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<br />on:.4S3 <br /> <br />, ., <br /> <br />The DWCD administers the Dolores Project within its administrative boundaries and the Ute <br />Mountain Ute Indian Tribe administers project facilities serving their reservation. Reclamation, <br />the Forest Service, Bureau of Land Management, and Colorado Division of Wildlife participate <br />in managing recreational, fish and wildlife, and cultural resource aspects of the Dolores Project. <br /> <br />Hvdrolol!V. Streamflows. and Water Ouality <br /> <br />The Dolores River and McEImo Creek are the primary waterways in the area. Prior to <br />development, these streams were characteristic of many western watersheds with high spring <br />flows from melting snowpack and low summer, fall, and winter flows. Both streams have been <br />extensively developed for irrigation and other uses over the last 100 years. <br /> <br />The Dolores River originates in the LaPlata and San Juan Mountains and flows north to the <br />Colorado River near Cisco, Utah. The average annual inflow to McPhee Reservoir is roughly <br />350,000 acre-feet. For most of the last century prior to construction of McPhee Dam, the MVIe <br />diversion structure near the town of Dolores diverted an average of about 130,000 acre-feet <br />annually (maximum diversion of 153,400 acre-feet annually) from the Dolores River to the <br />Montezuma Valley which is in the San Juan River drainage. Water shortages were often severe <br />during late summer and fall irrigation seasons. The Dolores River occasionally went dry below <br />the diversion in late summer and fall, greatly limiting the fishery (Reclamation, 1977). <br /> <br />MVIC diversions from the Dolores River have taken place since 1886 with the diverted amount <br />varying with the available flow in the Dolores River. The 6,000-8,000 acre-feet being considered <br />for the Carriage Contract was diverted from the Dolores River basin from the late 1880's until at <br />least 1990 when it was needed and available and also was diverted at least 3 times in the past 10 <br />years. For purposes of this EA, it is assumed the 6,000-8,000 acre-feet has been diverted from <br />the Dolores River into the San Juan Basin because that is the condition that occurred in at least <br />110 of the past 120 years. <br /> <br />Most of the irrigation lands in the area are in the San Juan River drainage. Return flows from <br />irrigated fields flow into the San Juan drainage and enhance the flow of that river for its last 100 <br />miles. In the San Juan drainage, the subject 6,000-8,000 acre-feet has historically been used and <br />reused for irrigation. How much of this was historically depleted is unknown, but estimates <br />range up to 85 percent. <br /> <br />The completion of McPhee Dam allowed storage of spring runoff, regulation of flows, and <br />provided Dolores Project water to maintain a base flow downstream from the dam. Initially the <br />base flow was determined by specific release criteria (78,50, or 20 cubic-feet per second [cfs] <br />dependent on the water supply situation). This plan has been modified by creating a managed <br />pool of water available from storage for downstream releases for the tailwater trout fishery and <br />other resources (Reclamation, 1996). The managed pool consists of 25,400 acre-feet of water <br />originally allocated from the Dolores Project water supply plus 3,900 acre-feet of water <br />purchased from the DWCD by Reclamation for a total allocation of29,300 acre-feet. Up to <br />3,900 acre-feet of water is also provided for downstream senior water rights; however, this water <br /> <br />8 <br />