By Linn Smith

“It is the most contested, played-upon, silt-laden, diverted, engineered, dammed, stored (four times its volume and one-fifth of its length is held in reservoirs), farmed with, and metro-dependent river in America.” – The Colorado River: Flowing Through Conflict

June 20, 2015—Running more than 1,450 miles from Colorado to Mexico, the Colorado River and its tributaries provide more than 33 million people with water. Colorado, Utah, New Mexico, Arizona, Nevada, Wyoming and California depend on this river. The river also generates hydroelectric power, which supplies electricity to Nevada, Arizona and California. Over 250,000 people are employed in various jobs related to the river, and recreational activities account for millions of dollars in revenue.

The Law of the River

According to Coloradoriverbasin.org, ““The Colorado River is managed and operated under numerous compacts, federal laws, court decisions and decrees, contracts, and regulatory guidelines collectively known as the ‘Law of the River.’ This collection of documents apportions the water and regulates the use and management of the Colorado River among the seven basin states and Mexico. The Colorado River Compact of 1922 is the cornerstone of the Law of the River.”

When the Colorado River Compact was written in the 1920’s, tree rings showed these years to be some of the wettest in more than 500 years. These wet years led to an abundance of water,
which allowed the “Law of the River” to allocate more water to users than the river currently has to offer. This, plus the ongoing drought, has lead to the worst case scenario for the Colorado River–it’s drying up!

Overuse of the Colorado River

In the past, the river continued to the Pacific Ocean. Today, it dries up in Mexico, because most of the water in the Colorado River has been diverted to farms and cities in the Southwestern United States. Only a small channel of the river makes it across the border to Mexico and that channel hasn’t made it to the Gulf of California (100 miles away) since 1993, when intense rains lead to heavy flooding on the Gila River in southern Arizona.

Supply and demand of the Colorado River is no longer in harmony. 70% of the river’s water is used for irrigating more than 3.5 million acres for agricultural uses. After a 12 year drought, the river has fallen to an alarming low and in the future supply will not keep up with demand!

Depletion of Groundwater in the Colorado Basin

In a recent publication,” Groundwater Depletion During Drought Threatens Future Water Security of the Colorado River Basin,” drafted by several departments at the University of California, it was discovered that, during the 108-month study period, the entire Colorado River Basin lost a total of 64.8 km3 (15.5 miles cubed) of freshwater–over a nine year period. This measurement used data taken from a NASA satellite, which accurately measures monthly changes in terrestrial, or total land water storage, from snow, surface water, soil moisture and groundwater around our planet.

While active surface water management has prevented further declines in reservoir levels, the groundwater in the Colorado Basin has been significantly depleted. The publication states, “The rapid rate of depletion of groundwater storage far exceeds the rate of depletion of Lake Powell and Lake Mead. Results indicate that groundwater may comprise a far greater fraction of Basin water use than previously recognized, in particular during drought, and that its disappearance may threaten the long-term ability to meet future allocations to the Southwest states.”

Brad Udall, of the University of Colorado Western Water Assessment, states that climate change alone will likely decrease the river’s flow by 5 to 20% in the next 35 years. With overuse of the Colorado river added to the impacts of climate change, maintaining the level of allocated water in the Southwestern states will be impossible. The “Law of the River”, written in the 1920’s, needs to be revised, because the Colorado River can no longer support the allocation of its water to so many, for so much!

*Originally published June 10, 2014

The Colorado River Basin