ARCHIVED REPORTS_QUARTERLY REPORT - THIRD QUARTER 2005

Home Browse Search

24 October 2005 AGE-NC Project No. 98-0500 Page 6 of 11 Screen was installed monitoring well MW-41 from approximately 40 feet to 60 feet bsg; in monitoring well MW-38,MW-40,MW-43,MW-46 and MW-47 from approximately 90 feet to 100 feet bsg;and in monitoring well MW-39 MW-42,MW-44,MW-45 and MW-45 from approximately 140 feet to 150 feet bsg with blank casing extended to the surface. The filter pack(No. 3 Lonestar sand)was installed surrounding the well screens additionally,a nominal bentonite pellet or chip plug was then installed above the filter pack and hydrated.The wells were then grouted to near the surface with portland cement. Water-tight, traffic-rated well boxes were then installed over the wells. As-built well diagrams are depicted on the boring logs in Appendix D. 3.4. Monitoring Well Development On 11 July through 13 July 2002, monitoring wells MW-38 through MW-48 were developed utilizing a stainless steel hand bailer and an inertia pump. Ground water was purged from each monitoring well until ground water was visually sediment free.Between 18 and 120 gallons of water were removed from the wells; however, well MW-42 and MW-46 were purged until water was generally clear of sediments. Ground water temperature, pH and conductivity were measured at regular intervals during purging using an Oakton water analyzer. Field sheets and data are included in Appendix E. Purged water was stored on-site in properly labeled, 55-gallon Department of Transportation (DOT)-approved drums. 3.5. Well Head Survey On 12 July 2005,a California state-licensed survey engineer from Baumbach&Piazza,Inc.surveyed the elevation at the top of the well casing(towc). Elevations were surveyed to the nearest 0.01-foot relative to San Joaquin County Bench Mark 83, surveyed at 17.82 feet above mean sea level (MSL).Coordinate locations(x and y)of well locations were calculated to the nearest 0.1-foot using coordinate datum NAD 83 from global positioning satellite(GPS) observations. The results of the well survey are reported in Table 1. The surveying report (Baumbach & Piazza, Inc.) is presented in Appendix E. 4.0. QUARTERLY WELL MONITORING PROCEDURES AND RESULTS The quarterly ground water monitoring event was performed on 29,30 and 31 August 2005.Ground water monitoring was performed on the renumbered monitoring wells MW-1 through MW-49, except wells MW-12,MW-15 and MW-16 were unavailable because a vehicle parked over the well or unaccessible for purging and sampling and well MW-4 and MW-29 which are sampled on an • annual basis. Advanced GeoEnvironmental,Inc.