2012-03-07_PERMIT FILE - C2010088A (17)

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2.04.7 Hydrology Description same well as is currently being monitored. As previously described the current monitoring well RW -2 was installed at a later date and is located northeast of the acid sludge landfill. There is no well completion log or other as -built drawings available for this well. The total depth and stickup were field verified and the best available information was added to the typical completion diagram provided in Exhibit 3. The typical completion diagram in Exhibit 3 provides the most current and best available information for the four active monitoring wells RW -1 through RW -4. Ground water was encountered by the four monitoring wells in the saturated alluvial material overlying the low permeability Mancos Shale. The depth to water in the four wells is currently either in the lowest portion of the silty clay layer or within the alluvium (ranging from about 11 to 20 feet). Ground water elevations, as measured in the four monitoring wells in June 2010, indicate the ground water flow direction is from northeast to southwest towards the Colorado River. The approximate elevation of the Colorado River is 4440 to 4441 feet above MSL, compared to ground water elevations of (RW -2) 4461 at the north end of the property to (RW -3) 4448 at the south end of the property. Given that the ground water flow direction is towards the river from the upland areas to the north and the river is several feet lower in elevation than the June ground water elevations, it is unlikely that the ground water beneath the proposed loadout facility is directly related to the Colorado River. It is possible that ground water beneath the property may, in part, be the result of irrigation in the upland areas, using water from up river diversions. The water quality of the alluvial ground water beneath the property indicates that the alluvial ground water originated in the Mancos Shale or at least traveled through the Mancos Shale. The alluvial ground water quality is typical of ground water quality of marine shales in western Colorado. Total dissolved solids range from 5,800 to 8,800 mg /L, with an average of 7,300 mg /L for the four monitoring wells. The water is predominantly a calcium- sodium sulfate water with elevated dissolved iron. For comparison, the Colorado River upstream and downstream of the property had total dissolved solids of about 600 mg /L in June 2010. Detailed water quality information is presented in Volume I, Exhibit 3. The first and third quarter 2010 groundwater samples were tested for Total Petroleum Hydrocarbons (TPH), benzene, toluene, ethylbenzene, and Permit Application 2.04 -15 07/11