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p 3 Mr. Harlin Knoll Page 3 of 4 WORKPLAN The following workscope is proposed to further evalutte the nature and extent of groundwater impact at the site: Drilling, Well Construction and Soil Sampling Three monitoring wells will be installed at the site at the approximate locations shown on Figure 2. A C-57 licensed drilling contractor will advance soil bo ings using a hollow stem auger drill rig. The wells will be completed to depths of approximately 19 feet below ground surface (bgs), and will be constructed of 2-inch diameter, Schedule 40 PVC casing and 0.010". slotted screen. The wells will be screened from approximately 4 feet to 19 feet bgs to accommodate water level F fluctuations. Filter pack will consist of 2112 sand frorr the bottom of the wells to approximately 1 1.5 feet above the top of the screens. The remaining annulus will be completed with approximately 1.5 feet of hydrated bentonite overlain by concrete to the surface. At the surface each well will be fitted with a watertight, traffic rated well box and locking- well cap. Drilling and well installation will be conducted under supervision of an experienced geologist. The borings will be sampled at 5-foot intervals for stra igraphical concerns. All soil samples will be classified in accordance with ASTM Designation D2488-90, which is equivalent to the Unified Soil Classification System. Up to three soil samples r boring will be submitted for laboratory analysis, including the samples collected from the capillary fringe. Samples selected for analysis .I will be immediately capped, identified and placed in an ice chest refrigerated to a temperature of approximately 4°C for shipment to a State-certified laboratory under chain of custody protocol. ; Soil samples will be analyzed for TPHg using EPA Method 8015M, and BTEX and MTBE using EPA Method 8020. Any positive results for MTBE will be confirmed using EPA Method 8260B. Well Development, Surveying and Groundwater Santpling '! The elevations of the well casing collars will be surveyed to an accuracy of 0.01 feet. A minimum of 48 hours after completion, an experienced field technician will measure static depth to water, and then develop the wells by pumping and surging until turbidity is minimized. A minimum of three casing volumes will be purged from each well. After pH, temperature, and electrical conductivity h ve stabilized and water has recharged toa at least 80% of static levels, groundwater samples will be collected into the appropriate containers and placed in an ice chest refrigerated to a temperature of approximately 4°C. The! samples will be shipped to a State-certified laboratory under chain of custody protocol and, analyzed for TPHg using EPA Method 8015M, BTEX using EPA Method 8020, and il oxygenated gasoline additives including MTBE using EPA Method 8260B. .I 6:1Data1GROUNDZ,E\Barnyard-Mansu\Reports\WKPLAN_MW5-MW7.doc