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ti Site Characterization and Soh.,emedialion Plan. 7500 Mess Eleventh Street, Tracy, LA Page 16 Code regulatory requirements, a Well Closure Report (Form 188), together with attached boring logs and construction details, will be completed for each of the closed wells and filed the California Department of Water f Resources with copies to th JCHCSA, 2 Survey of Well-head Locations and Elevations The locations of the new wells will be surveyed and the elevations of both the top of casing and the well-head box cover frame of each will be determined relative to mean sea level (MSL)- ``. GROUNDWATER-QUALITY MONITORING Following installation and development of the groundwater-quality monitoring wells, an initial round of samples will be recovered from each and the samples submitted for analysis. As is discussed later, it is expected that additional rounds of sampling and ani I,sis will be required. The procedures described below will be used in each instance j Determination of Groundwater Elevations Prior to each round of groundwater sampling, the depth from the top of the casing to the water table will be measured using a water-depth meter. That data will be used to compute the groundwater table elevations relative to MSL. The computed groundwater table elevations will be used to produce contour maps of the groundwater table and determine the direction and magnitude of the groundwater flow gradient. i Sampling Procedure i >i Prior to recovery of a groundwater sample from a well, the well will be purged of a minimum of 5 casing volumes_ The purge water will be temporarily held in 50-gallon steel drums. Samples will be recovered from each monitoring well to be sampled using a dedicated bailer that will be left suspended in the well casing when not in use. -� Water brought to the surface in the hailers will be decanted so as to completely fill clean glassware supplied by the laboratory. The sample vials will then be tightly closed, labeled for identification, entered into chain-of-custody control and packed on chemical ice for transport, within 24 hours, to Chromalab's laboratory in Pleasanton, California. : r Following completion of sampling, the depth to groundwater in each monitoring well sampled will be re-measured and checked against the depth measured prior to the start of well purging This will provide information on ( well-recovery rates and indicate whether or not representative samples of sic