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well development is to promote settlement of the sandpack prior to installing the bentonite seal in order to maximize filtering capacity of the wells. Full development of the wells will be performed at least 48 hours after well completion. This will include additional surging and bailing along the screened interval to remove fine particles from the sandpack, and after several volumes of water have been removed, the wells will be pumped (or bailed) until the discharge water is relatively free of sand or silt. After well development, the elevation of the monitoring wells (i.e. top of casing) will be surveyed to mean sea level. A benchmark located on the bridge where Undine Road crosses Middle River(Geodetic Survey Hub W474 at 22.98 ft MSL) will likely be used as the survey datum. All surveyed elevations will be performed to an accuracy of 0.01 foot. 1 Monitoring Well Sampling and Analytical Procedures I Prior to purging, the water level in the wells will be measured using a Solinst immersion probe (or equivalent) to an accuracy of 0.01 foot and the wells will be sampled with a clear bailer(or measured with an interface probe) in order to inspect the well for the possible presence of floating hydrocarbons. Each z monitoring well will be purged prior to collecting groundwater samples for chemical analyses. During the J _ P-urgmg process, approximately three to five well volumes of groundwater will be discharged from the well using either a pump or bailer. The well will be properly purged when the physical parameters of the Jgroundwater(i.e., pH, temperature, and conductivity) have stabilized. If the well is evacuated prior to the removal of three to five well volumes, a sample of the groundwater will be collected when the water levels Jis sufficient to provide a representative sample (i.e., return to 80%or more of the static water level). JSamples of the groundwater will be collected from each well using a Teflon® or disposable bailer which has been washed in a solution of Alconox or non-phosphate TSP followed by several rinses with potable Jwater. The groundwater samples collected from each well will be decanted into two appropriately prepared 40-m1 organic analysis (VOA) vials and two 1-L amber bottles. The sample containers will be labeled with Jthe site location, well I.D. number, date, time, and initials of the person collecting the samples. Care will be taken when transferring the water from the bailer to the sample containers to avoid turbulence and the JVOA vials will be filled above the top of the opening to form a positive meniscus so that no headspace will be present. The samples will then be placed in an ice chest with the completed chain-of-custody form and I maintained at 4°C until delivered to a State of California-certified analytical laboratory (Chromalab, 1 cca/03/10/95 09:38 AM(0688brpt.doc/ntw12) 4-7