ARCHIVED REPORTS_XR0011605 - Laserfiche WebLink

Home Browse Search

The subsurface utilities identified from record search and site inspection are shown on F,. Figure 2. 4.2 Water Well Survey A survey of water wells within 1/2-mile radius of the site was conducted in September 1998, based on review of Water Well Drillers Reports on file at the California Department of Water Resources (DWR), Sacramento,California. Additionally, Banks Information Solutions (BIS), an information data base company,conducted a search of public records and well locations under contract to Alisto. The BIS Water Well Report and the additional DWR Water Well Drillers Reports are presented in Appendix I. Review of DWR files revealed the presence of seven water wells within a 1/2-mile radius of the former BP Oil site. The locations of the wells could not be determined from the information provided on the Water Well Drillers Reports. The BIS well search identified two of the seven wells included in the DWR files. Included in Appendix I is a tabular summary of the state well number,well owners, and well construction specifications of the water wells identified from the survey. The state well numbering system is based on the U.S. Land Office Survey. The well location map included in Appendix I shows the sections and letter-designated subsections used to identify the approximate location of the wells. During a field visit on May 7, 1998,an inactive water well was observed about 10 feet south of the underground fuel tanks as shown on Figure 2. The well supplied water to the service station,but was no longer used after municipal water supply was provided into the building. The well was subsequently destroyed in July 1998. On November 2, 1998, Alisto conducted a visual reconnaissance of the surrounding area for evidence of water wells such as: overhead power lines,well and pump sheds, and pressure tanks. There were no water production wells observed within a 1/2-miles radius of the site during the visual inspection,including those wells indicated from the records search at the DWR. Field notes on the visual reconnaissance are included in Appendix I. With the exception of the former onsite well, the current status of the wells identified from the record search and survey could not be verified because there were no physical indications observed during the field reconnaissance. 5.0 HYDRAULIC CONDUCTIVITY TESTING On May 7 and September 3, 1998,hydraulic conductivity testing was performed on Monitoring Wells MW-1 through MW-6 and MW-8 through MW-12. The tests were performed to calculate the average horizontal groundwater flow velocity and estimate the migration rate of the hydrocarbon release. The scope of work consisted of evacuating groundwater to the maximum extent practicable from the groundwater monitoring wells using a submersible pump, and measuring the rebound of groundwater levels within the well bore with an electronic water 7