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File No. 20-3937-01 KLEtNE'ELDER September 3, 1996 4.4 MONITORING WELL DEVELOPMENT AND SAMPLING On July 22 to 24, 1996, the three monitoring wells were installed on site. Prior to placement of the annular (bentonite) seal, the filter pack was surged to allow the pack to set. On July 29, 1996, the monitoring wells were further developed by pumping (2" Grundfos Redi-Flow 2®)and surging to remove sediment laden water from the wells, set the filter pack, and increase the effective hydraulic radius of the wells. In excess of 10 well casing volumes if water were removed from each well. The well development and sampling procedures are explained in Appendix B, Kleinfelder Field Procedures. On July 30, 1996, monitoring wells MW-1, MW-2 and MW-3 were sampled by bailing. Prior to purging the wells, each well was checked for floating product with a clean disposable bailer. None of the three monitoring wells had a product layer, sheen, or odor. Water samples (sample #13165 from MW-1, sample 413164 from MW-2 and sample #13163 from MW-3) were collected in container's supplied by Sequoia Analytical of Sacramento, California. Well sampling procedures are described in Appendix B, Kleinfelder Field Procedures. The.Purge Characterization and Sample Logs are included in Appendix E. 4.5 MONITORING WELL ELEVATION SURVEY Relative elevations for the top of each 2-inch PVC well casing were surveyed by Kleinfelder personnel on August 20, 1996. The coordinates were tied to a temporary benchmark (painted location along Shaw Road southeast of MW-1 on the west shoulder of the road). The benchmark elevation was arbitrarily set at 103.16 feet. The elevations of the 3 wel is based off the arbitrary benchmark elevation was: MW-1 103.35 feet MW-2 104.32 feet MW-3 102.51 feet The depth to groundwater was measured from a set location at the top of each casing (mark on north end of the top). The depth-to-water was then subtracted from the corresponding casing elevation to provide a groundwater 'surface elevation at each well. The water surface elevations are used to estimate the groundwater gradient direction. 20-3937--011MR960189 Page 9 of 18 01996, Kleinfelder, Inc.