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WGIR, Southwest, Inc. The well boreholes will be drilled to a total depth of approximately 25 feet bgs with a Mobile Drill B-61 drilling rig, or equivalent, equipped with 10 to 11-inch outer diameter (O. D.) hollow-stem augers. Pre-cleaned augers will be used throughout the drilling operation to prevent potential cross contamination. The work will be performed under the supervision of a California Registered Geologist. The wells will each be constructed with approximately 15 feet of 4-inch O. D., schedule 40 PVC, 0.020" slotted well screen set from approximately 8 feet to 23 feet bgs, with the remaining pipe to surface consisting of 4-inch O. D., schedule 40 PVC blank well casing. Number 3 sand will be used as a filter pack to approximately 2 feet above the screened interval in each well. The wells will be surged to allow for filter pack settlement prior to placement of the annular seals. Immediately above the filter packs, seals consisting of a minimum of 5 feet of hydrated chipped bentonite will be placed. The wellheads will be secured with locking well caps and completed with 12-inch-diameter Emco-Wheaton traffic lids installed in minimum 24-inch square concrete pads. Following installation, the wells will be developed using a rig-mounted bailer. Generalized completion diagrams are attached as Figures 4 and 5. SOIL SAMPLING AND ANALYSIS Undisturbed soil samples will be collected for analysis at five-foot intervals from 5 feet bgs to the total depth of each boring (anticipated to be 25 feet bgs). The soil samples will be collected in accordance with EPA SW-846 procedures using an 18-inch long, 3-inch O. D. split-spoon sampler lined with 2.5-inch O. D. metal sample tubes. One of the sample tubes from each sample interval within each boring will be immediately sealed with Teflon film, a polyethylene cap, and toluene- free polyethylene tape. The samples will be labeled with all pertinent sampling information, and then packed on ice for subsequent delivery to a California Department of Health Services (CDHS)- certified laboratory for analyses. The soil in the remaining tubes will be described and logged by the field geologist in accordance with the Unified Soil Classification System (USCS). Sampling equipment will be decontaminated between sampling episodes utilizing a triple rinse method, consisting of an initial rinse with tap water, and a final rinse with deionized water. Each of the samples will be analyzed for NH3-N by EPA Method 350.2 and pH by EPA Method 9045. GROUND WATER MONITORING,PURGING,AND SAMPLING Prior to purging and sampling, depth to ground water in the monitoring wells will be measured to 0.01-foot accuracy from the top of the well casings using an electronic oil/water interface probe. A minimum of three to four well volumes of water will be purged from each of the monitoring wells prior to sampling using a vacuum truck. The wells will each be allowed to recharge to at least 80% of the static head prior to sample collection. 725.PRI.00 3 August 28, 2003