“Water in the West” from an admitted novice

By Michelle Truly

(Editor’s Note: This is the second part of a three-part series exploring some of the ins and outs, whys and hows of water regulation that impacts everyone in the valley….)

Part II – The Colorado River Compact

After the Lewis and Clark expedition in the early 1800s explored and mapped the region west of the Mississippi River, a flow of people escaping the hot, dirty eastern cities started heading west. This migration was accelerated by the Homestead Act of 1862 that gave each head of household 160 acres of land to live on, build a home and cultivate to attain ownership of that land. 

But the early homesteaders found that most of the western arid land was difficult to cultivate due to the lack of rainfall. Fortunately, the Mormons who had settled in Utah had experience in irrigation, and showed that a system of water collection and distribution through ditches and canals could solve this problem. So, thank the Church of Latter-Day Saints for being kicked out of Illinois and for setting up the West for an even larger population!

As the population grew and the demand for irrigation water increased, local, state and federal laws and policies were enacted to keep neighbor from fighting neighbor over water.

One of the largest Western water policies put in place was the Colorado River Compact of 1922 that defined how the river would be divided up as it flows southwest through seven states. This short six-page agreement divided up the Colorado River flow into two basins and that would split the flow in equal portions. The Upper Basin consists of Colorado, Utah, New Mexico and Wyoming, and the Lower Basin consists of Arizona, Nevada and California. Things seemed to work pretty well for a while until consumption increased and drought years hit. 

It turns out that there was a big “oops” in the calculation of the average annual river flow that was used when the compact was written. In 1922, the compact used an average river flow calculation that was based on the previous years which were unusually wet years. The actual river flow over a longer period of time is actually approximately 30% less than what the compact assumed. So instead of sharing 17.5-million-acre feet (maf) of water each year, the seven states are sharing approximately 12 million (maf) of water.  So, you would think that everyone should get a 30% decrease in their share, but it is not that simple. Everyone wants the actual water amount cited in the compact – period. So, we have a problem. 

Written by Michelle Truly, a Crested Butte resident and retired aerospace engineer, who readily admits that she has no business writing about water in the west but is fascinated by the subject.