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CGRS, Inc. <br />2.7 Aquifer Characterization <br />In order to estimate [he hydraulic conductivity (K) of the aquifer, a minimum of four slug tests will be <br />conducted at monitoring wells deemed to be representative of the aquifer at the site and in the downgradient <br />area. Water level measurements and times will be recorded using an InSitu Troll SP4t)~Q pressure <br />transducer. The test results will be input into standardized software, utilizing the Bouwer Rice Method, to <br />determine hydraulic conductivity in the aquifer at each well. The average groundwater Flow rate (v) can be <br />estimated using the following equation: <br />v=Ki/~ <br />where: <br />v =average groundwater Flow rate (ft/day) <br />K =hydraulic conductivity (ft/day) <br />i =hydraulic gradient (fVft) <br />~ =porosity (dimensionless). <br />Permeability testing will be conducted in wells completed within the ash on a periodic basis to evaluate <br />possible changes in hydraulic conductivity with time. <br />2.8 ContinPencv Plan and Abatement <br />If adverse changes [o water quality as predetermined by all interested parties are observed during testing, the <br />coal ash will be immediately excavated and stored in a dry impoundment within the Varra property <br />boundary. Native soils will be placed in the trench and water quality will be monitored on a monthly basis <br />for the constituents of concern. Additional remedial activities, if needed, will be commensurate with the <br />extent and degree of water quality degradation. The water quality monitoring schedule is rigorous and <br />should allow for the detection of adverse environmental conditions long before any significant degradation <br />could occur. If the project is terrrtinated it is likely that the only corrective action that will be required is <br />source removal and monitoring. Monitoring will be conducted until i[ can be demonstrated that points of <br />exposure (POEs) are not subject to impact. <br />Any other required remediation will be dependant on the physical and chemical characteristic of the <br />contaminate of concern. Corrective action could include oxidant/reductant injection, permeable reactive <br />barrier, groundwater pump and treat or any combination of the above. Analytical data generated from the <br />column experiment indicates that boron and selenium are the most leachable elements (nonmetals). As such, <br />n is likely that the most effective form of remediation would be groundwater recovery and treatment. <br />Previous analytical studies show that a single well pumping less than 10 gpm would capture all groundwater <br />bypassing the trench. Treaunent for boron or selenium could be accomplished by ion exchange or reverse <br />osmosis. Ddution with natural a-aters is also an option. <br />5 <br />