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Function Completion Date Operators Minimum Streamflow Agreement Streamflow Releases Objective Information and Methods Used Reconmendations Streamflow Records Location Function Completion Date Operators Minimum Streamflow Agreement The reservoir stores water from the North Fork of the Colorado River and water pumped from Lake Granby. Water from Shadow Mountain Reservoir flows into Grand Lake at the northeastern end of the reservoir and subsequently is released into the Alva B. Tunnel, which conveys water across the Continental Divide to the eastern slope primarily for irrigation and power generation. Construction on the dam began in 1944 and was completed in 1946. Operations began in 1949 when other features of the Colorado-Big Thompson Project were completed. Bureau of Reclamation The BR adopted minimum flow releases from Shadow Mountain Reservoir around 1947. The minimum streamflow releases have been incorporated into the BR's operating criteria. The minimum flow releases from Shadow Mountain Reservoir into the Colorado River are 25 cfs October 1 through May 31, and 50 cfs June 1 through September 30. Recently, the BR has modified the flow regime by request from the CDWR to facilitate kokanee spawning. The modified flow regime is 20 cfs January through May, 50 cfs June through July, 40 cfs in August, 35 cfs September through October, and 45 cfs November through December, or the natural inflow, whichever is less. To maintain the downstream fishery and aquatic habitat, and more recently to facilitate kokanee spawning. The original flow regime, followed until just recently (1986), was based on changes in aquatic habitat conditions from 50 to 100 cfs. The aquatic habitat studies were conducted by the FWS in the late 1940's. The FWS reconmended the original flow releases in 1947. The BR accepted the flow release schedule with the added condition that if the inflow was less than the minimum flow amount, the outflow would equal the inflow. There are no streamflow records for the Colorado River imnediately below Shadow Mountain Dam. Granby Dam and Lake Granby Colorado River Basin Storage dam and reservoir are located on the Colorado River less than five miles downstream from Shadow Mountain Dam, near Granby in Grand County, Colorado. Lake Granby is the primary storage facility on the west slope. Water from the Colorado River is stored in Lake Granby and then pumped into Shadow Mountain Lake. Water from Lake Granby is primarily used for irrigation and power generation on the eastern slope. Water was initially stored in the fall of 1949, but the dam was not completed until 1950. The Granby Pump, used to pump water into Shadow Mountain, was also completed in 1950. Bureau of Reclamation An interim minimum flow release schedule was proposed by the BR and accepted by the Secretary of the Interior in 1951. The minimum flow schedule was permanently adopted in 1961, and subsequently incorporated into the BR's operating criteria for the Colorado-Big Thompson Project. 8