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Introduction <br /> RP-A was originally permitted as Technical Revision 72 in the fall of 2019. Blue Mountain Energy would <br /> like to change the location of the subsoil and topsoil stockpiles. Some topsoil and subsoil has been <br /> placed in the originally permitted locations, but as stockpiling progresses, it would be advantageous to <br /> shorten the haul distance and eliminate conflicts with the ongoing operation of haul trucks. The <br /> proposed configuration is shown on the revised Map 162. <br /> Hydrology <br /> The new stockpile areas drain to the Red Wash Reservoir#2 that is designated as our point of <br /> compliance. In the SedCAD calculations,the sub watersheds upstream from Structure 32 were revised to <br /> reflect the disturbance of 12.16 acres for the new stockpile locations.The revised results for the 10, 25, <br /> and 100-Year analyses are found in the respective following sections. <br /> Table 1 shows a comparison of the flow rates into and out of the BLM Red Wash Reservoir#2 for the <br /> previously permitted conditions(Pre MR-178)and the proposed conditions contained herein (Post MR- <br /> 178). <br /> Table 1. Pre and Post MR 178 Flow rates <br /> Pre MR-178 Post MR-178 <br /> Storm Flow Into Flow Out Flow Into Flow Out <br /> Pond (cfs) (cfs) Pond (cfs) (cfs) <br /> 10-Year 24 3 28 4 <br /> 25-Year 41 12 44 13 <br /> 100-Year 77 45 81 49 <br /> The increase in flow rates is relatively insignificant and does not warrant changes to the structure <br /> design. <br /> Sedimentology <br /> The reservoir reduces the peak settleable solids concentration to 0.01 ml/I during the 10-year storm. <br /> This is well below the permitted limit of 0.5 ml/I. <br /> Blue Mountain Energy 2 Illustration 60 Addendum 1 <br />