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Response to DRMS Adequacy Review(2)—Cotter-9 Mine Reclamation Plan Amendment <br /> ...� MISSING SUBBASIN 3 <br /> (2.45 <br /> _ FIGUliE 1. <br /> s <br /> The area in blue highlighting shown on your Figure 1 of the comments has been <br /> added to Basin 30B to include the area around the proposed detention pond. The <br /> runoff entering the detention facility was reanalyzed. This area was originally <br /> excluded because the runoff from it was intended to be diverted around the pond <br /> by the channels located just upgradient from the north edge (this applies to your <br /> comment 13a and associated Figure 3). These proposed diversion channels have <br /> now been removed allowing this area to flow into the pond via overland flow. The <br /> detention volume, outlet structure, and chute analysis were reanalyzed. Drawings <br /> illustrating this are found in Attachment 4 with the calculations in Attachments 1 <br /> and 2. <br /> b. The subbasin area contributing to the existing road ditch O(ref. Sheet 3 label) <br /> has been reduced. Please reference Figure 2 (attached) to see the area <br /> (highlighted in light blue)DRMS deems necessary to address contributing runoff <br /> to existing road ditch O and ensure adequate design capacity and stability. <br /> Please revise the hydrology estimates and make the necessary adjustments to the <br /> channel analyses for capacity and stability. Section 20-1 may need a flatter slope <br /> to be considered for the capacity analysis. (Note this area was included in the <br /> 911212013 submittal). <br /> The original basin 20B was reduced in size when it was determined that the <br /> existing roadway (shown on the drawings and now making up part of the eastern <br /> boundary of 20B) intercepts and deflects runoff from the small area above it (which <br /> 7 <br />