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No Further Action Request • . Section 4 0 Former Amen=Forest Products Facility 2/16/2006 URS Project No 17322736 Page 4-1 4.0 WELL SURVEY 6 �G In its 2001 closure request report (URS, 2001), URS presented results of a well survey, which demonstrated that there were no existing water supply wells threatened by contaminants in groundwater That survey was prepared using sources including the California Division of Water Resources, the State of California Department of Health Services— Public Water Supply Branch, and the San Joaquin County Flood Control and Water Conservation District A total of 17 water wells, excluding monitoring wells, were identified within a 1-mile radius of the site Six water wells operated by the California Water Service Company were reported within a 1-mile radius of the site All six wells were reported to be r screened deeper than 200 feet bgs, which correlates to a deeper, semi-confined aquifer, as opposed to the shallow unconfined aquifer impacted by contaminants at the site To determine which of the wells identified in the earlier survey were within 2,000 feet of the site, and also to ensure insofar as possible that all wells within that radius were identified, a new map was prepared (Figure 5) and a ground survey was conducted to supplement the existing agency data The 2,000-foot- radius survey included a door-to-door survey of businesses and residences The results of the 2,000-foot-radius well surveyare presented on Figure 5 and tabulated in Table 3 These results show five water supply wells located within 2,000 feet of the site one domestic water supply well located at a residence to the south of the site, three wells located on the San Joaquin Cemetery to the west of the site, and one well on the Stockton Rural Cemetery to the northwest of the site The direction of groundwater flow at the site has been established by over 15 years of groundwater monitoring records Historically, the direction of flow has shifted from the west-northwest in 1987 (based on data from relatively few wells), to the east in 1995, and since the late 1990s through the present has been to the north-northeast (see Figure 2) Based on that flow direction data, all five of the water supply wells identified within 2,000 feet of the site are located either up-gradient or side-gradient with respect to the site, and are, thus, unlikely to be affected by the relatively small and stable contaminant plume F%'ProiectslURS\AFP12005 DCA investigation\]IP Investigation Report\AFP 2005 Report WP-TE-Rev02 doc