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V CIVIL RES"~URCES,LLC <br />~l 'G~ n~ <br />ENpINEE0.9fi pLANNER9 <br />May 3, 2005 <br />~olorado Department of Transportation <br />r. Joe Intermill <br />43379 Highway 51 <br />Ault, CO 80610 <br />RE: SW TKO Joint Venture, LLC, Division of Minerals and Geology Application M•2004.079 <br />Lupton Lakes Resource; CDOT Objection Letter- Wave Action Erosion ~ <br />Dear Mr. Intermill: <br />This letter is being written to present new and previously presented information regarding your concern with respect to <br />wave action erosion on the finished reservoir slopes that parallel Highway 85. Following is the excerpt from your letter <br />regarding the potential for wave action erosion: <br />CD07 Comment: The westem reclaimed shoreline in proximity to US Highway 85 is over one-half mile in length. <br />CDOT is concerned of wind and water erosion along the westem shoreline of the reclaimed pd. Please address the <br />effects of wind and water erosion around the reclaimed pond on all pond slopes. The applicant will need to provide <br />detailed designs of erosion control features such as rock armoring or other suitable measures. <br />Applicant Resaonse: Wave erosion on below grade water storage facilities does not jeopardize the stability of <br />surrounding property. We have asked for technical basis for this stated concern but none has been provided. In <br />summary, migrating lakes are undocumented to our knowledge and we don't believe this project will set new precedent. <br />The Lupton Lakes project has been reviewed by the State Engineers Office (SEO) Dam Safety Branch and has been <br />classified as anon-jurisdictional slope liner (Letter from Jack G. Byers, Deputy State Engineer, dated February 14, <br />2005). Even though no erosion protection is required for slope liners, we have proposed atwelve-foot wide (measured <br />horizontally) zone of erosion protection (Zone 2 as shown on the attached figure). The proposed finished geometry and <br />erosion protection are shown on Figure 1. <br />Zone twill be swell-graded mixture of: 213: sand, gravel, and cobbles left behind from mining <br />113: 6" of weathered claystone bedrock. <br />Following is a typical gradation specification for the Zone 2 material: <br />Sieve Size Percent Passino <br />7" 100 <br />1-112" 80-100 <br />No.4 35-55 <br />No. 200 17-30 <br />°No less than 80% passing the 1%"sieve. <br />°Unified Soils Classifcation: GC, GC-SC <br />This Zone 2 material has previously been approved by the SEO as a recognized erosion control measure for use <br />on slope liner portions of projects involving jurisdictional dams (Dunes Reservoir located at 112" Avenue and US <br />Highway 85; and South Platte Reservoir located adjacent to C-470 and S. Platte Canyon Road). Both of these projects <br />abut major highways including US Highway 85 and Highway C-470 and are being built with this Zone 2 erosion <br />protection. <br />451 OAK STREET, SUITE 209 • FREDERICK, COLORADO 80530 • PHONE: 303.833.1416 • FAX: 303.833.2850 <br />