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CIN CONTINENTAL MATERIALS CORPORATION <br /> The hydraulic performance at the intersection of the WS-3 Cross Channel and south flowing terrace <br /> channel is of concern to the DRMS. Higher flows and velocity in the cross channel may cause <br /> interference/backwater/reverse flow conditions in the terrace channel at these junctions, leading to <br /> overtopping and/or potential for significant erosion and significant water infiltration. Please provide <br /> design details for these critical junctions. <br /> Response: Intersections between terrace channels and down drain channels are extremely common in <br /> reclamation projects, and many of these intersections occur at the oblique angles shown on the <br /> comment.The Cross Channel has a slope of 30%through the segment identified by this comment, which <br /> will prevent any water pooling or backwater effects in the channel or in the terrace. Also,the invert <br /> elevation of the terrace channel will be above the invert elevation of the down drain channel,which will <br /> prevent backwater or erosion in the terrace. Figure G-2c has been prepared to present details on the <br /> terrace/cross-channel intersection. <br /> 33e. Water Capture Structure Details:The response is not adequate. The comment was misunderstood. <br /> The comment is meant to address the transition from native ground to engineered channels in fill <br /> material. How will the transition ensure runoff will not seep into the fill below the engineered channel? <br /> For example will cutoff walls be•installed? <br /> Response: The fill below the channel will be compacted fill,which will limit infiltration. A small amount <br /> of runoff will seep into the fill; however, this small volume will not impact the performance of the <br /> channel or the slope stability. <br /> 34. Benched vs Backfilled Highwalls:The response is not adequate,additional clarification is required. Of <br /> the 1.79 acres to be left as highwalls on Exhibit F-2, will this be benched. If so, what are the expected <br /> bench heights?If not, what is the slope? <br /> Response: Yes,the 1.79 acres to be left as highwalls on Exhibit F-2 will be benched.The highwall slope <br /> will be 30 feet tall and will be sloped at 62°.There will be a 15-ft wide bench.The highwall slope/bench <br /> design has not changed from the Amendment 03 design. <br /> 35a.Topsoil protection: How will topsoil be stabilized...The response is not adequate, additional <br /> information is required.The response indicates the slopes may be too steep to apply tackifier and that <br /> wood fiber mulch should be applied.The last bullet discusses broadcast seeding and mechanical <br /> techniques to rip/gouge the soil.The ripping or gouging the soil is good for seed bed preparation and <br /> retaining moisture, but it does little to stabilize the soil while waiting for vegetation to get established. <br /> What equipment do you propose for the wood mulch application (is there a power mulcher or other <br /> equipment that can reach these areas?)and how will seed be broadcast—by hand or do you have other <br /> equipment in mind?).Are erosion control blankets more appropriate? <br /> Pikeview Quarry Amendment 4, Response to Adequacy <br /> March 2,2020 <br /> 3 <br />