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6. The ditch D49 SEDCAD printout is unclear. In the time of concentration details (page EXH 19(22) -49), there are <br />two times listed for SWS #2 for Structure #2: 0.055 hour and 0.377 hour. Please explain. It would be very useful <br />(but not necessary) to provide a schematic and/or map showing structures, sub - watersheds, and flow paths for D49 <br />and other ditches. <br />NECC: There are two subwatersheds for Structure #2. One subwatershed is associated with the upland area, the other <br />is associated with the disturbed are that is contributing flow to the channel The large majority of the runoff in <br />ditch D49 is from the upland area, however, there is a small portion of runoff that will be generated from the berm <br />that will be constructed between D49 and the various portions of the collection ditch in the outslope of the waste <br />pile. <br />Division: This portion of the model is still unclear. The NECC explanation does not address why there are two times <br />listed for SWS #2. Furthermore, the Subwatershed Hydrology Detail table lists three SWSs, not two. <br />NECC: Two values were listed for Structure #2. The problem has been corrected, and now only one time of <br />concentration is shown for Structure #2 (Ditch 49- (2 %)). As a result of the change in time of concentration for <br />Structure #2, the peak floe for D 49 -2% has changed as well as downstream ditch segments. Therefore, please see <br />revised pages EXH. 19(22) -50, 52 to 58, and Table 20 and Table 21. <br />Division: Response is sufficient. <br />7. The location where ditch D49 would originate was inspected. Please provide more details on the design of the <br />upper end of this ditch to determine if it is sufficient to prevent flow down the drainage from impacting the <br />proposed DWDA. Additionally, it appears that the proposed location of ditch D49 pre- disturbance goes up- <br />gradient at the upper section. Does NECC plan on cutting the slope back or cutting the ditch deep enough to <br />allow flow down the drainage and into ditch D49? <br />NECC: Please see new D49 Typical section on Map 14. A 10' wide by 4' high berm (minimum) will be constructed <br />between D49 and the DWDA diversion ditch. At the beginning of D49 there is a 6' berm, plated with riprap <br />which will provide adequate protection to keep the diversion ditch within its channel bank. <br />Division: It does not appear that Map 14 contains a typical section for D49 as stated in the NECC response. There is a <br />cross section for D31, but it is not stated that this is also representative of the section for D49. Regardless, a <br />section does not provide the detail needed to illustrate the design of the upper end of this ditch; this design must <br />direct flow away from the proposed DWDA. Furthermore, the berms that are described should be shown on Map <br />14. <br />NECC: The reference should have been to a typical section shown on Map -12. A phone conversation with Rob Zuber <br />on July 23, 2012 cleared up DRMS' issues with the caveat that a note should be added to Map -12 stating flow will <br />be directed away from DWDA #3. In addition, the berms are now shown on revised Map 14. <br />Division: Response is sufficient. <br />2 <br />