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Geological recknics Inc. Page 3 Well Installation and Quarterly Groundwater Monitoring Report Project No. 1030.2 June 18,2002 ' • Measured depth to water, purged wells and collected groundwater samples for laboratory analysis. • GPS Survey of all monitoring wells and domestic well as required under AB2886. 1 2.0 MONITORING WELL INSTALLATION 2.1 Monitoring Well Installation In April of 2002, Geological Technics Inc. supervised the installation of a groundwater monitoring well in a conductor casing. The well was installed in the vicinity of the former gasoline UST (Figure 2) to determine if gasoline range petroleum hydrocarbons are present in the groundwater below an aquitard encountered at approximately 19 feet bgs. Monitoring wellpen-nits were secured from the San Joaquin County Public Health Services/Environmental Health Department (SJC PHS/EHD). The local regulatory agency was notified 48 hours prior to commencing work. The subsurface was cleared of underground utilities by notifying Underground Service Alert. MOn April 12, 2002, a conductor casing was installed to a depth of 19.5 feet bgs. A 15-inch outside diameter (o.d.), hollow stem auger rig owned and operated by V&W Drilling (C57# ' 720904), was used for the installation of the conductor casing. The conductor casing has an 8.25" inside diameter and was set in a clay layer encountered at 19 feet bgs. The annular space around the casing was backfilled to a depth of 8 feet bgs. The annular space was then grouted to grade. On April 25, 2002, the monitoring well was installed to a depth of 34.5 feet bgs using an 8- inch outside diameter (o.d.), hollow stem auger drill rig owned and operated by V&W Drilling (C57# 720904). The monitoring well was constructed using 2.0-inch diameter schedule 40 PVC casing with flush threads. The details of construction are listed in the table below. Well No. Dia./TD I Screen Slot Sand Pack Trans. Seal Grout Seal ' MW-101 2'134.5' 34.5-29.5' 0.010" #3 sand 35-27.5' 27.5-23.5' 23.5'-surface Groundwater was first encountered at approximately 12 feet below grade. A #3 sand filter pack surrounded and extended two feet above the 0.010 inch screened interval and was topped by a four foot bentonite pellet transition seal installed on top of the filter pack. A ' surface seal was achieved by pumping a neat cement grout (augmented with <4% bentonite). The well was surged using a clean surge block to achieve maximum filter pack density prior to installing the bentonite transition seal. The well was secured with a locking