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<br />Water Supply Reserve Account - Grant and Loan Program <br />Water Activity Summary Sheet <br /> <br />Applicant: Hinsdale County and the Upper <br />Gunnison River Water Conservancy District <br /> <br />Water Activity Name: Lal(e San Cristobal <br />Control Outlet Structure Project <br /> <br />Water Activity Purpose: Technical Analysis <br />regarding permitting feasibility study <br />/Environmental Compliance (see <br />Issues/Additional needs discussion) <br /> <br />Amount Requested: $35,000.00 <br /> <br />Source of Funds: Basin <br /> <br />Matching Funds: None <br /> <br />County: Hinsdale <br />Drainage Basin: Gunnison River <br />Water Source: Lal(e Forl( Gunnison River <br /> <br />Water Activity Summary: <br /> <br />Hinsdale County and the Upper Gunnison River Water Conservancy District (UGRWCD) are examining the <br />feasibility of constructing a new permanent control structure at the outlet of Lal(e San Cistobal. The control <br />structure would regulate the lal(e level to provide releases of water from the lal(e and prevent failure of the <br />lal(e outlet structure during flood events. The stored water resulting from this project will be used primarily <br />as augmentation water within the Lal(e Forl( of the Gunnison River. Other beneficial uses may include <br />agriculture, recreation and possibly releases for instream flow purposes. <br /> <br />The feasibility study will consist of two analyses that will be performed simultaneously: <br /> <br />1. Estimate the firm yield of the 960 acre-feet of storage and develop an engineering report to support <br />the water right application in case no. 03CWI08 and, <br />2. Analyze the current and future marl(et for water impounded by the structure. <br /> <br />According to the application, in 2003, a feasibility study was conducted to examine the potential enlargement <br />of Lal(e San Cristobal. This study stated that in the 1950s the lal(e was altered from its natural condition <br />when the Hinsdale County Road and Bridge Department constructed a rocl( and timber dam at the outlet. <br />Two significant issues were made apparent in this study. First, there were significant wetlands on the <br />perimeter of the lal(e which would be inundated by the proposed enlargement. The mitigation of these <br />wetlands appeared to be cost-prohibitive for the project. In addition, the Colorado Water Conservation <br />Board holds a Natural Lal(e Level (NLL) water right on Lal(e San Cristobal (4-77W3366) with an <br />appropriation date of May 12, 1976 with an elevation of 8995.0 feet. After further investigation, it was <br />determined that the dam constructed in the 1950s raised the lal(e elevation to 8992.5 feet from its natural <br />elevation of 8990.0 feet. Based on these findings, the applicants believe that the NLL on Lal(e San Cristobal <br />is incorrect and should be modified pursuant to Rule 9c (1) of the Rules Concerning the Colorado Instream <br />Flow and Natural Lal(e Level Program. It should be noted that in 2003, the Upper Gunnison River Water <br />Conservancy District claimed the additional 960 acre-feet impounded by the dam in water right application <br /> <br />1 <br />