by Greg Walcher, E&E Legal Senior Policy Fellow
As appearing in the Daily Sentinel

Several recent newspaper articles have focused on the Colorado River, because of the historically low water levels in Lake Powell and Lake Mead. A recent follow-up in Greenwire asked the rhetorical question, “Could the Colorado River Compact adapt to go with the flow?”

The question was only rhetorical, but should it be? Actually, water leaders in all the states downstream from Colorado have been hinting at that idea for years. That’s because they all want more water than they are entitled to, under the 1922 Interstate Compact that determines how much water is allocated for each state. A brief refresher course on that Compact helps illuminate the issue.

In the 1922 Compact, Colorado River water was divided equally between Upper and Lower Basins, based on an annual flow of about 15 million acre-feet (MAF), the historical average at the time. The Lower Basin states of California, Nevada and Arizona were allocated 7.5 MAF of water, as were the Upper Basin states of Colorado, Wyoming, Utah and New Mexico. California convinced Congress to distribute the Lower Basin’s half by population: 4.4 MAF for California, 2.8 MAF for Arizona, and 0.3 MAF for Nevada. The Upper Basin states agreed on distribution of their half in 1948, allocating percentages of the annual flow, not fixed amounts. Colorado got 51.75% (of the Upper Basin half), Utah 23%, Wyoming 14%, and New Mexico 11.25%.

For decades, California grew faster, using all its share, along with unused portions of the other states’ shares. California also opposed virtually every attempt by the other states to develop their entitled water. Colorado still uses roughly a million acre feet less than its legal share, despite frequent water shortages.