Expert Report of D. Randolph Seahom and Exhibits

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• 2 Consumptive Uses and Losses consultation with the States of the Lower Basin individually and with the Upper Colorado River Commission, and shall be transmitted to the President, the Congress, and to the Governors of each State signatory to the Colorado River Compact. PLAN OF STUDY The Plan of Study and Methods Manual for the Colorado River System Consumptive Uses and Losses Report 1985 -1990 was prepared and submitted in July 1992. These procedures were generally followed in the preparation of this report. Any changes in methodology are presented in the Methodology and Data Adequacy section of this report. STUDY REPORTING AREAS The drainage area of the Colorado River System in the United States is approximately 242,000 square miles. The river originates in the Rocky Mountains of Colorado and Wyoming, flows southwest about 1,400 miles, and terminates in the Gulf of California. The system consists of portions of seven states: Arizona, California, Colorado, New Mexico, Nevada, Utah, and Wyoming. The drainage area was divided into nine subbasins for the purposes of this report. The Colorado River Compact, signed November 24, 1922, was established because the Upper Basin States were concerned that any storage on the river would be put to use more rapidly by the Lower Basin States, thus allowing them to claim prior appropriative rights. The Upper Basin States wanted provisions for their future development. The term "Upper Basin States" refers to the States of Colorado, New Mexico, Utah, and Wyoming. "Lower Basin States" refers to the States of Arizona, California, and Nevada. However, the Upper Colorado River Basin refers to the hydrologic boundaries. Lee Ferry is the division point between the Upper Colorado River Basin and the Lower Colorado River Basin. Therefore, the hydrologic boundaries include portions of Arizona in the Upper Colorado River Basins and portions of Utah and New Mexico in the Lower Colorado River Basin. Hydrologic boundaries are shown on the map on page ii. The major tributary streams selected as reporting areas in the Upper Colorado River Basin are: Green River (Wyoming, Colorado, Utah), Upper Main Stem (Colorado, Utah), and San Juan - Colorado (Colorado, New Mexico, Utah, Arizona). Five tributary areas in addition to the main stem were selected in the Lower Colorado River Basin: Little Colorado River (Arizona, New Mexico), Virgin River (Utah, Arizona), Muddy River (Nevada), Bill Williams River (Arizona), Gila River (Arizona, New Mexico), and remaining areas in Arizona, Nevada, and Utah. The outflow point and drainage area for each is shown in table C -1. The boundaries of the reporting areas are shown on the map on page ii. A brief description of each reporting area follows.