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<br />OOl~B~ <br /> <br />. <br /> <br />. <br /> <br />Draft Task 7 Technical Memorandum <br /> <br />Commission permit, a minimum release from Stagecoach of 20 cfs from August I through <br />November 30 and the minimum of 40 cfs or the natural inflow from December I through July <br />31, was enforced in the model. <br /> <br />Stagecoach Reservoir was modeled so that an average drawdown of 10 to 12 feet occurs <br />during the fall and winter months. This translates to approximately 7,000 af if the drawdown <br />is initiated when the reservoir is full. This was done in order to generate power, accommodate <br />spring inflows, and avoid reservoir spills. <br /> <br />Steamboat Lake, owned and operated by the Colorado Division of Parks (CDOP), was <br />modeled with three storage pools including: <br /> <br />. 5,000 af Colorado Ute (Tri-State) <br />. 3,311 af augmentation flow <br />. 18,068 af recreation pool (minimum pool) <br /> <br />Water from the Colorado Ute account in Steamboat Lake has never been used in the past <br />and is available to serve only the Hayden Station water requirements. The recreation pool in <br />Steamboat Lake was modeled as inaccessible to any demands. This was done in order to <br />reflect intentions of the Colorado Division of Parks to maximize recreational opportunities at <br />the lake. <br /> <br />The 3,311 af USFWS pool at Steamboat Lake was used in the model to augment flows <br />in the Yampa River during the months of August and September (approximately 27 cfs). After <br />this water is released from Steamboat Lake it is unavailable for diversion by downstream <br />demands on the mainstem of the Yampa River. This water is effectively shepherded <br />downstream to the eastern edge of Dinosaur National Monument. <br /> <br />Steamboat Lake was modeled with an outlet capacity of 450 cfs and has no power <br />generating facilities. There are several instreani flow filings on the Elk River and Willow <br />Creek below Steamboat Lake. These filings are for between I and 7 cfs and have <br />appropriations dates in 1977. These instream filings were not represented in the model and <br />except for the release of water, the reservoir was operated on an fill and spill basis. <br /> <br />Elkhead Reservoir currently has two contracts for storage. Colorado Ute has a contract <br />for 8,310 affor use as a backup cooling water supply for the Craig Station. The remaining <br />5,390 af is committed to the Colorado Division of Wildlife for recreational purposes. <br />However, the CDOW ownership is currently in the process of being purchased by the City of <br />Craig. For purposes of this study, it was assumed that this transfer will be completed and that <br />this storage will be available to certain downstream demands. The modeled allocation of active <br />and inactive storage in Elkhead Reservoir was as follows: <br /> <br />. 8,310 af Colorado Ute (Tri-State) <br />. 1,668 af municipal and industrial <br />. 3,722 af minimum pool (dead storage) <br /> <br />There are no instream flow filings on Elkhead Creek below the reservoir and no known <br />minimum release requirements. The existing Elkhead Reservoir outlet capacity is 165 cfs. <br />There are no power generating facilities. <br /> <br />Model reservoirs and demands were ranked so as to follow a specific protocol for access <br />to storage supplies by basin demands. As currently modeled, municipal and industrial (M&I) <br />demands at Craig have access only to 1,668 af of Elkhead Reservoir storage. M&I demands at <br />Hayden and Steamboat have access to 4,000 af from Stagecoach Reservoir. M&I demands at <br /> <br />8 <br /> <br />, . <br /> <br />;1:,",& <br />