . and the co sts o f the dare ieJInse. tesp ectS u tb 9,2 Seismic H a za rd s ~ Descriptions Hazards that may be geperatoei by a seisraie event include: 'trous an. und motion td; the dan site, ' Swu-ii PpmrXeftiiKktMtina*, rg*gimeri$ Model ojBartkquokt Cnwnd Maxim, " K PkH P'ffH , Pi'h iw, California, Ockiber $98$ Sierra Club v. EPA 18cv3472 NDCA <b$ Tier 10 Attachment F Page 198 of 230 ED 002061 00172725-00198 Go to Table of Contents Section Seismic Evads * r e tir s e o S h e r ui t a r it movement a t or n e a r s h e d a re f o u n d a t i o n e r a t e a m a i t s , as its the sosm ,<ir. * htjuekvmirs nt dse dam k'und.iLot'-, * s e i c h e m the .reservoir, laudsItes :n the reservoir which create wave .sahn, * la n d slid e s o r ro efcia lls th at atibes tU >i,i| ay , [m w srh o tw e, o td ie i fa c ilitie s o r o th er ap p u rten an t strucruiV '., aud upstream dam failu re. I-.e h h a / a s d hot-, th e p u e n t e s ! -n s k s n -e r c t d a m m id ''p r a d e n r e s ' s t n \ l u t e s , d e o u i d n n , ou tits h / e o t d a m s a d lU - t u a im s n d e * d -c Srsaurd G a o s - a t i e m a u s d m i m -l % - c r a c k in g , n e f s ,s P in g e r o u s m re L .f k u g e , s a n t v ,, a n r e d i n y < m g ire, m r.d rn m in rs, <>i g r o u n d < t t r e i nr U n i t m o v e m e n t , or h q u e fa e ts m s r>i t i e *Grr> k a r a U r - n r s e m is a n r m e a t , A la n d s fre e >ss th e r e s m o u e.us e n ;.n e a r e a v e thaf m 'e r s .i jn 'ro d d a m a g e 1 <<r h u h a stum A Im d slsd e at h e h m o r rp rm rftvu ssi ' tra rtm e , a b o e.us e u s s e O m e n m l -w 'im nagr sir-p a ir o u tle t v a p o u r s in th e e v e n t o a n e a rth q u a k e , Uulwre o r ?te\ere dm rrege ns a d am o? its a p p u rte n a n c e s c a n o c c u r in ;s n u m b e r o i w a y s . S h o r t o f a n irn d a n ta siem ss b r e a c h o f th e d asu o r d ram atic failu re o appurtenant stru ctu res, d am age re in cip ien t failu re arc evid en t m sig n s o f visible d istress o r ch a n g es m uplift p ressu res Tabic 9 - i sum m arizes potential d a n sagre th a t c a n o c c u r is) d a m s , a p p a r te n a n t s m a m e s a n d m e e h a m c a t /c lu u t r ic a l equ ip m en t item s due to se ism ic even ts. S3 R e p o rtin g C rite ria i tiw e v e n t o l an e a rth q u a k e , .,,rif-Tsa ,u e p su v u lrd in J e t a s s u r e u tv th >-r th e p e rfo rm anee v j t e d seurhv s h o u ld tic sep ,treed P i n * h e eartnijMuke must G d s u f i i c i c n t m a im t -s d e i M ) t.* h e e>f e n g iis e e m ig s m u e s ' h a o a d , reh e-s ,.n e m l i - q m k e te rs s rs , th e , v e i ,rf g r o u n d m o t io n d e c r e a s e s i n t n r f k U u s e fu>us i-ie e p k a n e r T h e n l o r e , tv n e n d s o m e h m i t m i d m a s i c c . R i m >. w i n d s ts -..c isn e o a* a h nem os i o f C 4 r th q u ,x le n q n -s tu d e , g n >irsd srm :,or>. a n - n o in n g m o u g m r c u n g m tere.rf T h e a c r ie r m ire v o t &i$ A n u s i< c a s a i a is h s n i n s dsM arsee a r e r e a ~ e d sa u re v i i s s f a a o r s |itu lo r n a r r e a a e s d m h k tin y a s rnsuhsiU stusy p csku ssnsncc ^ U n e a ; dsfre-renere m the its , rm n so n ot a n e a d so u se m d a : W . 5 an d sia t ' R N *. k 'r s . l i s s p u h a r f f<u --as', p ast >S th e ctm otry [ h e p e r f o r m a n c e o f # f j d a m s s h o u ld b e reported th a t s o i o f y tin foil*m e R ep n ssis a Ct itrt 1. T h e ea rth q u a k e has a m ag n itu d e eq u a l to -o rg re a te r than 5 ,0 , and 1Thehuma,', , a- -v s k t 4'< %md theCBUSisAmsti asappmsiatsuefyTOPW impiiuelh. Sierra Club v. EPA 18cv3472 NDCA 8d Tier 10 Attachment F Page 199 of 230 ED 002061 00172725-00199 Go to Table o f Contents Section 3TM~Se8srsl Evenc T a ill 8 * 1 -- -D e s c rip tio n o f P o te n tia l D a m a i D u to S e is m ic E v e n ts I Harifc or RocttSi Da Comeoalo nod Qihzz Type* dfDsM Spillways O;:,- I . S - Steps Imaabllay Lk|!.teCikm/slops- iasiateijty Isskssssve sssepage vostoppteg' dise anbtofcntem uraptsateteenesr o l d e slam crest sereheor isabsitee--teAis;esl w*e iasssrasesl pats; water pressures s itiitr * !t ! ! \ iv st 1 i Qrernhemhig ofooweexa Siisf/mivyeiTifrii M iihs foaa&axion >;.:-;S;h' of esmsew watte or slabs Damage. to gates, Sjoists nr bet seefcardcal quipmM , ObSrePw j iftmajte>wbw orowl pipes Sab-tease Litiiseijrnari si >eg a ttet asa U o s i u -iepagePMtova? ofsotePte aisier at T h e d a m roust be lo c a te d within the d is ta n c e s lis te d in T a b le s 9-2 and 9-3. T h e s e ta b le s d e fin e R im ,? I w e a rth s ta k e s dust o c c u r m th e W O S a n d C E t l S . re s p e c tiv e ly . The- d is ta n c e s in T a b le s 9 - 2 an d 9 - 3 a re d e te rm in e d on th e b a sis that H it f e e - f ie ld , a v e ra g e -p e a k g ro u n d a c c e le ra tio n F G A at th e dan? stall or e q u a l e x c e e d 0 . iO g ( w h e r e g is th e c c d e r a t i o n d u e So g r a v it y , 9 8 1 .5 e m /s e r'? . Cnmm, F ig t t r e 9 - 2 t l l s s i r a i e s th e s e i s m i c R e p o r t in g ............................................ .................................................... ..................................................... [}ue t<! dittarmoea <0 tb& qoakipc ax xohmokigfc zharaci-erifiins o f the WUS and CEUS, diffenvoi ' vceOo* ah- ttw ii Uv ih'> IL$. iC o iitftfi'tii Sorvev- to yepoH the size o f .aw ncefhef.Uis.-ki. h i (ho W-/.H ortkosmEe* a w gonnm ih roponod in term* o fiik h h ? Loved Mae/dUidi, mL or iatfo.ee-wave mgnim, M<! in Et- t k fJ * ?n*<hqu{tk` magnitudes phi rtp n m d m. wm.$ &/(&& tm d^wave magnitude, am, w *X Hi, Vf" f* >*?, Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 200 of 230 ED 002061 00172725-00200 Go to Table of Contents m 9-3 T h e d is ta n c e s 'Fables 4 -2 and are used to d efin e u circu la r reg ion abou t (he earthquake e p ice n te r 11n s is sh o w n in Figu re fi ? a . T h e U S . G e o lo g ic a l Survey in G olden, C o lo iad o ca n p ro v id e the g e n p a p h te c o w iin s a te s o f the ea rth q u a k e ep icen ter shortly after it occu rs. In the W U S , earthquakes above ap p ro xim ately m agnitude 6 ,0 are often a cco m p a n ied b y an a rea m exten d ed rapture o n the cau sativ e fault. In this e a se , the en g in eer shou ld id en tify the d am s that m ay exp erien ce strong ground m otion hy d efin in g a reg ion -w h ose b o u n d a r y * a f ix e d d is t a n c e , R f r a k from a s u r f a c e p ro je c tio n o f d ie s e g m e n t o f th e fault that ruptured. T h u is sh ow n in F ig u re 9 -3 b . In m ost c a se s, ea rth q u ak es that o c c u r in th e C R U S d o n o t h a v e a rea s o f e x te n s iv e fau lt rap tu re. E x c e p tio n s in c lu d e la rg e e v e n ts su ch a s th o se w h ich c o u ld o c c u r in the N ew M a d rid s e is m ic co n e . Log (Distanc (kirn)} 5,0 Rt'mLsfi - CEU S - 26 km WUS 24 km Earthquake Magnitude F i g u r e 8 Illustration o f t h e m a g n i t u d e * d i s t a n c e during c r i t e r i a f o r r e p o r t i n g t h e p e r f o r m a n c e o f d a m s s e is m ic e v e n ts Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 201 of 230 ED 002061 00172725-00201 Go to 1able of Cohieob M Figure 9-3 Illustration of the region near an earthquake within which the performance of dams should be reported for events in the CEUS and W U S earthquakes without extended fault rupture and (to) for events above magnitude 6.0 in the W U S where ex tended fault rupture occurs.damage to a dam that affected its safety, this event and the performance of the dam should be re ported. Therefore, certain exceptions {or additional criteria) are considered. Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 202 of 230 ED 002061 00172725-00202 Go to Table of Contents S e a tio n S-- S sts m te Evssi& Exceptions T h e re may he e x c e p tio n s to the a b o v e criteria. F o r exam p le, w h ite n o t exp ected , if an e a r th q u a k e o f m a g n itu d e le ss th a n 5 0 orem sx a n d e ith e r b r e a c h e s o r c a u s e s d a m a g e So a darn or its apptidetsim s stru ctu res, sh it ev en t and the p e rlo rm a n e e o f she dam sh ou ld b e re p o ste d i o a c c o u n t f o r c if f u m s ia n c e s su c h ;tx th e s e , c e r ta in e x c e p tio n s (m addre hom d en ters' are con sid ered ? o r e a t m p ta k e * w s ih .s m .ip n ih itle 3,''.. h im G O o r Is ir d a tr * - i f x a l e o at d is t a n c e s g re a < e r f l u e R o n i .s? h o e d if. T a b l e s i( 2 a n d 9 G t h e p e r t o n o a n e e o f d a m s * h e s itd b e r e p o r te d , si esth es o f 't h e foSR >w esi; .t m d .h t w s u p u h i * a b reach o c c u r -, or \ M if fic io r t d e m a p e <<u m t h i s , ns th e o p in i o n o f th e i n s p e e f e g e n g s R e e ii p o s e s is p o te n tia l m fe t y r-m m rd so sh e d a n o r a p p s ir to n a n t s t a t c t i i r e s , i M S i n c e T a b l e s o d a n d 9 d o m l a p p ly tos e a r U '. q a d e 1- w ith 5 .0 , a vrette e l if ! tit < m n v h e d e fm e s l In th is t t ree R u n s re r e t to t h e d is t a n c e e m r e s p o n d m g to th e lo e u h u u uS th e sk im ta r th > 4 f io i r , tire curTbuimdre e p i c e n t e r that s w s b r e a c h e d n r d a r r u g e o d ui-m u th e t o t t h i m .K e h * r e ,* i1 h ii a r e x v u th M ' v G O , i lu l .u n is b rim e h sx i os d a m a g e d a n d is k x a s e d a t a d re m u c e a te n ic s turn K im # O'. irered in I'a N e q ,' o r 9 J R o n s m a s t be r e d e f in e d i n d i o e a s e R o m re d e fin e d a*- tire d is t a n c e c o r r e s p o n d s n c fe s x d arn fin h e r e t iro s n sh e e a ihqs.s<iire e p s c c s it ! th a t re a s b s e a c ir e d m d a s n a g e d F ig u r e 9 4 d h r e im s c s t h e ; te p s sn dm R e p o r t o p ( ' is e n a f< > rre s s'm ic e v e r t s Sierra Club v. EPA 18cv3472 NDCA 8*7 Tier 10 Attachment F Page 203 of 230 ED 002061 00172725-00203 Go to SeaioR 8~"Se!*mte Mmnt Table 9-2-- Distances Within W hich the Performance of Darns Should Be Reported in the Western U.S, (west of 1m t W)1 I 5. ! 34 i i: j ; $,2 ; 27 5,4 \ 30 5.8 j 33 5.8 36 6.0 34 6a 43 6.4 47 6,6 5i 6.8 55 7.0 30 7,2 >54 7.4 63 7.6 73 7.8 m 8,0 I 86 8.2 n SA..................... 99 >8.5 102 1 / 3 F i t f i n t e r n a d ia te m a $ n i i u d t s fite a p p r o p r ia te d i x t m c e t e in te r p o la te d . metnttttdpKm * T t e d is im i;e i i t e g r r t f w o t e e p ic e n te r o r f r o m i h r tm tja c e p r o t e t t o * f f the o r e - o f ru p tu re o n t h e f m l t f S e e Figs', 9~.st 4 4-56,i. Sierra Club v. EPA 18cv3472 NDCA S-8 Tier 10 Attachment F Page 204 of 230 ED 002061 00172725-00204 Go to Table of Contents S--S^issroie Events T a b l e 9-3-- D is ta n c e s W ithin W h i c h t h e P e r f o r m a n c e o f Should Be Eastern D a m s R e p o r t e d in t h e C e n t r a l a n d U.S.(eastof 105 W)1 j 5,0 5.2 5,4 5.6 5.8 5,0 6.2 6.4 6.6 6,8 7,0 1,2. 7,4 > 75 26 32 38 ! 46 ! S4 i 64 | 74 86 99 114 329 146 165 174 ! G a r mMmidiair m agnita.U -y ./->Piy.,iv t<V v< . , an bn i w r p o t a t e d . marne*. l'T h e U m e s m m i fm m the e tm k m b g epicenter. Sierra Club v. EPA 18cv3472 NDCA $S Tier 10 Attachment F Page 205 of 230 ED 002061 00172725-00205 Go to Table of Contents S e c tio n -S eism ic E v e n ts F ig u r e 9 -4 F lo w d ia g ra m : o f th e R e p o rtin g C rite ria fo r s e is m ic e v e n ts , Sierra Club v. EPA 18cv3472 NDCA 900 Tier 10 Attachment F Page 206 of 230 ED 002061 00172725-00206 Go to Table of Contents 9 ,4 R e p o rtin g R e g U ie M e n tS Smtion4--Seismic Ewnls Thre m bw cn o i. p ro v id es the R e p m tm g Ri-quiernc-nU fo i d o cu m e n tin g th e p erro rm - u m ua\ .t r e e o f d a m * d u rin g s e is m ic < * n n t T h e r e q u ir e m e n t c a p p ly m A 7 dornt * m defined by R(i> (see big. y-3y The Reporting Requirements are used to document the satisfactory and unsatisfactory performance of dams during an mfthquaKe. T h e D I D R f o r a seismic- e v e n t s h o u ld c o n t a in t h e f o l l o w i n g : 1. T ra n sm itta l S h e e t f'D l R-OOT) 2, { S e i s m i c E v e n t C h e c k l is t O T R -f.ll 3 1 3. D am S e is m ic P erfo rm an ce C h eekiest (D .IR -0 I4 J 4 , Su p p ortin g d ocu m en tation fo r each dam F i g u r e 4 - 3 s h o w s the S e i s m i c E v e n t C h e c k l is t fu n d d a ta f o r m ) . 'T h e c h e c k l i s t id e n t i t i e s th e in fo rm a tio n that sh ou ld b e p rovid ed to d o cu m en t a se ism ic e v e n t, U nibim atior! listed on the c h e c k list includes- E a r th q u a k e C tim r& e te rlsfk s - T h e lo ca tio n and .m agnitude o f th e earth q u ak e re p o rted ; O a ts P e r fo r m a n c e D a ta - The. e n g in eer sh ou ld p ro v id e a lis t o f all th e d arns that w ere in sp ected (b y state in sp ectors, dam ow n ers, e tc .) fo llo w in g the earth qu ake w hose p erfo rm an ce is bein g rep orted*' T in s list m ay h e a p rin tou t o f a p r o g r a m thar s o r te d th r o u g h a n inventory o f d a m s , a c o p y o f th e M A T - D A M file fo r ea ch d am , etc, A D ID R sh ou ld he p rovid ed fo r ea ch dam that is listed . F ig u r e 9- 6 s h o w s th e c h e c k li s t f o r reporting th e performance of a d a m d u rin g a seismic- event. T i l l s c h e c k l i s t a n d ^ u p p m im g d< cumenfutum s h o u ld h e p r o v id e d f o r e a c h d a m . T h e c h e c k lis t id e n tifie s the fo llo w in g in fo rm a tio n to be p rov id ed : * D e scrip tio n o f se ism ic S w a rd s a t th e d am site (e.g.< se ich e , fau lt d is p la c e m ent). * D o c u m e n ta tio n o f d a m a g e ("ground and stru ctu re c ra c k in g , m o v e m e n t, la n d slid e s ) to the d arn, ap p u rten an t rtmetures, an d reserv o ir rim by m ean s o f (e p h o t o s a n d / o r v id e o ta p e , a lo n g w ith th o r o u g h d e s c r ip t io n s g .. p h o t o l o g s ) * C op y o f strong m otio n record in gs obtain ed at or n ear the dam o r referen ce to a s ta te o r fe d e r a l a g e n c y w h e r e th e s e re c o r d s cars be. o b ta in e d . * Eyew itness reports (see Section 2 ). * a Vo <>l ,'> Hat m rt >rapnemd war aim pmvitsd with 4 ViK, 4 updated Im am sld fee ,">v,s,,S d in m i r e Sierra Club v. EPA 18cv3472 NDCA 9-11 Tier 10 Attachment F Page 207 of 230 ED 002061 00172725-00207 Go to Table of Contents """' S * A copy o f Use post-event lissp e e d o si repo, Irse fo d iiig fie ld n o te s a n d s k e t c h e s , i f m, a t la h i e * M ark ed -u p scale d m v in eisO . in d icatin g w here u attiege (cracking, slid es, .m ov em ents, e tc, 5 o ccu rre d , as well as the g en era l d im e n sio n s o f the d ig re s s e d area. P ost-in cid en t action s ( fe ., reserv o ir d raw -d ow n, im p le m e n ts ic n o f em er gency procedures). # A s;-bu ilt d e sig n in fo rm a tio n , in clu d in g se ism ic d esig n p u ram efers, estim ated fa cto rs o f safety (see S e ct son 2) In th e v.ise of d arn failure M e . G ev -ch * *d an > sequiu-mem* io, ie p m iu iu G ala <the b teu ch and d ow nstream m tsncunon and crisis o f the in cid en t arc giver- m S c c n o u s ) i and 12, resp ectiv ely. W h e n p rep a rin g a D ED R fo llo w in g a >'sm<e e v e n t, t< im p o r t a n t to d o c u m e n t th e d a m a g e , if any. to the d am os appurtenant tim e * arts- tn a tim e ly m an n er. T h is en su res' th at in fo rm a tio n w h ich is inim -iile a v a ila b le is not lo st o r m isin terp reSe-J. A s * B u ilt C h a r s e te n s fS c s a n d S e is m ic D e sig n P a r a m e te r s - T h e rep ort fo r ea ch dans th at e x p e r ie n c e s tire e a rth q u a k e sh o u ld in clu d e in fo r m a tio n o n th e s e is m ic d e sig n an d a s-b u ilt c h a ra c te ristic s. T h e c h e c k lis t in F ig u re 3 -5 id en tified file h aste in fo rm a tio n sh at s h o u ld b e r e p o r te d to d o c u m e n t t h e a s - b u i lt c h a r a c t e r i s t i c s o f e. d a m , 'W h e n rep ortin g a se ism ic ev en t, tin s shou ld in clu d e th e se ism ic d esig n b a sis n o g , m axim u m c r e d ib le e a r th q u a k e a n d d e s ig n m o tio n s ) and e n g in e e r in g re p o rts th at d o c u m e n t the. resu lts o f seism ic evaluation s (i.e .. estim ated fa cto r o f safety !. S tr u n g G ro u n d M o tio n R e c o r d s - In o rd er to p e n n it an u n d erstan d in g o f th eir d yn am ic resp on se, m any d ares Iw t e been m sim n u m tetj lo record the strong earth qu ake g ro u n d m o tio n at the d am sin. and th e d v n m t c re sp o n se o f th e d am its e lf T o d o cu m e n t th e eu.nhqi.M ke g ro u n d m o tio n exp es n e e d at a d e n i, the fo llo w in g in fo rm a liu n sh ou ld b e provided. A * su m m ary o f the strong m otion inxlnitnentation at the dam in ' a n y }, in d ica tin g the lo catio n o f the in stru m en iiss, inslrurnent ty p e/m o d el n u m ber, * nu m ber e l ch an n els o f d ata nd a d e' u ip ik m ot the irw fnim ent foun d ation ch a ra cte ristie v iG d r o c A , a llm m m , e tc t F ig u re F -7 sh o w s a d a ta fo rm dim t an fie u sed hs s u m m a ru e the 'h u ta e m rish c x o ' th e in stru m en ta l n>n sy s te m and th e record ed data. * A cop y (p lo t) o f the stro n g m otio n reco rd s ob tain ed from c a d i charms?) sh ou ld be rep orted . In itial rep on s m ay inclu de a cop y o f the record (u n p rocessed trace,! and estim a ted p eak v alu es. F o llo w -u p rep orts can p ro v id e th e p ro ce sse d d igital d m c history, resp on se spectrum d ata, etc. w hen they are av ailable. Sierra Club v. EPA 18cv3472 NDCA 9-1 a Tier 10 Attachment F Page 208 of 230 ED 002061 00172725-00208 Go to Table of Contents | Scatter S""~8stsroic Events Seism ic Event Checklist Earthquake Hama: Data; ______ ___ Time: Dais: ___ _ Prepared By: |EST, GST. ex ) r Earthquake C haracteristics Earthquake location; Latitude: Causative Fault; ____ Hypocentral Depth: Longitude: (miles, km) Ms - m MMi Earthquake M agm tutfef fT;<s3 ms M - M, Dam Perform ance Data * > - < > 'X- 'X Distance Range (R(m)):______ C xi* (i,e.t Table 9-2 or 9-3, other): ______________ ___________________ ______ Q list of Dams Reported Other______________________ __ Remarks_______ ------------------------------------------ -- : h lt't'i a il tftai sre known M.; srtace-mve magnffm?. Lg-wavemagnitude; mt - b o jy -nave magntorte' mt - Rfchrer tesai magnitude. M - m om ent insgteis-Je AT se<sm,c m om ent; M i ft MedSc'd M ercati intensity, (repart tiw e & e m tt m tm stty) kmmm usmits identifydamsforinspection K Ote&TS F i g u r e 9*5 S e i s m i c e v e n t checklist Sierra Club v. EPA 18cv3472 NDCA 8-0 3 Tier 10 Attachment F Page 209 of 230 ED 002061 00172725-00209 Go to Table of Contents Section 9--Seismic Events Dam S eism ic Performance C hecklist NATDAM ID: S ia te ID: _ Dam N am e: . r D a i s : _________ P re p a re d Oy In cid e n t !D: *''.V Cr/b-ro,; h\}p.?njp M S tro n g G round M otion j, G r o u n d O tts M u<r F a u t: M o v e m e n t f oundattan or Embankment Liqufaction Bessrvoir S e ic h e t>< tiwvare?ra/yvp U p stream D am Failure L and slid es O ther incident Docum entation Data Site Streng Motion Dam .'see DR-CI5/ Q L oading C ond ition s Foundation Performance Darn P e r u - ( t ie n e (C r e s t S e t t le m e n t , in s ta b ility ) O t h e r _______________________________________ -J A ppurtenant Stru cture P erform an ce (C on crete Stru ctm ee, M ech an ical and ia e tn s ai Equi p m en t i J P ost-E arth qu ake inepecdon an a D am age R eports P o st-in cid en t A ctions Operating Records? instrum entation R eco rd s R eservoir L evels pm- m<fpasteMfrquake U L eak ag e D ata O ther D enier; C cn-yr '/>.> h ry '-.n jiicn S o lis an d O th er M aterla Proporti S e ism te D esig n Evaluation R em arks om-on F ig tire S -6 C h e c k lis t fo r re p o rtin g d a m p e r f o rm a n c e d u rin g a s e is m ic e v e n t Sierra Club v. EPA 18cv3472 NDCA 9-14 Tier 10 Attachment F Page 210 of 230 ED 002061 00172725-00210 Go to Table of Contents | S e c tio n 9---S e is m ic E v e n ts --^ Strong-Motion D ata Summary CATO.AM ID: ____________ State ID: ...... Darr; N a m e ; Ea-'J libate Marne: Date: Incident ID: instrum entation ) Type; ........................................................................................... ...................... ........ Manufacturer;...................... _...................... ....................................... ....................... .... No. of Channels: Horizontal: _ _ _ _ _ Vertical: ______ Date Installed: __________ Recorded Data1 Data Form:___________________________________________________________ (scaled from plots, uacorrsotocl, processect/oorrected, etc.) Channel No. Location Direction Peak Value Units { ) \ flk addmonelpages e s rn cssm y Figure 9 - 7 Strong-motion d a t a summary f o r m om-mr Sierra Club v. EPA 18cv3472 NDCA 9-1S Tier 10 Attachment F Page 211 of 230 ED 002061 00172725-00211 Go to Table of Contents t Alternatively, * I f t h e r e sr? tu 'r tr o n g -fn o b o s i r e c o r d in g s o b t a in e d at t h e d a m t e , in f o r m a t io n tstm u a r to that d escrib ed a b o v e ! ou the n earest reco rd in g sta tio n w ith in 3 1 ksn sh o u ld be pan-Oden, in s a m e m su m ces there m ay he m u ltip le reco rd in g s within 2 0 Io n . D a ta on each station s h o u ld b e p r o v id e d . The following paraemphs d nnh specstic aspects ot ,s due *r >''pgune:wxv stnkrtnre re'jo'iisethaf u odd ;<<, doanm-nsed iot iy.vso darns louadetne s,eh. fins guidance pamllek the p*v eurthtp .A'- mspcMion guide sties published hs ISSCtAi S'*"" Embankment Pares For earth an d roefciiii dams, mj'crrnauon sh o u ld b e reported that d o e n m e r e s site following a s p e c t s o f th e dam s'e sp o u se to th e e a r t h q u a k e ; <fefonn aiH >m in the J a m a n d foursdatton dam and foan d aiion pore w ater p ressure d am ag e due to seich e ov ertop p in g fit ap p lica b le! The following summarizes die mfonoatjoa Shat should be documented In these catego ries. R e fo rm a tio n s. I th e P a m a n d P ou d a tio n - 1he loeun<m and d im e n sio n s o f d e fe r m a in m s re th e d a m a m i lo im r iu h o n s h o u ld I nr r e p o r t e d , i n c lu d in g * crest settlement, * e rrs! m o v e m e n t u psO e an t or r io w r d 'eure >ope novetnenis ft - , bulging, slumping sliding, cracking), * e f U c t s o n s l s h s . w tp s i w a !K , il a n } , an d m a r o u n d - >rN e t or t e n ir m o v e m e n t th e f o n u d a b o u If no discermHe eflm Is to lire dam or foundation have been observed, Ifns should he documented wHi, i/,S. Committee M taiy* amt, "Gttidelwm>r iHtpKtian ClwiicK 1933 * e Sierra Club v. EPA 18cv3472 NDCA Tier 10 ga&$wa*r> iMnvm Attachment F Page 212 of 230 ED 002061 00172725-00212 Go to Table of Contents Steifen |TM~S!sinte Svenfe D am w ild F o u n d a tio n H y d ra a lie E ffe cts - l i s t tniinwmf* should b e reported: o b s e r v e d c h a n g e s in se e p a g e fio-, lo c a t i o n s a n d mrbkiitv (p ro v id e m ^ a s m s - rn ens, if avai fable gp ore p ressare ch an g es ob serv ed in pie m * ? t m , occurrence o f sin k 'n o te s o r boils, o r n o discernible ch a n g es in seep a g e o r pore p re ssa re patterns- i t i 'o s r r c B M o f a S c k h e - i\m -s,,*rv>> s e ic h e a s d ire ctly <.<b M *sc.te a,k im in b N erv ed s c sk Jc x c o f a seren e w m p resen t ;tb c- the evens, Pr< foilm v m g sh o o k ! h e rep m led ' * maximum surge height of the reservoir, * dam crest overtopping data, iridudlog depth and umrer of occummas (if applicable), ami * damage mtperfeaced to the dato, appsdertatrt stsaictusss, reservoir dm, etc. Coserete sand Other Types of Dams Mayements I the Darn and Foundation - Thy localiruis arsd magnitude'' oi move ments or signs of distress m the dam and fnandahor dmyld he reported -minding, m not necessarily limited to: m ass m ovem ents up stw aio o r dow nstream * * m ass seu lem en t o f the dam , tiltin g and d ifferen tial m ovem ents, * cracking or joint openings, * ground offset o r fault m o v em en t in the lo m id a d o n , o r * n o v isible d iscern ib le effects. Bam m Fpandait Hydraulic Effeeis - The Mlowing should be reported: * tx'A crved ch a n g e s in se e p a g e flo w s an d locations (p ro v id e m easu rem en ts, if re estetici. p a re p r e s s u r e c h a r g e s o b s e r v e d us p t e a s m e f e r s , * o c c u t r e n c e o f s i n k h o l e s or b o tte , n r * n o d i s c e r n i b l e c h a n c e s 1-1 se e p irg r o r p a r e p r e s s u r e .p a tte rn s . Sierra Club v. EPA 18cv3472 NDCA -1? Tier 10 Attachment F Page 213 of 230 ED 002061 00172725-00213 Go to Fable ot Contents t A p p u r te n a n t' S t r u c t u r e s - D .em m e to c o n e jo so p o rtio n s o f sp illw a y s, tiiritke stm c m r e s . o u tie s c o n d u i t s , o u t le t c o n t r o l .s t n is ld r c s , f* o v e r p l a n t s . a n d p u m p in g s u o i m v * id e n tify an d d e s c r ib e the lo c a tio n and n a tu re o f d a m a g e {to ta l c o lla p s e , c r a c k in g , se U ie n v m t m o v e m e n t, jo in t o ffset?, ot se p a rtitio n s ), m a d e y f fa ilu r e And p nsstnk causes * ic c m o V e ffe c ts o f d am ag e o n d ie p ro ject op eratio n . * l i o s c t i l v a m e m e r g e n c y a c t i o n re q u ire d to Maintain d a rn s a f e t y o r r e s to r e n orm al op eration . D am ag e to m ech an ical and e le ctrica l equ ip m en t m d u th n g , but not lim ited to g ates, ca lv e s, p ip in g , trashraeki. m ech a n ica l eq u ip m en t (i.c ,, m o to rs, g e n e ia to n .) and su p portin g eq u ip m en t su ch as f a d tan k s, batteries, e le ctrica l su bstation s and eq u ip m en t * Identity and desert he the location and nature o l the d am ag e to th e ab o v e-listed f a c i l i t i e s , t h e n m d s r o f fa d a r e e n d titer p o s-a lb 'e c a u s e s * I d e n t i f y rife. fs o f d a m a g e o n sreytset o p e r a t io n s * D escrib e any em erg en cy actio n s requ ired to ttsam tain p ro je ct sa fe st o r restore norm al op craeons. Note: li no damage occurmd to he appartenant structures and equipment mis stisfactory performance shouid oe documentai P o s t - E a r t h q u a k e A c t i o n s - m "s l* a td \ fol lowing t h e e a r t h q u a k e o r t h e p o s t - e v e n t in sp e ctio n , trie d am o w n er m ay h,, req u ired m t a fr sig n ifica n t a c tio n s related to the safely o f the d am an d /or d ow nstream p op u lation s. T h e s e a ctio n s should b e d o cu m ented . !T e y inclu de, hut are not n ecessarily lim ited to; * d raw dow n o f the reserv oir, fp llp w -ap in sp ectio n s and m on itorin g, e m e rg e n c y r e f Airs, and * implementation of emergency procedum, if any, and th results of those proeeduaw. Sierra Club v. EPA 18cv3472 NDCA 9-18 Tier 10 Attachment F Page 214 of 230 ED 002061 00172725-00214 Go to Table of Contents 9J Follow -tip Steports Sb m 9--Satsmie Bssnte h i dre* a{<p'<<pnVo tim e w hit additional informa;; a n d th e r e s tilis o f p o s t-e v e n t i n v e s t i g l i io n s s r d / o f ts p a ir s l u t e b e e n u r e i p k 't o l , p k c re e fo r w a r d R ip o r t i s i a rtd fo r o th e r a p p ro p riate d o cu m e n ta tio n o o v c*u u i lise fe ifn v m g to rn e v * R e co m m e n d a tio n s m ade by late reg u jaio sy o t f i u J s o rd itetele: co n su lta n ts fo r follow -u p m vesligalion. * Processeci strong-moiio records, if not. available with tfee initial transmittal of Jan*.. Reports that document post-earthqnake analyses o f the darn response to the earthquake (field or labororory tests and analytical studies). * D o cu m en tatio n o f rev isio n s required to the d esig n o f the dam or appurtenant stru ctu res, o r to em erg en cy op eratin g p roced ures oj oth er a sp e cts, as a result o f the ev en t, * M o n n a tio n (renu rts, prans and sp ecificatio n s published a rticle st co n cern in g p ro je c t d a m a g e t m ir t e d m o d ific a tio n s req u ired to d ie darn am ! ap p u rici sani stru ctu re s, and (d a te d ity a ir c o s ts re su ltin g fro m die H e e ls o ! th e earthep-utre * R e p o r t s o r. lire r e s p o n s e ~u t h e d a m o r a p p u r t e n a n t s t r u c t u r e s .n s ir u m e a ta tic m (o th er than stro n g -m o rion m eo fd tn g si to the earth qu ak e Refer to Subsection 3 .4 and Table 3-2 for general guidanee on foliow-up Hifotroddott thatshould fee reportedin the DIPM. Sierra Club v. EPA 18cv3472 NDCA 9-18 Tier 10 Attachment F Page 215 of 230 ED 002061 00172725-00215 Go to Table of Contents Guidelines for Cooperation with the A laska Dam Safety Program Appendix I A Role for Risk Assessment in Dam Safety Management An excerpt from "A Role for Risk Assessm ent in Dam Safety Management/7by D.S. Bowles, L.R. Anderson, and T.F. Glover in Proceedings o f the 3rd International Conference H ydroPower '97, Trondheim , Norway, June 30 - July 2 ,1997. Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 216 of 230 ED 002061 00172725-00216 Go'to Table of Contents ofm 3rd M m m rnm S fern: TOOROKIWM XraM&eaa, NkmivfTassem ~ M y 2A W ? A m ie for ris i assassine! in data safety maaagemeat DJS. Bowles Utah W ater R esm reh I.Mb&raim% ZJlahStme Unfeerslty, IIS ,A , LJG Anderson P epE B rtm m t-& /C iv!S a m i E m im m eM d B la h S u m U ntvetsU y, U S A I F Giovor tte p m tm fit & fEcamiftks, Utah State llm m m ty, U.S.A, ABSTRAC T : In this psper we examine various Actors wlmfe lave feed to the hood for using the risk basffd approach to support dare safely decirio making Tbe teAriossiup between tins standards based and risk based approaches is reviewed. Dam safety mmagement is cast in fee context of comprehensive risk management. Trie importance of defining the dedsioa process, the role of dedskm criteria,, <redfee revolvement ofowners and sfekeholder re a "dedstOBfenvers" and staged risk assessment process is presented. The role o* risk assessment in short ratal (emergency) dam safety decisions Is tfefeussefe in addition :o kmq term decisions; on meeting extrem e events. i ffrao D iicn o N Bisk assessment is sail a. rehfevdy row rgipruarli in the field of dant safety uvrcufenm and derfeion making. When properly o'uAm~mi h cart provide valunbV rofennaho? which myy not otherwise be available ftoxu eoRventkreai approaches Quantitative examples reelude; eswatAed piatebIMes of rfem fdliHX- and the consegnerxes of failure;, and estimates of risk reduction far various srruetotfe aoc oon-strcctmm rehabilitation akemaDvew In adfefio'u fee process of arefererig a icsk assc^mexh can provide qualitative benefru such as insights into the relative sruporereee of various failure modes and ionbingr^prs and r-iftgux, and the potential value of additional analyses or field lavesrigauons liven for high banani dares, where tolerable risk confederations may lead to tin adoption of memst case" defegn (cvaluariatt) events, tire systematic risk assessment process can be useful as a oualliy assurance too! for id.e...n....t..i.f.-wy-reW* r isk reiuctioo options so the design of reliabilitaijc-a measures, project opmnrion, ox emergency action plaxxtusny AJao, fee open display of inlbanicfen obrnmod fiom a risk assessment ran he a very usdfol moons of ctryveyiag fee impMoarions of fairly techxrirnl issues to nan trermefe owners and to fee general public. Dam safety management is iTdriustcaUy a problem m risk maBagoment aad decision ttiategnmiertfficaitafety. In the pest wc feme tended m view dam safety as primarily an engmeermg problem. In many carmines enguteering standards approaches are leading to requirements for very costly medial measures at existing dams. As a resu.lt, die mriariyiag fetaidations for these stondauls ore bciug examined and ristk assessment approaches are being adopted to make explicit I Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 217 of 230 ED 002061 00172725-00217 *Go-to table of Contents tradeoffs of risks, costs, and bwefits lids le^ds os to ask the following quasttoirv. Are fee standards based and risk based approbates .mhGmpgxibte? What is driving fee rend inwards osk based approaches? How should risk assessment approaches fit into fee broad .fermewtrik of dam safety decision making m a. world in winch retaliations are becoming less prescriptive, cams me being moved from public to private icspoosihtiiiy, them is gjtywixig cijinjcribon For financial resources, and the pubic is becoming more rife averse* and wants to be moos involved in decisions which affect feeir well being" In tins paper we seek to address these questions based on fee current siate.-of-iha practice in dam safety risk assa^meut and our experience m perfonnii^ such assessment for public nuti private sector clients in fee USA and other countries, rot n feseussrun of nsk assnsstaertt procedures and several case studies the feaxu-stee reader Is directed 'to ifewles flfetl}. 2 CQhU'Z&USStVr MMKAO&MhNT RISK Art dam safety evaluation is to dam satety management, so is nak assessment to risk management. A comprehensive fecr; safety risk managentenr program should include many other components fe addition to risk assessttem for evaluating existing dam safety and alrermtive remedial actions There other compjssiuts Should include fee following; L Provision of asappmpriatriy desianeti wall tunfeteinert and reffeariy ewereised smargeney warning system and emergency action plan, 2. A comprebenrive monitoring and survetilanoe proscam wife dear assignment of tespQoribfefi for timely review and fellow- op on collected data and reports:, 3, A well trained operations and maintenance statu 4, A wfel planned, adequately faadafe and properly aenetted raaiBieaaaas program. 5, Routine indirections and periodic in- depth inspections and comprehensive riant safety reviews ana updates of any previously conducted risk assessments feat are being rdled opoaffe tiani satiny decisions. 6, Ar. effective public consultation pEQgtWEIL All of these are important interrelated cornpooems fe a comprehensive risk rasnxyement program for soy high hazard item. Hack is necessary for fee proper expose of duly of care ofthe owner and each should play a coordinated role in managing dsir: safari risks. A fempmeafery approach tc dam safety management can lead to overlooking fee implications of ufeonnation hold in other program coxpcfnente. Dams are integral structures and their safety should be managed lo a holistic mannur (Penow 1984k The on-going aspects of s. comprehensive dam safety program, such at monitoring and surveillance, should play aa jtinporant and compkntentary role to periodic comprehensive dam safety reviews. Neither fee engineering analysis tools that are used in these reviews nor fee monitor:ug and surveillance programs, provide prefectiy accurate ox complete insights fe e dam pesfonnanee (Tanelli 1992), Analysis tools are bused on idsferied represeatutreas of complex. structures anti their foundation* and must rely on estimates of materials properties and |X>stulaied loading conditions:. Murmuring and surveillance of actual performance can be mpoamn in verilyfeg the results of feeureticcl analyses. They twn also provide valuable kxfmmimm where no aaalysis tools currently oast. However, Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 218 of 230 ED_002061_00172725-00218 Go to Table o f Contents monitoring mid surveillance cannot always directly measure or observe the pammetem which are; of direct imjtofto&ee. and it takes time and expertise to make itotepretations. Analysis fools must ofim fee used as pan of the inwpretatkm. process for mcMoring data, nr for predicting the limits of acceptable behavior agairsi whack misfaetorv perSamacce isjudged. Thus ix$.an overall n--.k management program both cri-going observations and on-going analysis me imptxriam for developing confidence that a dam is. or is not, pmfocmmg, sMrfacterily. Observations and mriyses complement each other, and neither can he entirely substituted for the other. It is ntsimal pacitce to per&m comprehensive dam safety reviews approximately every five years (1COJ.D 19117), In part, the purpose of such reviews is assess the effects on cam safety of any changes in technical standards or the stete~e>f~ tho-art, if a risk based approach is adopted, the risk assessment should be updared as part o f the comprehensive review. Any changes to risk assessment inputs, such as loading conditions, fedora that would affect predicted performance of the dam, the eonseqoences uf failure, or other operational outcomes should be updated, fix this way a risk assessment becomes a "living cocimenr" which can. be used by decision makers to periodically reassess their r a p t doty of care position in fight o f ehamprtg beslness considerations, ratiriogcummimity shies, and other facto. 3 TREND TOWARD RISK. RASED APPROACH Meres in tbs potential for applying risk based, approaches xe dam mifety decision making bus accelerated m the last two ricoshes. An hicreashig number of orgntiisdons have tepm to rcruacely use risk based approaches in dam .safety evaluation. These now include the U S Bureau of Reclamatios ( V * Thun and Smart 1996), the Govemment of South Africa (Oosthuizen et at 1991), the Government of the Netherlands (CUR 1990), various Axj.siro.Handata a w and regtdators (SMEORAC 1995), and B.C, Hydxo\l99J). Many other organizations are actively considering using the risk based approach. Some factors, which have .end to the increasing use o f risk based approaches are common to dam owners and operators in different cojxrttxies. They include tire following 1. fne absence o f fimetlomd features, which are now considered to be the state-of~ tbfc-art in dam design, but which were not incorporated in many exsstmg damn (c.g. downstream Stem in embankments so dissipate pure pressure in the event o f yuiOificaat seepage). 2. I he fearer magtumde of extreme ftom case) evalualion (design) flood and earthquake events (Le. FMF and MCE, respectively), vouch ate prescribed using today's sbmdards based approaches, compared wh, those for wmek existing. dams were designed, or axe capable ofaccommodating. 3. fhc high cost of esnvering state-of-theate and extreme event "dcticiencies'". which ha&lead to questions fee jmrificatloo for the smndratis, cost effectiveness, and due diligence from a legal and overall brahmss perspective. When considering the need for remedial *orks to address staie-of-ihe-axl `'deficiencies^ under a risk based approach, the goal should be tc confidently predict that the dam will perform sMsfhctorih under a foil range of loading conditions. Satisfactory performance can. be defined using tolerable 3 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 219 of 230 ED 002061 00172725-00219 a io to Table of Contents risk enteris? suck as those summarised: m Section 6. One ofthe following few outcomes cooid result foam a risk b a te msluanon of m sx km g dam witfc state xjfrffce art andm m e m~mt ^deficiencies' L Accept the testing dam, without moeificaiiosi, If it can he demonstrated, with sufficient confidence. that the existusg dsm ess he expected to perform teirfutetilv, even though it night cot meet curretrLtermdmfa, 2. Modify the existing dam. so that the modified dam would Ire expected to perform ssilsfectoril>h with snffidert eoniitknes. but. , BOtnecessuriiy to current htedares. 3. Remove and reconsiruut the ten , so that 4 e new dam wuuld tie expected to perform sterfxctorily, w;th sufficient eoniidouee, and meet current standees 4. nccamml.wfou the dam so that it so longer poses a tteenx to dotestrearxx popvilaiiuiu at ibk. The cote end risks associated with tee drastic action of removing an existing dare and xmastxitering it would often be unacceptably large, and the resulting benefits might be questionable or dlfikuk to prove. Nevertheless, in some eases this ruay be the only way to achieve the goal of satisfactory predicted peribtmncce with m&eieixi confidence. Sadstknoiy performance under loading conditions fhar. are within the range experienced at aa existing dam, may be demonstrated ihroregh a eomlinauotx of moniioring. surveillance, and engineering analysis. for extrame floods, amthqnakcs. rntd static loading conditions, which am outside of the range that has been experienced since a dam was conflicted. die sole use ox momtoring and nnweslSacee to demonstrate salivfactory performance is problematic Howeven testing of materia: properties, structural and tebllty analyses* and the transfer o f expmlaxve from rite fardams next all be used to predict performance under extreme loading Csredjfiaus Tb" tfogxee uf confidence m performance predictions can often be improved with additional reefing, mntamnim. and analysis. Risk baser! apprresrhfes focus oxx preriicring dam performance and the confidence (or tmemaiutyl ASMxteerf with mess predictions. In contrast the sole use of traditional approaches emphaskes factors of safety and compliance with standards provides only vague k d ic te te of trie level of coufsdeo dim is being stained 'u aebies inn sadsfeemry perfotmanec Thus it is seldom clear if the level of confidence h uajusJffohly excessive or imdesmfoly small. The mregumdes of extreme walnatiot, evefflts have increased ver the past few decades for various reason* ixiclsding the following' 1, Tho <feaknowabisnm im e of worse case evens. 2, Umgfeg methodologies which te d to produce mcreasisgly more coasearvafiw design events. 3, Difficulty in dterenkhte fee pkusibibty of combinarions of contributing factors used to calculate worst case events (e.g. very small less rate coinciding with worst case ireeeiptelion to define u probable m axtetst flood event). 4.. The tendency for design profcssnmxfa to favor more eommvaive definitions of worst easeevents, 5. An Improved undecsinndma of the potential fox inadequate perfonnancu of dams and then fooudaiions under dynamic seismic loads, A danger of feesshig cam safety studios on worst case scenarios fa & ax deficiencies associated wife lower megnirade, more 4 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 220 of 230 ED 002061 00172725-00220 Go to Table of Contents ftqosxttly occumag, loading conditions. may be given too little atteatkm. Thus- by focusing on foe most unlikely fraction of one percent of the event .magnitudes, one might overlook foe range of events which arc mushmote likely to cause foilure ofan existing dam. An example would be focusmg nr. foe capability of a spillway to cope with a PMF while detiraeiKiks unde? static (water) loads arc given little M imtrmu 4 STANDARDS f: r is k b a se d ATBPvOACIIBS We use the letta. "standards based approach", to refer to the approach to design aud evaluation of dsns in which a satisfactory safety eondirfon is defined by cifom. a) compliance wife prescribed petiomwnce rneasorcs oi loading conditions; or b) use of the current suite -of-foe art (for practice), meaning fen generally accepted preseurciay approach to dam ckssgfe evaluation and eoostmetion. The tern, "risk Bused aapzoadh k A used to rater tc the apfroach to desks and evaluation of cams in which an acrsptabk safety coudirloe is dafmetl i s i y mfeoBariGn provided Ifusr a. risk assessment and oilier decision inputs, Risk assessment is a systems!c process, wherein experienced dams engineering professionals, provide decision makeiisl with estimates of foe risks and associated uncertainties of system responses, ouroames, aud consequences, which diarauterixu fee perfotmance of an existing dam and various utmedial action foremanves. under a fall range of loading coalitions It might appear that die choice between a standards based v, a risk based approach Is betwas a "dear suf' standards spproady and aifok Bascd approach which might ted to foe acceptance o f a higher risk o f falore than would, be foe case trader fee :.standards approach. However, a standards based approach is nor necessarily as deer cut as it might first appear. Tor example, under foe stpmdards based approach professional opinions and practice can vary' aver foe rctefonn of appropriate design enteria. A standards, based approach does not ensure a fours risk1' solurjor to a dam safety concern, funhennore, a standards based approach Involves "foUnd" risk tradeoffs whereas these caaeoOs con be roads more explicit tinder the risk based approach. If a. purely standards based approach is used. It is m h feeiythat the implied risk tradeoffs will be unoemrood by the decision makers, fodr technical advisors, otlter stakehoklss, and focu legal, and financial advisors In contrast, a properly conducted and wfo! communicated risk assessment caa be expected to provide all parties with valuable understanding and insights fo s these potential risk tradeoffs. In. cdforion, risk assessment can be expected to provide- a basis for priorihiring mmedial works; a dearer plume of the potential benefits of noo-structurn! m aw es, such as emergency warning systems; arui a basis for deciding on temporary operating issirictions. In some cases the ourenm s of a risk, assessment could be a decision to adopt standards based design cri>er,n. In fact the standards based approach can be thought of ax a proserfcd point on a cuariauimt o f different pertotmssce standards or design (e\ aiuatioa) leading ccmdirioss. The risk based approach can be readily used to examine a rouge of these performance rneusores or loading conditions to evaluate foe effects on telpfailtiy, coasaqiueuces, cost effectiveness, and due diligence, of devxatrog from the standards based approach. In this way the risk based approach can be used to explore the % Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 221 of 230 ED_002061_00172725-00221 Go to Table of Contents approjfomeaess of a standards based gpproadn Sole ose of a standards based approach without nsk assessment can lead to the adoption ofdesign criteria 'which naght be otjusSaby coasavarive or lav for a pascolar dam There is an importato difference between the way in which foe standards and risk based approaches treat different worst ease evatr, estimates. The standards leasedsmw&dh lends 10 treat less conservative aac more conservative sarimares of evaluation events without rra-uajiriuoa that they differ in their likelibfVKl of oommEg. to the risk based approach smaller probahilitcs of itocorreneo (annual exessdaace probabilities) cao, be associated with more conservative estimates ofextreme events. to.this way,risk assessment provides a framework within -wtxicb differences to the degree of carstrvatisni m estreme event estimated cm lx atcounted for to selecting and j.B.if>Ing aa evaiumioo event for a particular dam. Hus can be done itsme too joist probability di$tribtoiom for toe oecaim ee of various coumbtoing factors which dine an evafeatton event (e.g hfoifo xservou level and aotcisicri motoure Levels for a flood event). Il afro provides e moans for cpmtiiymg toe unemtfoarias torn errisi to dfefining worst ease oven? scenarios- Other benefits of usings a risk based approach are areseaied in Bowles (1996b) tad Bowles (19ST). 5 DEFUSING THE DECISION PROCESS In our experience it Is important to dearly define the decision process tom will be used to make g dam safety dedsioa. locally this should be done before &risk assessment to commenced so foal foe risk asscssa can lx dedgnefo in consultation with toe stakeholders, to provide Infoixoation fopjts that will be usehil at each stage in the process, end tm an agreed -upon schedule. The National Mesmxcb C om al (1996) sagas to lids type of approach m risk assessment as toedsfen driven". Adoptingstick an approach will provide a basis for impropriate m d iusri&ritle limits on the level <&nddetail ofrisk asscssmcar efforts. This is impcaiani since there is virtually no end to & amount of effort which could be pm into a detailed risk assessment- it Is toerefbm fmponsnt to remember that risk assessment sfordd. become as, end in itself; the end should foe a quality, well eomumuicated and highly defensible dam safety decision. In dearly defining toe dedsfoa process the followiag questions should he addressed: L Who are foe decision makers? 2, WlM will he the Bale for mmxmmlty coosoiiarioa and for the various stakeholders in the daeisioB- proitoSs? 3. What dedslon criteria will he used by tire decision makers? This should inclxtde an evaluation of toe emirs ftaanewoxlc to which foe then safety decision will be made mcludiag regulatory.. feg&L fitomchfo business, economic. erivimcmcnmi, sociaf m d afoci oormdtradom 4 What m.Tnroailoa from risk a sse ss ! Is needed by the decision jmakers and stakeholders through: the decision process? 6 DECISION CRTSTOA Vt'zicus criteria can be useful rojudge results from a risk isssessroeot when a long tear? dam safety decision (Bowies 11196a) & to He made (for a short term decisions sec Section 9), They induae life safety, cconoiuic arid other types of criteria. Care must he token that, the selected sritsns. am consistent with foe darn Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 222 of 230 ED_002061_00172725-00222 Go to-Iable of Contents sa fe?/ d cc'siaa fm aew atk and that they serve the dam safety dexessuij process which is Meofifrec at the outset of the risk assessment (see Section 5). A seatch tui uttexuatjonHih' spplichbk dars safety risk criteria eouidresult iu criteria which do sot serve ail dam tjwses m all eoteitries squally well. This ts particularly true Ifj as Is oilcu the case with a strict staedads approach to dccorcmodafeg catxenie events, die focus is ou sdeetiny and meetiiig a criterion, rather than. prioritiziou a sequence of risk reduction measures, giving ooststdenttion totrie cost eifsefivertess of e s c i megssxxe. Life sefeiy is always ar, important consideration. It can be evaluated using both scvieml and individual lokrahto risk enteric such as those m tbs ANCOLD (1994) CHiidewies on Risk Assessment and hy B X ~ Bydm (1997). Societal criteria art; commonly expressed as, F~N curves of emulative frequency, f . uf life loss excoxhrg *ai;ous magmlndes, N. It presides a means of ponging he scale of potential life levs train individual fhikrre modes, or combinations of failure modes for a ringie darn. Overall hfe loss can also be evaluated against an expected annual life loss criterion as m USSR (1,99?). hi either case it is sill important to evaluate mrimdmd life safety criteria to assess the potential for individuals to he excessively exposed to the ask of dam failure. Public and private im .tments sre typically evaluated against a hermitt/csst ar tale of return criterion. Darn safety pxojects seldom fair well in such evaluations because the probability of failure is often small and ffius die expected benefits are very small relative to the certain investment of capital and mtentenao.ee Hands. Dm of more than seventy dam safety risk asseAstaesas di&r we have completed only one has sh ow n a benefit/cost ratio greater than natty. Benrfit/eost ratios could be increased by adding a value for human life to the assessment of benefits However, we fed that this mis serious ethical and moral issues fed we do aot roconanend such an approach to evaluating the benefits of increased public safety. We have found that a useful approach to considering the benefits of increased public safety is to evaluate the cost effectiveness of sirxrmul and non-stoxaural alternatives. This cun be done b> ealculadag a cast-per-lifesaved tor cadi aitemsfive and comparing idese with si oil lex costs for other facilities which expose the public to risk of rife loss. By pursuing altacanves with cosLvper-ilfe saved which are leas than those In these other fields, an own is at least being consistent with the extent to whieb. these other field invest in public safety. Care must be exercised in sdecting fields m which risks are simitar in nature to those created hy dams. H ie il.S, Office ox Maiiaaemetn and Budget (OMB 1992) arguedthat rinsecost efesriveness approach is a "seasroie" way to justify hue kvestmem of federal gavetumeni dollars, or private funds as the result of regulations, to. public health and safety measures Cost effectiveness measures can also provide a very useful basis for prioritking dam safety avestjaeats such that those which are expected to result iu the greatest reductions to risk.&r a given level ofavailable fending are undertakes first. What this approach is applied to a portfolio of dans i; should maximize the rate of (public) risk reduction to which the dam own? is exposed Typkdly one can expect that such an approach to piorixuatioc will Scad to a.bigh priority being give in a dam safety program to imphxnctrstwn ot early wmitog system (EWS) la this case WSs would not necessarily be mesd m a mtostittae for 7 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 223 of 230 ED_002061_00172725-00223 Go to Table of Contents structural opium hnt as an early andtypically very cost effective step in improving public saxfety. if structural mextsmcs arc subsequently impksiaifed, an EWS might be retained as a mjpplaaaesst to stxtmul measures, In addition to toes? life safety and economic airerU, eossiderminsi should be given to financial, business, legal, id other feetors which the owner mid other stidufeolders must take into account ie their deekrfon process, This should include an ^proprime role tor community consultation in, the overall decision process so-that the dam owner meets its social rcspousibilldes as well as its business objectives and regulatory m gm xnm esits* 7 STAGED M A CH TO RISK ASSESSMENT Much o f the information needed to perform a risk assessment h commonly developed in the: course of a traditional periodic comprehensive dam safety review. However, some additional work is always rcqtnred to provide fee necessary Inputs for a risk assessment The amount of additional work depends on due scope and level o f desail of the risk msBsmtmL In convendo'iai encineedns analysis h to common practice to select urometers conservaiively. In performing fries.; analyses to provide iap'os to risk assessment ft is usually desirable to rerun these analvses using best cstSmatos ef parameters to obtain xoalxsdc performance predictions Also, it may be useful to analyze step^psrially Sake sections mfbr case of progressive failure mechanisms that would be expected to result bom foundation ifeurfavtiom for example. Li addition. sextoitivity analyses using raises of vain tor kev Vpui parameters, can provide v a te b le mfottaadon. open which to base risk assessment inputs and judgements feat experienced engineers ere expected to makeIn conducting risk assessments. We advocate using a staged approach to risk assessment Under this approach. latte moic detailed stages sue performed only if wuimntod by the potential value added to the tinm safety decision making process through reductions in the level of uncertainty in risk assessment outputs. Mom detailed stages of risk assessment usually require that more; detailed inputs be tamed Rom additssjaai field investigadoas. testing, or engineering analyses. Before proceeding with a more detailed risk assessment, the extra cost that it will entail should be- weighed against trie expected improvement in the quality of fee decision feat is to be made using risk assessment outputs, This another example oi making dam, safety risk assessment a "decision driven" activity. S OWNER AND STAKEHOLDER INVOLVEMENT We have had fe e t perfeftse with iavoWng wafer users groups, tabulators, owanrs. operators, legal achisars, n o r mana.ge.meua and politicians m fee dam safety decision process using risk assessment. So far our involvement wife immunity groups liua been mainly through our clients. However, we have found feat m most cases die nrxkmtondiEg provided by die systematic and transparent risk assessment process has r s acclaimed by all ponies, hi cur experience it has been important to involve these groups throughout the process and not just in a pfesentorion of a final report. Such a process of conxmuai mvoivemcat presents cotmnimientians challenges and one must be Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 224 of 230 ED 002061 00172725-00224 'Go to Table of Contents careful m presenting psMireinary risk assessment results to lay audiences. Credibility can be shakes if rismitlexot changes occur m these results in later stages ot the risk assessment Of course similar difficidties ran exist with a standards based sqsproack if conclusion based on preliminary aalyses axa made public and sxgaMcaatiy different conclusions are released after additional analyses am completed. The opeo and isonest communication of uncertainties is iugfcly recommended. Also it is recommended that the tccbneal risk assessment team enlist the Bvtistanee of experts in risk connuumeatson and eouanoniiy coassritnfion. Where they exist, community coasulialiou requirements contained in environmental, impact assemen processes might be used to provide for community' consultadoo in dam safety decision making. However, care should be taken to avoid diluting dare, safety issues We have repeatedly found that ii is difficult for lay people, and in many cases tadmtoai people, to have a holistic and balanced perspective on dam serty issues whan a purely standards based approach is used- The difficulty ff that tre standards approach often masks the true nature of dam safety mmregem.eat which is intrinsically a. problem in risk management and decision makmg under uncertainty. When a amadores approach is used, them is a danger uf misleading Iftc public into thinking that the adoption of standards based design (evHioffoo) criteria will provide absolut protection agamst the risk of dam failure (ire. aro risk). Fhis is obviously false sod the font that dams' that, have been built to meets standards have failed proves the point. Even though following a risk based approach presents challenges m risk crr.rnunicahou. we have found that the additional effort Is well worthwhileconsidering. the benefits of sharing a more complete ami honest picture ofthe true risks and UHcmainhes that are inejoricabiy associated with dare safety decisions. This has bees repeatedly borne out by client testimonials such as Waite (1989). 9 LONG TFBM AND SHORT TERM. DECISION'S Dan safety nsk assessments havre most comrnor.h been conducted to provide inputs to long term d isio n s nr e level nnti priority of remefisl works needed to meet extreme events, Ris*. .utsessmeo can also be Used to provide useful inputs to suck term tfocfoious, including emergens:; and the need for reset voir opemting naariettons (for example, USBR 19%) Three rime traxoes ear. Ire dinmguisna I for such decisions; 1 Prior to CimAnirtinn ofrnr.ccnal worics: 2, During construction of each phase of remedial works; and J. At the completion of each phase of remedial works. Hie outcome c f theseshod term decisions can be ased ro establish rcservob level restrictions drrrfng each phase oi remec,!! work, anti. perhips the timing oi lise weeks wife respect to vmsnnaJ rovervou ,ullu%s. At the completion of each phase of remedial works, nsk assessment ran be used to provide inputs to the decision to allow increased reservoir levels as s rasoir of the additions* margin of safety andec by those remdie! works. In long tear. decision applications of risk assessreeut the emphasis Is on balnnnxng risks, costs and benefits over a loan, period of time when -relenting as appropriate level of orotecdon against extreme avails, When using risk assessment in support of short tens decisions the concern is for the immanent 9 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 225 of 230 ED 002061 00172725-00225 Go to Table of Contents m t0pm m i o f a failure condition. In tifa ease the long term time fame cannot be counted oti f a feakadng risks, costs aad beneffa We suggest that when used m support of short term. deeisioBS, risk assessment should be used for the following 5&imary purposes; L lb identify the relative risk (likelihood and consequences) of poientiajjy m sm w m failure modes: aad 2. To reduce the risk ofeach failure mode tfarcrogha) management actions (e.g. rrsemfa oprrstisg restuctiooa, emergency repasts). b) improved detection of worsened conditions that could lead to iMhsre; c) cmmgency plumting covering all aspects of the owners raspoosibilMes. indudmg the deefaoo sad implication steps that lead to inifa.ti.og a downstream evacuada; and d) coordination of contingency planning with she local auxksriries who are responsible for evacuation. It must he stressed that the use of risk assessment m support of shortterm daeisioos must acf delay taking immediate emergency action, when suds action ri pratteo? and necessary. However, we believe tija;, oven when immediate action has been taken, risk assessment cm he used to help guide rise ongomg decision poxes. Benefits of this use of risk assessment in. this short term, context elude the fallowing: 1. Unceruanding of the devdoptttettt of event sequeones which might lead to itam sefafeiure. 2. Asjjessmeut of f a seed frit aMoaal mstunreatotwru to identify ebauged conditions, 3. Mentiilealiou. of critical values of pcrfbrntaxies parameters for miuaatxg additional mveshgaboo or emergency actio: i 4. Assessment of the benefits of various short terns actions such as reducing reservoir levels, or Improving response rimes f a mgHng emergwey retoteas 5. /Assessment o f the adequacy of warning tire and ways to increase warning time and its rebuildity. IS CONCIDSIONS We have stated that the true reiirtre o f dam safety management is faifaaally a problem hi risk mauageromt and dcebwn rakmg ussier uncertainty, is a world m which regukofats are becoming less proscriptive, dams ax being moved from public to private rsu^ousibllity, mere is growing competition for fimudal resoure-eSs and the pubic is becoming more risk averse and waste to be snore involved In decisions whtsh affect Thrir well being, the continuous fak nisiuigumcnt framewTjric can provide a valuable approach to meeting these challenges. The risk management approach should treat dams as faegfa stntcitoos whose safety should be managed in a holistic manner. ft should also take into account the ;reoattelnties Mdi uaist as a result of the current hxnitations in our capabilities io predict eud monitor dam pefanuauee. Risk assessment Is component ofthe risk: raanagernunt approach- n provides the opportunity for oTqmeering inputs to he coasxdered along side the many other factors that owners and others must consider when making dam safety decisions, In our eepenenoe it is important to deariy define the decision process that will be used. Adopting a tifmsion driven" approach to risk assessment w01provide a basis f a appropriate andjustifiable Iltmts on the level aod detail of risk esscsmrenx efforts wfa f a goal of reaching u quality, wE eomnremeutcd and highly defensible dim safety decision, 10 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 226 of 230 ED 002061 00172725-00226 *Go tollable of Contents In some situations the fends needed to meet extreme event standards simply do not roost In many other oases reliance on a porriy standards based approach does not provide adbsjiMejiastiileailan to convince lay decision makers of the need to meet these standards and a YsmlernahE has resulted. We do not argue with the desirability and even She necessity, of mating extreme event standards in marry eases. However, we observe so many cases in different countries, in which no risk reduction has been atxoiuplished even though It is well recognized that standards am not being men We suggest that in many eases ihe focus should be on identifying and jjusrifying the next most cost effective risk reduction steps father than wattmg to meet be extreme event standard. In addiriotL correcting for all state-of-the-art Dfefimeadcff is often Impmcttcahle and must be addressed by risk managament mxherTfaas structural anproadUas. The irony is illm etm. when expensive works am completed to meet standards, s tku? may to ad s nrnch mom at risk to the maifencaoning; of gate systems, to inadoqnstcly named operators, or to the absence of a properly maintained early naming system, than it was to imdercapacity of a spillway, for example. Of' course each case most be individually evaluated, and. as we lave sought to emphasise, in some cases standards based solutions will be justified When properly implemented. risk assessment can serve as a valuable tool wife a comprobeosive ilsk management fesnewmi for effective <km safety management We further suggest that such a eompx'chemfve auo spw w fic approach is necessary for the propercxerdsc ofduty of care ofa damowner and to assist m meeting due diligence. REFERENCES ANCOI.D (AiK&ftianKatkmal tYmaaitte on Large Dmas} 1994.. Guidelines to Risk Assessment.. Sydney, K w South Wales, Aostelia, Bowles, D, S, 19$?. A Comparison of Methods for Integrated Risk Assessment ofDams. & *Engineering Reliability and Risk in Water Resources", I .. Dueksteln and E. Plate (Eds,), M. Nijhoil Dordrecht, The Netherlands, pp. 147-173, B.C. Hydro 1993. Guidelines for Cnmeqii&nca-based Bam Safety Evaluations and improvements. Interim Report. Bowks, 13S i99ft. Risk Assessment in Dam Safety Decision making. In: Risk-based Decision making in Water Resources, Proceedings o f the Engineering Fmmdodan Conference, American Society o f Civil Engineers, (bite. Y. Y, Haaocs and F,, Z. Stskiv). Santa Barham, California. October. Bowles, D.S. 1993. Risk Assessment: A Tool for Dam Rehabilitation Decisions. Invited lecture is Proceedings o f Geoiechmcal Practices in Bam MehamUiution, Geotechnical Publication Bo, 55, JSC E, pp 111-130. Bowles, D.iL L.R. Anderson, and Tib (Hover 1996a. Risk Assessment Approach to Dam Safety Crimria. Proceedings oj American Society o f C m / Engineers. Geotechnical Engineering Division Specialty conference on "Uncertainty in the Geologic Environment' Prom Theory to Practice " April Bowies, D. S. 1996b, Reservu safety: A Risk Management Approach. II Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 227 of 230 ED 002061 00172725-00227 3Go toTable of Contents International Conference on Aspects o f Conflicts m Reservoir Development < M mogemmi, The City fteiverriiy, Lennon, England September, i Ip. G l i 1990, Probadiidtic Design o f flo o d D efences, Report 141, Center for Civil Eugmeering Research m d Codes, Technical Advisory Committee ou Water Defences, Gouda, The Nefedsmds 144p. FaoellL M. A. 1992 Tbe Safety of Large Dams, is: E ngineering Safety, Ed- fK Blockxy. McGraw-Hill Booh Company Europe, Mfederdhead, Berkshire. England, pp. 205*223- ICOLD 1987. Dam Safety GuMdims, Commission Imsnxaikmale des Graade Barrages, Parts, France. iSSp. Mammal Research. Council 1996, UadersamtUng Risk hfom tm g Deewmnk: in a Democratic Society. National Academy Pretax Washington, D.C. 249p MB Reducing Risks Sensibly. Fedora! Budget, OosAdrrn, C-, D. vm. der Spujs M. R. Baker, and 3. van dm Spay 1991). "Risk based Item Safety Analysis'*. Omn Engineer mg nm Perxnw. C 1994, Normal Accidents: Lm ag With High-Risk Tmknohgics, Basie Books. USA, 386p* SMKC/RAC 1995, Renew o f fieam orks, Fiaai report to the OfSce of Water Reform, Stere of Viet*a, Melbourne, Australia, Volume 1 M ain Ruport, tl8 PPUSSK 1996. Risk Assessment to Evoimm Existing Mormon Island Auxiliary Dam and Nerdfo r OpermmgMestmctmns. IIS. Bureau of Rediusatioa, Denver, Colorado. USER 199/, Cmdchnesfor AchvmgPublic Protection tn Dam Safety Dcision Making. U.S. Buren of Reckmsso* Denver, Colorado. January. Von T im , JJfe & l.D. Smart 1996. Risk Assessment Supports Dam Safety .Decisions, USCOID Newsletter, November. Waite, R.B. 1989. Dam safety cvaiuatkm for a. series, of Utah Power ami Light hydro]wer dams, including risk assessment. Owner perspectives on the Atle of the evaluation m the selection of remdiai maairares- Proceedings a j the 6th Annum conference o f the Association aj Sam Dam Safety Officiais Albuquerque, MM Sierra Club v. EPA 18cv3472 NDCA 12 Tier 10 Attachment F Page 228 of 230 ED 002061 00172725-00228 Go to Table of Contents Guidelines for Cooperation with the - - - . Alaska Dam Safety Program Appendix J Example of a Simple Decision Matrix Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 229 of 230 ED 002061 00172725-00229 at) Pastors Affecting Sarvifiblllty Z&M |s O Q Q 'w 1 to Q w Sierra Club v. EPA 18cv3472 NDCA Tier 10 Attachment F Page 230 of 230 ED 002061 00172725-00230