Colorado River Compact An agreement entered into on November 24, 1922 and ratified by the legislatures of the seven states within the Colorado River Basin Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming agreeing to the general allocation of the waters of the Colorado River. The compact divided the Colorado River Basin into an Upper Basin and a Lower Basin, with the division point established at Lees Ferry, a point in the mainstream of the Colorado River approximately 30 river miles south of the Utah-Arizona boundary. The Upper Basin was defined to include those parts of the states of Arizona, Colorado, New Mexico, Utah, and Wyoming within and from which waters naturally drain into the Colorado River system above Lees Ferry, and all parts of these states that are not part of the river’s drainage system but may benefit from water diverted from the system above Lees Ferry. The Lower Basin was defined to include those parts of the states of Arizona, California, Nevada, New Mexico, and Utah within and from which waters naturally drain into the Colorado River system below Lees Ferry, and all parts of these states that are not part of the river’s drainage system but may benefit from water diverted from the system below Lees Ferry. The compact did not apportion water to any state, however, it did apportion to each upper and lower basin the exclusive, beneficial consumptive use of 7,500,000 acre-feet of water per year from the Colorado River system in perpetuity. Further, the compact gave to the Lower Basin the right to increase its annual beneficial consumptive use of such water by 1,000,000 acre-feet. This compact cleared the way for federal legislation for the construction of Hoover Dam. Subsequently, the Upper Basin states entered into the Upper Colorado River Basin Compact on October 11, 1948 which provided Arizona to use 50,000 acre-feet of water per year from the upper Colorado River system and apportioned the remaining water to the Upper Basin states according to the following percentages: Colorado, 51.75 percent, New Mexico, 11.25 percent, Utah, 23 percent, and Wyoming, 14 percent. The Lower Basin states could not come to an agreement on apportionment on their own, and in October 1962, the U.S. Supreme Court ruled that of the first 7,500,000 acre-feet of mainstream water in the Lower Basin, California is entitled to 4,400,000 acre-feet (58.67 percent), Arizona to 2,800,000 acre- feet (37.33 percent), and Nevada to 300,000 acre-feet (4.00 percent).