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Mr Mike Infurna Page 2 wells (MW5 through MW7) ranged from 56 60 feet btoc to 57 41 feet btoc Depth to groundwater in C Zone well MW 1D was 58 57 feet btoc Since previously measured on June 13, 2005, water levels fell an average of 8 38 feet in the A Zone wells, 8 31 feet in the B Zone wells, and 8 31 feet in the C Zone well Water level data are summarized in Table 1 Monitoring well locations are shown on Figure 2 Field data sheets are included in Attachment A Groundwater elevation was determined in each well by subtracting the depth to groundwater measurement from the respective surveyed wellhead elevation On August 29, 2005, the potentiometric surface of the A Zone wells ranged from 39 02 feet to 39 09 feet below mean sea level (MSL) The potentzometric surface of the B Zone wells ranged from 38 82 feet to 39 25 feet below MSL The potentiometric surface in C Zone well MW11) was 39 11 feet below MSL Due to the complexity of the well depth/potentiometric surface relationship, groundwater gradient was interpreted in several ways Figure 3 interprets the gradient using data from the A and B Zone wells together Indicated flow is predominantly toward the northwest at a gradient that ranges from approximately 0 0015 ft/ft to 0 003 ft/ft Potentiometric surface maps utilizing data from the A and B Zones separately are depicted on Figures 4 and 5, respectively Flow 1n both the A and B Zones is interpreted to be toward the northwest at a gradient of approximately 0 0015 ft/ft Groundwater Sampling On August 29 and 30, 2005, the site wells were purged and sampled During purging, . temperature, pH and electrical conductivity parameters were measured Purging continued until these parameters had stabilized A minimum of three well casing volumes was purged from each well Purge water was contained in appropriately labeled DOT-approved 55-gallon drums Purge logs are included in Attachment A Groundwater samples were collected after adequate groundwater recovery Samples were collected in sealed, preserved VOAs and stored in an ice chest refrigerated to a temperature of approximately 4' C Samples were delivered under chain of custody protocol to Argon Laboratories (FLAP #2359) Sample analysis consisted of gasoline oxygenate additives, 1,2-DCA and EDB using EPA Method 8260B, BTEX using EPA Method 802113, and TPHg using modified EPA Method 8015M Well Destruction On September 13, 2005, under the supervision of a Ground Zero geologist, Water Well Technology, Inc (C57 License #731133) destroyed the inactive domestic well located at the Frontier Motel, 2639 N Wilson Way The well was destroyed in response to the San Joaquin County Environmental Health Departments (EHD) letter dated August 12, 2005, formally requesting well destruction The Frontier Motel is located across Wilson Way from the Harry's Auto Mart fuel leak site (Figure 2) In April 2003, levels of the gasoline additive 1,2- dichloroethane (1,2-DCA) exceeding the State of California MCL were discovered in water from the supply well Interim measures to ensure a safe water supply for the motel were implemented including trucked-in water and carbon filtration In November 2004 the motel was connected to the municipal water supply and the well was inactivated San Joaquin County Environmental Health G 1GROUNDZEIHARRYS1Reports\QMRUOO513QM2005a doc