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I Ie I I I I I I I .. I I I I I I -. I h ,'';''l;:-~'', Section 2.0 EXISTING CONDITIONS 2.1 Canal system descriotion The estimation of physically available supplies for the proposed project requires an assessment of how flows are currently being used. This assessment requires the creation of mathematical models which simulate current and proposed UVRP system operation. The models are based upon a period of record of 32 years beginning in January, 1952. This section describes the major canals and other waterways within the UVRP which would be affected by development. Historic water patterns are presented, and the water budget model used to describe these patterns is described. Input and output data required for the existing conditions are also defined in this section. The proposed development would be located within the boundaries of the UVRP, which supplies irrigation water to nearly 86,000 acres of land. The canal system and irrigated lands begin about six miles south of Montrose and extend downstream (northward) for 34 miles along both sides of the Uncompahgre River, completely surrounding the cities of Montrose, Olathe, and Delta. Figure 2.1 shows the location of the canals and the UVRP boundaries with respect to major features of the area. The area is characterized by low annual precipitation (less than 9 inches at Montrose), low humidity, and a wide range of annual and daily temperatures. Irrigated crops include small grains, alfalfa, corn, broccoli and onions. Cherry and apple orchards are also present in the northern portion of the area. Population in the area is sparse; only 24,300 people live in Montrose County and 21,200 people live in Delta County. The UVRP is one of the oldest reclamation projects in the United States and one of the first built under the authority of the Reclamation act of 1902. In addition to irrigation water, the UVRP supplies water for stock use and for three cities (Montrose, Olathe and Delta) and four rural water districts. The UVRP is owned by Reclamation and has been operated by the UVWUA since 1932. Irrigation and water supply demands are met by diverting flows from the Gunnison and Uncompahgre Rivers (see Figure 2.1). The UVWUA holds senior water rights in both the Gunnison and Uncompahgre Rivers. Historically, about 505,000 acre-feet of water annually flow into the Uncompahgre Valley. About two-thirds of this flow is supplied by the Gunnison River. The remaining supplies are diverted from the Uncompahgre River, which jOins the Gunnison River near Delta (see Figure 2.2). - 2.1 -