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S I i� i Chevron U.S.A. - page 7 constructed utilizing schedule 40 pve flush-thread 0.020 inch well screen. The - screened interval consisted of a 20 foot screened interval, which was roughly centered at the encountered ground water level. A No. 3 graded sand was used as a filter media around the screened interval, and completed to an equivalent depth of 2 feet above the well screen. A seal composed of bentonite pellets was place to an approximate thickness of 3 feet atop the filter media. The remaining d I annulus was backfilled with a sand/cement slurry with 3% bentonite added from the seal to the surface vault. A locking well head was installed, and a secure surface vault was placed at grade for well securit design of the y' The dg ground water monitoring wells is in general compliance with the State of California Department of Rater Resources Bulletin 74-88 (Draft) Monitoring Well Standards (DWR 153907), Well construction details have been illustrated on the Logs of Soil Borings included in Appendix A of this report. Ground water monitoring wells were developed by means of pumping. Sampling of the monitoring wells was accomplished by means of a teflon bailer. Well development water has been retained in drums at the subject� ct property Pending Proper disposal by Chevron after results of chemical analysis were complete, Auger cuttings from the drilling operation were drummed on--site. Those auger cuttiegs which did not exhibit obvious presence of contamination by field screening with a portable photoionization detector. xere segregated into "clean drums All drums were identified by sail Loring number and depths of auger cuttings specifically contained in each arum. Sampling and chemical analysis from soil borings will dictate the proper disposition of those contaminated soils b �^ Chevron. Y i DAMES &: AdnoFE