Document 3eN70VoyO1Y33kOVgL7QeLw23

FOR SETTLEMENT PURPOSES ONLY - SUBJECT TO Rule 408, FRE Summary of Methodology - 428-Grid Surface Sediment Sampling Locations The grid cells were configured according to the approach outlined in the latest draft of Appendix B of the draft Work Plan. Once the grid cells were configured, the sample locations were placed as described in Appendix B. Specifically, Geosyntec's GIS technician used the ET Geowizards "random points in polygons" algorithm (Spatial Techniques, http://www.ian-ko.com/). We cannot obtain the code to the algorithm or software, as it is proprietary. It is a standard GIS software tool widely used by GIS practitioners, and is available from the above weblink. Note that the locations have not been moved or altered - the sample locations as shown in the figure are shown as produced by the software's randomization. It is entirely possible that some of these locations may be inaccessible due to the presence of vessels, infrastructure, or other obstacles or challenges to field team safety at the time of sampling. In those cases, a standard sediment sampling procedure will be followed to sample a location that is as close to the originally-designated location as possible, with the appropriate notifications to and/or pre-approvals from EPA. That procedure will be detailed for EPA's comment in the SAP. Sierra Club v. EPA 18cv3472 NDCA Tiers 8&9 ED 002061 00114504-00001