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LOCAL GEOLOGY AND HYDROGEOLOGY The site is located on surface soils belonging to the Stockton Adobe Clay and Honeycut Clay series They are derived from Recent alluvial fan and floodplain deposits The 40 feet of explored section consisted of clay and silt overlying interbedded lenses of silty and clayey sands below 12 feet This first sandy formation has been designated the A zone aquifer The base of the A zone is at approximately 17 - 18 feet below ground surface (bgs) An aquitard consisting of silty clay approximately 3 to 4 feet thick separates the silty clayey sand A zone aquifer from the B zone aquifer that is found at approximately 21 feet bgs and is approximately 6 to 7 feet thick In newly installed wells MW9A/B this aquitard has drastically thinned to a one foot thickness The B zone aquifer consists of cleaner moderately sorted fine to coarse sand that shows graded bedding (fine to coarse with depth) Beneath the B zone aquifer is stiff clay that extends from approximately 27 feet bgs to 40 feet bgs The original five monitor wells did not encounter groundwater in the A zone aquifer when initially drilled and sampled Depth to water measurements taken between 1993 and February 1996 indicate that the A zone aquifer was dry (depth to water greater than 17 feet bgs) MWl through MW5 are screened across both the A and B zone aquifers Sometime after February 1996 depth to groundwater measurements indicated that groundwater was in contact with the A zone aquifer, see Table I The groundwater in the vicinity of the site is semiconfined Groundwater elevation at the site varies from a wet year high of 7 feet bgs (silty clay formation above the A zone) to about 22 - 23 feet bgs (B zone) dunng the previous drought period Groundwater flow direction in the A zone at the site has generally been to the west since December 1997 The B zone shows a similar flow direction, which would be expected due to the connection between zones at wells MW 1 through MW5 3" QUARTER 2004 SITE ACTIYITILES PERMITS Proposed wells MW8A, MW8B, MMA, MW9B and MW10 were installed during this quarter Permits to install the wells were obtained from the following MW9AIB AND MWI0 San Joaquin County Environmental Health Department, permit SR90038458 MW9AIB San Joaquin County Environmental Health Department, permit SR#0038461 County of San Joaquin, Encroachment Permit CR022817 WELL INSTALLATIONS Five new wells were installed to help define the groundwater conditions of this site Two cluster wells MWS A&B and MW9 A&B along with a well installed into the gravel 4 Sanchez QM 3rd 2004