2003-08-15_REVISION - M1977534 - Laserfiche WebLink

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Ms. Jacoby August 13, 2003 Page 3 of 4 From a regulatory standpoint, a Flood Insurance Study in Clear Creek County was prepared in 1976 by Black & Veatch Consulting Engineers, for the U.S. Department of Housing and Urban Development. We have reviewed this study and found that the 100-year flood below Lion Creek, which joins West Fork Clear Creek in the Town of Empire about 0.8 mile downstream of the confluence between West Fork Clear Creek and Mad Creek, was estimated to be 775 cfs. The regulatory flood flow is lower than the statistically developed 100-year flood flow used in our design evaluations. In conclusion, Wheeler's design analysis, which is based on higher flood flows than were used to define the regulatory floodplain, demonstrate that the constructed flood levee will not impact the 100-year floodplain adjacent to the flood levee or downstream of the project in the Town of Empire. Item 3 - In response to Jefferson Conservation District's comments about their desire to use native species whenever possible, we would be willing to amend the reclamation specification to use a Colorado Native Mix that would be applied at a broadcast seeding rate of 15 pounds per acre. Please be advised that the SEO has reviewed and approved the plans and specifications for the construction of Guanella Dam. Any changes to the approved specifications, including the previously approved seed mix, must be approved by the SEO. A copy of the approved reclamation specification is attached for your information. If acceptable to the DMG, we would propose to submit the following seed mix to the SEO for approval: 20% Western Wheatgrass 20% Slender Wheatgrass 15% Blue Grama 15% Buffalograss 15% Sodar Streambank Wheatgrass 10% Sherman Big Bluegrass 5% Canada Wildrye If the DMG or the Jefferson Conservation District has a specific seed mix that is preferred for this site, we would also be happy to consider it.