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r 7-Eleven/Stockton 14 May 1990 WELL I.D. TOTAL DEPTH SCREENED INTERVAL (feet) (feet) MW-17A 79 74 - 79 MW-17B 73 68 - 73 -- MW-17C 63 28 - 63 The monitoring wells for the well cluster were constructed of 2-inch-diameter PVC blank casing and 0.020-inch machine- slotted PVC well screen. The sand pack, consisting of Lonestar No. 2/12 sand, was set in the annular space from the bottom of the screened interval to 2--feet above the top of the screened interval. Above the sand pack, a minimum 3-foot-thick bentoiite seal was set in the annular space by pumping through a 1-inch tremae pipe lowered to the top of the sand pack. Above the bentonite seal, the annular space was filled to the surface with a sand-slurry cement grout using the previously-described tremie -; method. The wellheads were finished with street-rated, "Christy boxes" grouted in glace within a 2-foot by 3-foot cement pad, and locking, water-tight caps to protect the well from damage and -• from the entrance of surface water. well completion details are presented on the drill logs (Appendix F) . Following well completion, the monitoring-well cluster (MW-17 A, B, C) was gauged and sampled. Prior to sampling, each well was developed by a combination of surging and bailing. Between 25- and 40-gallons of water were removed from each well, assuring a fresh flan; of water from the aquifer to the wells. The wells were then allowed to recover to at least 80 percent of -- their original volume before sampling with an EPA-approved TeflonR sampler. Groundwater samples were stored in 40--milliliter glass VOA vials, labeled, placed on ice and transported under Chain-of-Custody Manifest to GTEL, in _ accordance with Groundwater Technology SOPS 9, 10, 11 and 12 ✓ (Appendix D) . Laboratory results of groundwater samples are presented in Appendix E. TEcfi.NO1.0GY,INC. 6 i