Document VjX7aDX8vqEynxgoj5MxwXr6g

AR226-2589 BEWSHTOCLOEPDYOACVUAMILEANBTLE .'Sf'.ja*' !< m O H oe PO HHUoe*1 UPOl -oeJ NtnJ DuPont Washington Works | | | | :,J ; Meeting with ACOE and EPA July 18,2002 ,<Nv\.V S. ; 'yi -iV.-c j'- EID781126 N<Jr CD w ASH027847 S iS S l Bedrock - - Permian Dimkard Group - Shales, sandstones, siltstones, minor limestones,, e p a l;:^ Alluvium - Pleistocene glacial outwash deposits p f v* coarse sands and gravels ;^ y . ; ?, predominant valley fill sedim ents Ievels 111^ river ^lley cedm the center of the ri iilfIggradation events ||d i:^ |^ ^ n n 4 e r upper terraces 3 'Ti\L, -..--j . f ilM&i?-. v; Alluvium (cont.) -- Holocene Ohio River overbank deposits - silts, clays, fine sands low er terraces in river valley thick (20 to 25 ft) deposits on low er terraces .. f ?. _ '* thin mantle on upper terraces *. low er 2 H olocene terraces now covered by Ohio R iver due to d a n p iu ig |'? l5 f.f| iK-Jr..fi .^.5s,aKN5- iffVKoPiri- EXD781128 sao wHo<031o*0}, tCoO i?iSPSFf- EID781129 Idealized Ohio River A SH 027B 50 EID78X130 EID781130 7 ASH027851 EID781132 XO mH -OOsOl|i' frO Alluvial Aquifer: - Primary groundwater source - Coarse sands and gravels (Pleistocene sediments) - Typically 100 to 300 ft/d - Mostly unconfined - Locally confined by Holocene overbank deposits aquifer minor,iineston.es (Dunkaxd Group) plant site and Local Landfill 8 9 E ID 781133 EXD781134 S3 w H o s*o4 CUDT . : r iteS#*3 EPA / ACOE Coiglg Modeled Stage o f Ohio River - Previous model above normal pool elevation - Revised to normal pool elevation (582 ft, above MSL) Recharge Rates - Previous model -11 in,/yr. across domain - Revised nation based on surficial sediment distribution Rates lio d el - rates were estimated and adjusted during calibration .e^ered bpurly or daily pum ping rates from the D uPont, L ittle H ocking, Spnfatect for GE (no data available) 10 UUrHH-) GmO W in ASH027855 1-i** i EPA / ACOE C o W il Boundary Conditions - Previous model - north edge of domain endB: - Revised: * No-flow boundaries coincide with bedrock divides Ohio Riverbed Conductance Previous model - conductance based on very low K o f riverbed l^.Con^uctance based on riverbed K ~10% ofexpected Kv of underlying alluvial 11 A i.- EID78136 <mH fONfi UmGDl Primary Data Sources RFI Report, DuPont, 1999 - lithologic data - groundwater elevation data - aquifer testing data /-' -SvII- Simard, 1989, Geologic History of the Lower Terraces a n J f || Upper Ohio River Valley, West Virginia Geological Survey O I"-- Lithology, thickness, and depositional history o f the Ohio River alluvial sediments - Historical low water levels of the Ohio River gjgpjipzar and Mathes, 2001, Aquifer-Characteristics Data for West Virginia, U S (S ^ 2 | ir^Resowces Investigations Report 01-4036 glJi^draulc conductivity data sejrv ** targe-rates KiSL-ft,.:.. . ^ g f^ r.S u p p ly Investigation Reports i, 1986 ..... hy 12 'AJ- -*V: :^-r C" Ohio River Bathymetric Maps, ACOE, A A A r|p Pumping Rate Data A A g - Hourly or daily rates from DuPont, L ittle H ocking,L u - Individual w ell rates- in most cases Well Logs - Little H ocking - GE A Shell EID781137 KaoJ MH<031C<D1T <jd Isle., Little H ocking, Shell 13 EID78113S mH 3O^PGO3O LCOn Groim dwtefM l* Model Domain -- 12,700m E-W by 8,045m N~S (41,568 ft. by 2 6 # 4 3 f -- 153 rows x 235 columns x 3 layers -- 107,865 cells (69,705 active cells) -- Grid spacing: 25m to 100m (82 ft. to 328 ft.) Boundary Conditions pjlebharge sources River lurfece water features .public water supply w ells features on bedrock areas 14 ASH027859 EID781139 EID781139 E1D781140 17 E ID 781141 1ID781142 19 EID781143 c EID781144 Synoptic ASH27865 EID781145 EID7B1145 EID781146 23 EID78147 ASH027868 E ID 781148 EID781148 ASH027869 EID781149 EID781149