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Lodi -Quartefly Groundwater Monitoring Page 2 The three groundwater monitoring wells were installed approximately ten feet into the groundwater aquifer. The well locations are provided in Figure 1. Groundwater was encountered at a depth of 50 feet BGS during drilling activities. The screened interval consists of 2-inch diameter Schedule 20 PVC casing (0.02 slot) that extends from the end of hole to five feet above the groundwater surface. Blank 2-inch diameter Schedule 20 PVC casing extends from the screened interval to the ground surface. The sand pack (#2 grade) extends from the bottom of the boring to five feet above the screened interval. A pelletized bentonite seal (2 feet thick) lies directly above the sand pack. The remainder of the annular space is filled with grout. A locking end cap was placed at the top of each casing. The wells are protected at the ground surface with flush mounted steel Christy boxes set in concrete. Twenty-four hours after the third well was installed, five casing volumes of water were purged from monitoring well SRK-MW1, while well SRK-MW2 and SRK-MW3 were bailed dry after lfour casing volumes were purged. The casing volumes were based on actual static water level measurements made on the day of sampling. The wells were purged using a teflon bailer and dedicated nylon rope. The bailer was thoroughly cleaned before purging each well using non- phosphate soap followed by a deionized water rinse. All water purged from each was placed in 55-gallon, closed-top drum. No petroleum odors or iridescent sheen were observed in water evacuated from any of the monitoring wells. 2.0 SCOPE OF SERVICES The scope for this phase of work included: • Property survey to accurately locate the position and elevation of the monitor wells. ' • Purging and sampling the wells according to PHS/EHD guidelines. ' • Shipping the groundwater samples under correct chain-of-custody procedures to a California licensed Laboratory for analyses. ' • Determining the localized groundwater gradient by measuring the static water level relative to the top of casing. i3.0 GROUNDWATER GRADIENT SRK retained the services of Cella Barr Associates to provide elevations at the top of well heads relative to a known datum, and the locations of the wells relative to on-site structures. This information is provided on Figure 1 (located in the pocket at the back of this report). Static water levels were measured on April 6, 1992, using a Solinst Water Level Indicator. Copies of the static water levels are provided in Table 1. zsn+-ra�orcr va.z. Steffen Robertson and Kirsten