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The annular space between the well screen was filled with clean #3 Monterey Sand as a filter pack. The sand filter pack extends 3 feet above the top of the well screen. Three (3) feet of bentonite chips were placed above the sand as an annular seal. The remainder of the annular space was filled with quick-setting bentonite cement grout. The top of the casing was provided with a locking cap with a rubber gasket and enclosed inside an aluminum vault with a traffic-rated steel cover. The area around the vault was paved with cement. The monitoring well constructions are shown in the Monitoring Well Construction Diagrams (Appendix VII). 4.4 Monitoring Well Development The monitoring wells were developed on October 6, 1995, 40 hours after installation, by surging, swabbing and bailing to remove the clays and silts on the face of the aquifer opposite the well screen. Well development is conducted in order to establish hydraulic communication between the aquifer and the well. ' Sufficient volume of water, using a purge factor of 4 times the volume of water contained within the well casing, was bailed from each well. Conductivity, pH and temperature readings of bailed water were monitored during well development to determine if these parameters stabilized to within 10 per cent deviation from average readings. i The purged development waters were placed in 55-gallon DOT-approved steel drums and stored onsite in a locked storage bin pending disposal. ' 4.5 Groundwater Sampling Procedures Water samples were obtained from each well two (2) hours after purging to allow fine sediments to settle. A dedicated disposable plastic bailer was used to collect the water samples. Water in the bailer was released from the bottom into 40 milliliter glass VOA vials and 1 liter amber glass containers provided with caps lined with Teflon septa. The sample containers were filled to overflowing to eliminate head space which might allow volatile organics to come out of solution. The glass vials and liter bottles were labeled, double-bagged in plastic bags, placed on ice in a portable cooler and entered into a Chain of Custody form. The samples were delivered the next day in a chilled condition to Centrum Analytical ' Laboratories in Redlands, California for analysis. 4.6 Monitoring Well Survey ' The existing monitoring well MW 1 and the newly installed monitoring wells MW2 and MW3 were surveyed on October 5, 1995 by Mr. Tom Morrow of ' Morrow Surveying, Sacramento, California. The wells were surveyed to establish their spatial relationships and their elevations. The well survey map is CRC Environmental Risk Management,Inc. Project#2100-250-2 American Savings Bank 222 North EI Dorado Street November 3, 1995 Stockton,California 7