FIGURE 1-2 Average annual precipitation in the United States, 1971-2000.

SOURCE: http://www.ocs.orst.edu/prism/products/matrix.phtml?vartype=ppt&view=maps.

capacities of roughly 28 and 27 million acre-feet, including dead storage, each of these reservoirs is capable of storing roughly 2 years of the river’s annual mean flow. Storage levels and available capacity of Lake Mead and Lake Powell are particularly important in guiding how the Bureau of Reclamation releases flow through the Colorado River system. Other major facilities and projects within the basin include Flaming Gorge Dam in Wyoming, the Colorado-Big Thompson Project, the Central Utah Project, the Aspinall Unit (which includes Blue Mesa, Crystal, and Morrow Point dams) on the Gunnison River in Colorado, Navajo Dam in New Mexico, the Central Arizona Project’s Hayden-Rhodes Aqueduct, the Salt River Project in Arizona, Parker Dam and the Metropolitan Water District of Southern California’s Colorado River Aqueduct, Imperial Dam and the All-American Canal serving the Imperial Valley in southern California, and Morelos Dam immediately south of the Mexico-U.S. border. These projects are designed to provide water to users both within and beyond the Colorado River basin, including much of southern California, Colorado’s Front Range cities, and the City of Albuquerque.