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Mr. Travis Marshall <br />Mr. David Bird <br />Division of Reclamation, Mining, & Safety <br />May 11, 2011 <br />• Page 5 <br />Response to DRMS Comments (from D Bird 2/21/11) <br />1. Section 5.2.1 pg 17: Regarding the statement that major surface water divides coincide <br />generally with ground water divides, please provide hydrologic data to support this <br />statement. <br />The "major ground water divides" referenced in DRMS Comment 1 above and <br />referred to in the original NOI submittal are pertinent to the regional <br />groundwater system as described by Robson and Saulnier, 1981. A <br />pertinent illustration from Robson & Saulnier is provided as Figure 13 <br />"Potentiometric Surface for the Upper Aquifer" in the original NOI <br />submittal dated 12/29/2010. <br />The "major ground water divides" in that reference actually refer to the <br />divides at the margins of the graphic in Figure 13. The map illustrates <br />that all water that falls on the Piceance Basin shown in the diagram <br />either leaves the basin immediately as surface flow, or discharges <br />eventually to Piceance Creek and Yellow Creek within the confines of the <br />geologic basin, which is what defines a closed basin, and also shows that <br />the groundwater divide is different from the topographic surface water <br />• flow/divide within the Basin. The purpose of the map, as used in the <br />discussion was to illustrate that the Piceance Basin in the area of <br />interest is a closed basin; that ground water does not enter the basin <br />from outside the basin. <br />2. Section 5.3.1 pg 18: Regarding the statement, "Ground water flow is not influenced by <br />topography..." This statement seems to conflict with the statement above from page 17. <br />Please clarify. <br />The statement in question refers most specifically to ground water in the <br />Uinta Formation, but is applicable to all water bearing units in the <br />Parachute Creek Member of the Green River Formation below the Uinta. The <br />statement points out the remarkable fact that even though the Uinta does <br />outcrop across most of the basin, the potentiometric surface within the <br />Uinta shows little to no evidence of topography affected flow. This is <br />illustrated in Figure 17 in the original NOI submittal. <br />3. Section 5.3.2 pg 19: Please provide explanation of the temperature and density <br />corrections that are applied to the potentiometric ground water levels of Figures 17 <br />through 22. <br />Data depicted on the maps in question (Figures 17 - 22) were adjusted to <br />a common temperature (i.e., 20°C) and density (i.e., fresh water) in <br />order to compare more correctly the relative heads and potential for <br />• cross flow of each water bearing unit. In addition, for the relatively <br />higher TDS L4 and L3 WBIs, a common elevation datum was chosen to