Gunnison - Lake San Cristobal Outlet Mod Project Phase II_Water Activity Summary

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Water Supply Reserve Account -Grant and Loan Program Water Activity Summary Sheet Applicant: Upper Gumlison River Water Conservancy District Amount Requested: $75,265 Water Activity Name: Lake San Cristobal Outlet Modification Project Source of Funds: Gunnison Basin Account Matching Funds: None specified Water Activity Purpose: Study and/or Analysis of a Structural Project County: Hinsdale County Drainage Basin: Gunnison River Water Source: Lake Fork of the Gumlison River Staff Recommendation Staff recommends approval of up to $75,265 from the Guiulison Basin Account to help complete the Lake San Cristobal Outlet Modification study contingent on resolution of the item in the issues/additional needs section. Water Activity Summary: The Lake San Cristobal Outlet Modification Project is intended to replace an annually-placed rock wall with a permanent outlet stn~cture. This structure ~~ ould maintain the same storage regime that has taken place at the lake for over 50 Years. The proposed outlet ~yould allow for more controlled releases from the lake while eliminating the need to place and remove rocks on an annual basis at the lake's outlet. In addition, the ne~y outlet stn~cture would alloy development of a local plan of augmentation that would benefit the enyiromnent along the Lake Fork of the Gunnison and reduce the reliance on Blue Mesa Reservoir as a downstream source of augmentation water. This project is necessary to provide ahigh-altitude local source of augmentation ~yater that ~yill improve ~yater availability for the Instream Floe- Right on the Lake Fork. The stream below Lake San Cristobal «ould receive flo«s fi-om storage at times ~yhen the stream levels are belo~y the ISF right, thus improving the habitat for fish and other species along the Lake Fork from Lake San Cristobal to Blue Mesa Reservoir. The three entities involved in this project, Hinsdale Counter, To~~n of Lake City-, Ind the Upper Gunnison River Water Conservancy District. are worknig cooperatively- to meet the needs of their constituents in the Lake Fork drainage. The three applicants have each contributed $10,000 to begin «ork on Phase I of the design. Phase I includes prelilninai-~- suive~-ing and a 6~% design incorporating a hazard classification report and initial hydrology- and hydraulic analyses. The applied-for $75,265 grant ~yill allow continuation of the design ~york. Previous Studies "Feasibility Study, Controlled Outlet Structure, Lake San Cristobal, Hinsdale County, Colorado", by URS Corporation, 2004. A copy of this report was previously provided to CWCB. This study evaluated the concept of constructing a new permanent outlet control structure on Lake San Cristobal It proposed that a new stn~cture would consist of a steel sheetpile cutoff structure and buried