Expert Report of D. Randolph Seahom and Exhibits

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4 Consumptive Uses and Losses is Irrigation consumptive use accounts for about 55 percent of the water use in the Upper Main Stem reporting area exclusive of any share of main stem evaporation. In an average year approximately 540,000 acres of land are irrigated. Approximately, 28 percent of the water consumptively used is exported to serve agricultural and municipal needs on the Eastern slope of the Continental Divide in Colorado. San Juan - Colorado (Colorado -New Mexico - Utah - Arizona) The San Juan reporting area is drained by the Colorado River and its tributaries below the mouth of the Green River and above Lee Ferry, Arizona. The largest of the tributary streams is the San Juan River which heads on the western slope of the Continental Divide in southwestern Colorado. Principal tributaries of the San Juan River are the Navajo, Piedra, Los Pinos, Animas, and La Plata Rivers. The other main tributaries in the basin are the Dirty Devil, Escalante, and Paria Rivers, which drain a portion of the Eastern slope of the Wasatch Plateau in Utah. The reporting area includes about 38,600 square miles in portions of Utah, New Mexico, Arizona, and Colorado. The largest towns are Durango and Cortez in Colorado, Monticello and Blanding in Utah, Farmington in New Mexico, and Page in Arizona. Mining and agriculture form the economic base for the San Juan - Colorado reporting area. The agricultural development is similar to that of the Upper Main Stem where most of the 40 cropland is devoted to livestock feeds except for the production of diversified market crops on lands with favorable air drainage. The main market crops are fruit, vegetables, and dry beans. Oil, natural gas, and coal are the most important minerals produced. Thermal electric power production is increasingly important to the economy of the area. Irrigation accounts for the largest use of water, about 85 percent of the San Juan reporting area use, exclusive of any share of main stem evaporation. About 310,000 acres of land are irrigated in an average year. Lower Colorado River Basin Main Stem Below Lee Ferry, Arizona - California- Nevada The Colorado River has a length of more than 700 miles and a drainage area of 132,300 square miles within the Lower Colorado River System in the United States. The dividing point between the Upper and Lower Basin is Lee Ferry. Diversions are made at Lake Mead to the rapidly expanding North Las Vegas -Las Vegas- Henderson - Boulder City area for municipal and industrial purposes. The river below Lake Mead courses through canyons and broad alluvial valleys interspersed with bordering groups of mountains. Lakes Mohave and Havasu provide flood control and regulatory storage below Lake Mead. Lake Mohave reregulates Hoover Dam releases for power production and for deliveries to mexico. Lake Havasu also provides a forebay for pumped diversions to the Central Arizona Project (CAP) in Arizona and export to the Metropolitan Water District of Southern California.