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Monitoring Well Installation Report-Tosco(Former BP)Service Station No 11192 Sel2le iber 26,2001 with 2 inch diameter, poly-vinyl chloride (PVC) well casing The bottom 20 feet of the casing consisted of 0 020-inch machine-slotted screen RMC Lonestar#3 sand was installed in the annular space, from the bottom of the boring to two feet above the top of the screened interval The wells were then sealed with bentonite followed by neat cement grount Additional-well construction details are presented on boring logs in Appendix B) The deep on-site monitonng well (MW-11) was installed within an 53 foot deep, 8 5-inch diameter steel conductor casing On August 8, 2001, Woodward installed the conductor casing inside a 15- inch diameter borehole dnlled with HSAs to 53 feet bgs The annular space between the borehole and the conductor casing was backfilled with one foot of bentonite and 51 feet of neat cement grout, placed through a tremae pipe to approximately one foot bgs This grout was allowed to cure for approximately 38 hours prior to drilling through the conductor casing On August 10, 2001, the boring for MW-11 was advanced to 79 feet bgs with 8-inch HSAs through the conductor casing MW-11 was constructed with 79 feet of 2-inch diameter PVC well casing, the bottom 10 feet consisting of 0 020-inch machine slotted well screen The well was completed with RMC Lonestar #3 sand, bentonite and neat cement placed through a tremae pipe The construction details for MW-11 are shown on the boring logs in Appendix B . 3.2 Well Monitoring, Development,and Sampling Monitoring, development, and sampling of the newly installed wells was performed by GR personnel All groundwater samples were submitted for chemical analysis under chain-of-custody documentation to Sequoia Analytical in Walnut Creek, California Copies of the well development and field monitoring data sheets are included in Appendix C Monitoring data are summanzed in r Table 1 Wells MW-8, MW-9 and MW-10 were developed and sampled on August 16, 2001 Depth to groundwater was measured and each well checked for the presence of separate-phase hydrocarbons prior to development Separate-phase hydrocarbons were not detected in any of the wells None of the wells dewatered during development However, MW-11 contained approximately 48 feet of sediment inside the well casing and could not be developed on August 16, 2001 After being properly developed, groundwater samples were collected from MW-8, MW-9 'and MW-10 in appropriate containers supplied by the laboratory On August 21, 2001, Woodward used approximately 75 gallons of fresh waster to flush the sediment out of MW-11 The sediment and water removed,from MW-11 were contained in 55- gallon drums and stored on site On August 22 2001, GR personnel developed MW-11 according the procedure detailed in Appendix A After the well was developed groundwater samples were collected and submitted for chenucal analysis as described in Paragraph 4 2 • 14024505-2 r 5 r