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Mr.Roger Doak <br /> Coal Ash Pilot Projoct Proposal <br /> June 26,2000 <br /> Page 5 <br /> A United States Geological Survey investigation documented groundwater occurrence and <br /> movement near the study area. Underflow calculations in the vicinity of the study area indicate <br /> that 600 acre feet of water passes across a two mile section of the alluvial valley. If the <br /> average depth to bedrock varies between 20 and 30 feet below ground surface then the average <br /> hydraulic conductivity is calculated to vary between 97 and 147 feet per day. Assuming a <br /> hydraulic gradient of 0.0023 feet per foot and a porosity of 0.27 the seepage velocity (actual <br /> groundwater flow velocity) is estimated to vary between 0.83 and 1.25 feet per day. A map <br /> depicting the pieziometric surface of the local aquifer is presented in Attachment E. <br /> Depending on the local the groundwater flow direction the downstream distance to the Varra <br /> property boundary could vary between 400 and 800 feet. Compliance wells will be installed <br /> up, down and cross gradient to the proposed trench. Two downgradient compliance wells will <br /> be installed no more than 200 feet downstream of the trench. At least two action wells or <br /> sentinel wells will be installed within 50 feet on the downgradient side of the trench. <br /> Varra Companies can fulfill the financial assurance with either an addition their existing <br /> Surety Bond with DMG or can provide the state with a separate bond. In any event, as <br /> required the financial assurance will be established prior to accepting the ash as will the record <br /> keeping and reporting requirements once the project is deemed technically feasible. <br /> 6. The monitoring well network depicted on Figure 3 in Attachment E has been modified to shows <br /> eight monitoring points around the trench. Though the locations are conceptual, wells will be <br /> located up, cross and down gradient of the trench. If this project is deemed technically feasible <br /> at least four monitoring wells will be installed three months prior to the pilot project to <br /> determine ground water flow direction. Water levels will be obtained on a weekly basis prior to <br /> the project and no less than a monthly basis thereafter. Varra Companies will install as many <br /> wells as required to adequately monitor the site and to account for variations in groundwater <br /> flow direction. In addition, vertical variations in water quality and hydrology will be measured <br /> by constructing wells which are screened below the ash deposit as depicted in Attachment F. <br /> Of the eleven locations one point will be a nested well set which will consist of two wells <br /> completed at different depths to monitor vertical changes in water quality. <br /> 7. Varra Companies wishes to amend its contingency plan. As mentioned previously, if removal <br /> of the ash is required it will be characterized and transported to an acceptable landfill for <br /> disposal. <br /> 8. We agree that groundwater quality actions levels and compliance points need to be established. <br /> Background levels for various constituents should be accounted for when considering action <br /> levels. In general, we recommend the established standards for groundwater (Regulation #41, <br /> (5CCR 1002-41) be used as action levels. For constituents with multiple action levels we <br /> propose that primary standards be used. If a standard is exceeded confirmation sampling will <br /> be performed within one week of receiving analytical results. If the MCI, is exceeded in the <br /> confirmation sample corrective action will commence. If a standard is exceeded and the <br /> analytical results are within acceptable error limits, we propose no action be mandated. <br />