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Environment, Inc. Page 6 <br /> Ellicott Sand&Gravel LLC -M-2017-063 <br /> Adequacy response 01 <br /> page 14. What is the source of the grass seed recommendations and why is blue grama <br /> not included? <br /> The soils and vegetation information was provided by Greg Langer the NRCS District <br /> Conservationist for El Paso County. The copy of his recommended seed mix as shown on <br /> Page 57. I have no idea why he choose not to include Blue Grama. <br /> 13. Post-Reclamation site drainage: Rule 6.4.5(2)C requires the Applicant to explain how the <br /> reclamation plan meets the requirements of Rule 3.1.5(1). Appropriate final grading <br /> topography and Rule 3.1.6(1), disturbance to the prevailing hydrologic balance do not <br /> appear to be adequately addressed. The proximity of highwalls shown on the referenced <br /> Exhibit F Map which extend below the thalweg of the adjacent ephemeral drainage and <br /> which are in the 100-year floodplain is likely to have an significant impact on the <br /> hydrologic balance should a flood overtop the highwall crest. Please discuss how stream <br /> capture by the pit will be protected. <br /> There is not way to stop a catastrophic flood from entering any mine that has a floor <br /> below the thalweg of an adjoining stream unless levies are built around the area to keep <br /> the flood water out. This is not practical nor do we believe we could obtain the necessary <br /> permits to build them in the flood plane. Urban Drainage has published guidelines that can <br /> be followed so mining can be compatible with mining in a flood plane. Using wider setbacks <br /> and armoring to protect the banks is proposed so that after a large flood event, the creek <br /> will remain in the original channel. <br /> In this case there is no constant flowing stream to capture except in uncommon <br /> circumstances during extreme flooding. Mr. Doug Hollister the Division 1Oth Water <br /> Commissioner told me that in his ten-year with the Division that there has only been 2 <br /> times where water exited the Upper Black Squirrel Drainage basin. This suggests it is <br /> more, an unusual event when any large volumes of water flows within the defined banks let <br /> alone enters the flood plane area adjacent to the channel. <br /> The interior bank grading is proposed at 3:1, that is shallower then what is required in the <br /> rules for above water areas and is consistent with the chosen reclamation plan of <br /> returning the mined areas to rangeland. No ground water will be intercepted so the <br /> hydrologic balance to the ground water table will not be impacted. During a catastrophic <br /> flood event (100 year or greater) the water that enters the excavated areas will actually <br /> help recharge the groundwater in the Upper Black Squirrel Creek Basin and allow the basin <br /> to capture more water then if it were to runoff the surface and exit the basin. Any <br /> water that remains in the holes after the 72 hours will be replaced as required from an <br /> approved source. <br /> We foresee a time period where eventually the mined areas could be refilled with <br /> sediment if flooding were to occur on a frequent basis. The gardant of the slope into the <br />