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w W The California Department of Water Resources(DWR)was contacted on July 8, 1999 to determine whether they had any driller's reports on file for supply wells within the radius of interest around the well. Ms. Anne Roth responded on July 15, 1999 with a suite of six driller's reports for wells that were located near the area of interest. These driller's reports are included in Appendix C. However,upon plotting these wells on a topographic map of the area(Figure 4),it is clear that only one of the wells is within a 2,000 foot radius of Site 5,the Nelson Ready Mix& Concrete well (#4 on map). The well is located approximately 1,000 feet south of Site 5 and is fisted as an industrial �• well drilled in 1979. It is 270 feet deep with perforations from 198 to 270 feet below ground surface and has a cement well seal from 50 feet to the surface. A driving survey of the area conducted on May 17 and June 1, 1999 indicated no other supply wells in the vicinity of the Port. bw 5.0 CONCLUSIONS AND RECOMMENDATIONS Three wells were constructed on the site to depths of about 25 feet each. The depth to water beneath the site ranged from 6.8 to 8.5 feet with a potentiometric surface gradient to the southeast at about 0.004 feet per foot. Groundwater samples taken from the wells indicated no detectible concentrations of any PHCs or oxygenates in MW5-1, the down gradient well at this site. Only trace concentrations of BTEX compounds and no detectible concentrations of TPHg or oxygenates were found in wells MW5-2 and MW5-3. These groundwater findings support the soil findings from the previous investigation, which indicated only very low residual concentrations of PHCs remain in the subsurface beneath this site. No drinking water supply wells are located within a 2,000 foot radius of the site. The only supply +r well within the 2,000 foot radius is an industrial well at Nelson Ready M'ix and Concrete, located approximately 1,000 feet south of Site 5. The well has a cement seal from 0 to 50 feet and is perforated from 198 to 270 feet. Based on the trace concentrations of PHCs detected in groundwater at this site, and the fact that i, there are no drinking water supply wells located near the site,there appears to be no risk to human health and safety as a result of the residual contaminants beneath the site. The nearest surface water body is the San Joaquin River,which is about 3,500 feet southwest of the site. The distance to the river, the very low concentrations of PHCs beneath the site, and the groundwater gradient to the southeast, would indicate that there is also no risk to the environment from these contaminants. �. 8 PHILIP P. ROSS, R.G.• �s.e��rpR