Colorado River Basin Graphs, 1922

Colorado River Basin Graphs, 1922

In 1922, the Colorado River Compact divided the waters of the Colorado River among seven states. This chart was used to estimate irrigation and other water requirements of the American West. The waters were divided at Lee's Ferry in Arizona into the upper and lower basins.

Note that the water apportioned in the Compact was done in specific numbers of acre-feet, rather than as percentages of water flowing down the river annually.  This fact continues to impact us today.  While the negotiators of the Colorado River Compact were aware of a severe drought in 1902, they still assumed that a specific number of acre feet would be coming down the Colorado.  The number they chose turned out to be the highest annual flow rate in approximately 14 million years.  The river has not had that much water in it since then.  

This is why, today, the subject of renegotiating the original Colorado River Compact keeps coming up, and is so contentious.

Map courtesy of the Honorable Greg Hobbs Collection

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