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;~. <br />C7 Applegate <br />:. Group, t~~. <br />November.l9, 2003 <br />Division of Minerals and Geology <br />Department of Natural Resources <br />Attn: Ms.-Kate Pickford <br />1313 Sherman Street, Room 215 <br />Denver, Colorado 80203 <br />~iECEi~/ED <br />tdCiV 2 02003 <br />Oivisian of Minerals and Geoloa" <br />REs Respons®. to Adequacy Review Comments, 112(c) Construction Materisls TR-005, <br />Aggregate Industries -WCR, Inc., 83"d Joint Venture Pit, M-1992-069 <br />Dear Ms Pickford: <br />The following discussion and attachments are submitted on behalf of our client, City of Greeley, <br />and Aggregate Industries, WCR, Inc., in response to your adequacy review-comments received <br />for the 83'~ Joint Venture Pit. The Colorado Division of Minerals and Geology (D1v1G) <br />submitted supplemental adequacy review comments in a letter dated November 3, 2003. The <br />.information and discussion below addresses the comments presented by Allen Sorenson in his <br />letter dated October 31, 2003. . <br />As stated in the original adequacy review letter, the lake outfall channel was modeled in the <br />North Eagleview Regional Detention Pond, Concept Phase Report (March 2003) as being 10 feet <br />wide at an invert elevation of 4669 feet..The maximum flow in the channel is expected to be less <br />than 150 cubic feet per second (cfs) during the 100-year flood when the lake surface elevation is <br />at 4671.5 feet. Side slopes for the outlet channel will be graded at a minimum of 3H:1 V from <br />the 10-foot wide channel bottom to the top of slope. <br />The outlet channel will remain relatively flat from the created groundwater lake to the property <br />boundary and existing- channel under the railroad bridge. Flow velocities in the channel are <br />anticipated to be less than 5 feet per second. City of Greeley erosion protection guidelines <br />recommend vegetation cover to stabilize channel flows of less than 5 feet per second. <br />Erosion protection will be provided for the outlet channel during final reclamation. If possible, <br />the channel will be stabilized with a vegetative cover of native grasses consistent with the current <br />approved reclamation plan. Following initial grading of the slopes, topsoil will be replaced and <br />the area will be seeded. Reseeding of areas will be performed as necessary. <br />Alternatively; erosion protection for the outlet channel will be provided with hard armoring. If <br />sufficient vegetation cover cannot be established within the outlet channel, riprap, concrete <br />mattress, erosion fabric, or other appropriately designed erosion protection material will be used. <br />1499 West 120'" Avenue, Suite 200 ~- 5441 Boeing Drive, Suife 200 <br />Denver, Colorado 80234-2728 - ~ ~ vnva.applegategroup.com Loveland, Colorado 805:16-6855 <br />(303) 452-6611 • Fax (303) 452-2759 (970) 461-9884 • Fax (970) 6'13-1177 <br />