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The River of the West
From its headwaters high in the Wind River Mountains of Wyoming, the Colorado meanders 1,400 miles and is the sole dependable water supply for 244,000 square miles, an area embracing parts of seven western states (Wyoming, Colorado, Utah, New Mexico, Nevada, Arizona, California) and Mexico.
Though the watershed is vast, the Colorado is not a heavy flowing stream, ranking about sixth among the nation's rivers and having an average annual volume of less than fifteen million acre-feet. This is only a thirty-third that of the Mississippi and a twelfth that of the Columbia, but this modest flow became in the twentieth century the most disputed body of water in the country and probably in the world.
Colorado River - Background
Information Droplets
The Colorado River watershed drains 244,000 square miles, 2000 in Mexico.
Twenty-five million people in seven western states (Arizona, California, Colorado, New Mexico, Nevada, Utah, and Wyoming), two Mexican states (Sonora and Baja California), and 32 American Indian tribal communities share Colorado River water; 30 million people receive electricity from its hydroelectric power.
The river flows 1,700 miles from Wyoming’s melting glaciers and Colorado’s snow run-off and falls 14,000 feet before reaching its natural outlet, the Gulf of California
There are 34 Indian tribes in the basin, 27 claim rights to use it.
Ten tribes occupy Indian reservations with rights to the Colorado River
The 1922 compact divided the river into two basins that get half the water flow: the upper basin includes New Mexico, Wyoming, Colorado, and Utah and the lower basin includes Arizona, California, and Nevada.
Every drop of its 5 trillion gallons of water flow is apportioned
Human use of Colorado River water has approximately doubled its salinity
Arizona’s share of the Colorado River enabled large population increases in Phoenix and Tucson, which would otherwise not be able to exist
There are over 10 major dams and 80 major diversions on the river that collectively prevent the river from reaching the Delta exceed in high flow years
The Hoover Dam, at 726 feet, flooded 115 miles of the Colorado River and created Lake Mead
The prior appropriation doctrine of 1855 is still in force, which grants oldest water rights superiority over junior users so long as water is put to a beneficial use
In 1905 levees on the Colorado and Gila River broke and water flooded for two years, creating the Salton Sea, which is 45 miles long, 17 miles wide and 80 feet deep
Cocopa Indians along the US/Mexico border, who have depended on the river for 2,000 years, must now truck in their water because upstream conditions prevent the river from flowing to their communities
As dams began to control the river it carried less silt and more salt. Salinity tripled between 1917 and 1961
By 1964, 19 big dams controlled the river
There are more than 20 storage reservoirs with capacities greater than 20,000 acre-feet in the Colorado River Basin
The two largest reservoirs are Lake Mead and Lake Powell (25.88 million and 24.32 million acre-feet respectively)
The Delta is the largest remaining wetland system in the American southwest
River flows to the Delta have been reduced nearly 75 percent during the 20th century. Consequences: less silt, fewer nutrients, higher salinity, higher concentrations of pollutants
Colorado River Compact
The bill of rights that allocates the river's resources was created, largely, with the 1922 Colorado River Compact. The language and results of the Compact negotiations speak to us today about how society in the 1920s, as represented by seven commissioners (one each from Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming), and Herbert Hoover, U.S. Secretary of Commerce, conceived of how to divide the waters. Based on erroneous estimations of total river flow, and of course not taking into account the explosive growth in some of the then less populated states, the Compact allocated water to the Upper and Lower Basins with the dividing point at Lee's Ferry...
The negotiations are remarkable for what they did not consider. The commissioners parsed the waters without Native American representation and with only a hint at Mexico's rights, telling us something about the political and social climate in the early 1920s.
Source: Moving Waters
The Colorado River Compact divides the Colorado River into Upper and Lower Basins with the division being at Lee Ferry on the Colorado River one mile below the Paria River in Arizona. The Lower Basin states are Arizona, California, and Nevada, with small portions of New Mexico and Utah that are tributary to the Colorado River below Lee Ferry. The Upper Basin states are Colorado, New Mexico, Utah, and Wyoming, with a small portion of Arizona tributary to the Colorado River above Lee Ferry.
Article III of the Compact apportions the waters of the Colorado River to the Upper and Lower Basins as follows:
The Compact apportions the right to exclusive beneficial consumptive use of 7.5 million acre-feet of water from the "Colorado River System" in perpetuity to the Upper Basin and the Lower Basin. It allows an additional 1.0 million acre-feet per year of increased beneficial consumptive use to the Lower Basin.
Source: Water Knowledge - Colorado State University
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