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i URS Mr Harlin Knoll Page 3 San Joaquin County Environmental Health Department May 19, 2003 Drilling and Monitoring Well Installation Prior to drilling, an access agreement was obtained from the owners of the Union Safe Bank property Well installation permits were obtained from the SJCEHD, and all drilling locations were cleared for utilities by Underground Service Alert On March 5, 2003, Woodward Drilling of Rio Vista, California, drilled and installed an on-site groundwater monitoring well (MW-5) A soil boring was drilled to a total depth of 98 feet using a hollow stem auger (HSA) drill rig with 8-inch-outside-diameter (OD) augers to accommodate the installation of a 2-inch diameter groundwater monitoring well Soil samples were collected at 5-foot intervals above 40 feet bgs and continuously below 40 feet bgs with a modified California split-spoon sampler The soils were logged by a URS geologist according to the Unified Soil Classification System Soils were field screened for the presence of volatile organic compounds with a photoionization detector (PID) No soil impacts were indicated by the PID readings or visual observations Depth-discrete soil samples were not submitted for analysis First groundwater was encountered at 51 feet bgs Boring logs are presented in Attachment A On-site monitoring well MW-5 was constructed using 2-inch-internal diameter (ID), schedule 40, flush- threaded polyvinyl chloride (PVC) well casing Five feet of 0 020-inch machine-slotted well screen was set from 65 to 70 feet bgs across a two-foot sand layer No sand was encountered at MW-5 between 71 and 98 feet bgs, therefore, the well was screened at this depth and this interval was backfilled with bentonite pellets On March 6, 2003, Woodward Drilling drilled and installed two offsite monitoring wells (MW-6 and MW-7) at the locations shown on Figure 2 Soil samples were collected at 5-foot intervals and logged by the methods outlined above Decontaminated augers were used for all three of the soil borings Down-hole sampling equipment was decontaminated between samples by washing in a non-phosphate detergent solution Off-site well MW-6 was screened in a sand layer between 55 and 60 feet bgs with 0 020-inch machme- slotted well screen Offsite well MW-7 was screened in sand and gravel from 45 and 60 feet bgs with 0 020-inch machine-slotted well screen A Monterey No 3 silica sand filter pack was installed from the bottom of the each well screen to 2-feet above each well screen A 3-foot bentonite seal was placed above the sand pack, and neat cement was used to seal the remaining annular space to the surface Surface completions consisted of a 12-inch flush-mounted well box, and locking, water-tight well cap were placed on the wells Well construction details are shown on the boring logs in Attachment A K 1WprocessU5 6P ARC01l 11911Well Installationlwell installation repor 03 doc