FIELD DOCUMENTS_CASE 2 - Laserfiche WebLink

Home Browse Search

i til � Locations of all wells identified within the 2,000-foot radius are depicted on Figure 4. Construction details of wells located are provided in Appendix C. 4.0 INVESTIGATION FINDINGS 4.1 GROUNDWATER GRADIENT Water levels were measured in monitoring wells at the site on July 9, 1999 (Table 1). These measurements indicate that the apparent lateral hydraulic gradient of the water table is to the ` southeast at a gradient of about 0.004 feet per foot or 21 feet per mile. The potentiometric surface interpreted from these measurements is shown on Figure 3. r.. 4.2 GROUNDWATER ANALYTICAL RESULTS Analytical results for groundwater samples collected at the site on July 9, 1999 are presented on Table 2, along with the analytical results from the initial groundwater investigation for comparison. The results show that MW5-1 has no detectible concentrations ofPHCs. This is consistent with the soil samples collected at this site in 1998,which also had no detectible concentrations of PHCs, and the water sample, which showed only trace concentrations of PHCs. MW5-2, which was drilled �• adjacent to boring B5-5, had only trace concentrations of BTEX compounds(ranging from 0.001 to 0.0018 mg/1), and no detectible concentrations of TPHg or oxygenates. As with N1W5-1, the results from MW5-2 are consistent with the soil and groundwater results from boring B5-5,which showed very low and sporadic concentrations of PHCs. Similarly, MW5-3 contained only trace concentrations of toluene and xylenes (0.0005 and 0.0022 mg/l, respectively) and no detectible concentrations of other PHCs. 4.3 SUPPLY WELL SURVEY California Well Service (CWS), the purveyor of municipal water in the vicinity of the Port, was contacted on June 1, 1999 to determine whether they had any wells near the site. CWS reported (personal contact with Wayne of CWS)that they had no active wells in the area. Their water mains run in a loop along Navy and Washington Streets to supply industrial uses in the area. V The Maintenance Department of the Port was contacted to determine whether they had any wells in the area. According to the Maintenance Department, the only active well on the Port is a supply well directly north of the administration building, which is used for irrigation of lawns and other plants on the Port (driller's report included in Appendix Q. The well is located approximately 2,400 feet north of Site 5 and therefore beyond the 2,000 foot radius and up gradient of Site 5 (Figure 4). �- i&cS&dk%T$ 7 PHILIP P. Ross,R.G.