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COLORADO RIVER DELTA BI-NATIONAL SYMPOSIUM PROCEEDINGS ENGLISH 32 PANEL II: CONVEYANCE SYSTEMS CONVEYANCE SYSTEMS AND INFRASTRUCTURE IN THE COLORADO RIVER BASIN IN THE UNITED STATES TOM RYAN UoSo BUREAU OF RECLAMATION, UPPER COLORADO REGION: Mr. Ryan provided and overview of the water resources in the Upper Basin, including the natural hydrologic system. The Upper Basin is about 113,000 square miles and slightly less in area than the Lower Basin. The region has a varied topography with eleva- tions ranging from 1,000 meters at Lees Ferry to over 4,000 meters in the mountainous headwa- ters. The river originates in Rocky Mountain National Park and is fed by a number of tribu- taries throughout the Upper Basin including the largest, the Green River. Climates vary and some areas receive over 100 centimeters of rain while other receive less than 20. April through July is considered the runoff period, contributing about 70 percent of the annual runoff for the basin. In the Colorado River basin there are, hydro- logically speaking, both wet and dry periods. Based on flow measurements at Lees Ferry, it was abnormally wet the first part of the century, followed by a drying period in the '30s with a critical period starting in 1953 that brought the 12 driest consecutive years on record. The early to mid-'80s were wet followed by dry years in the late '80s and early '90s. The current rate of depletion from the river that is taking place in the Upper Basin is ap- proximately 4.7 million acre-feet including reservoir evaporation. There are about 50 Reclamation reservoirs - more than in the Lower Basin but smaller in size ~ with over 30 million acre-feet of water in storage. There are 1.6 million acres of irrigated land and most of the water in the Upper Basin is used towards agriculture. Many of the projects are relatively small and use water from Reclamation facilities that are operated by local water districts. Water from the Upper Colorado River Basin also serves major cities such as Denver, Albu- querque and Salt Lake City. The most significant project in the Upper Basin is the Colorado River Storage Project authorized in 1956 under the Colorado River Storage Project Act and operated by the Bureau. It authorized construction of Glen Canyon Dam, Flaming Gorge Dam, the Aspinal units - a series of three dams (Blue Mesa, Morrow Point and Crystal reservoirs) and Navajo Dam on the San Juan. Lake Powell (behind Glen Canyon Dam) is operated consistent with the 1970 coordinated long-range operating criteria. Lake Powell serves as the pool of water at the end of the Upper Basin to assure deliveries required under the compact reach the Lower Basin. The operat- ing criteria include 3 modes that govern releases from the dam. There is a minimum release of 8.23 million acre-feet to meet downstream demands. There are equalization releases to balance the amounts of water in Lake Powell and Lake Mead, though under certain condi- tions, equalization releases are not made. Additionally, spill avoidance is practiced whereby if high inflows are expected, water is released prematurely in order to create storage space. There are endangered species recovery programs in place in the Colorado River and San