Colorado River Water

Agriculture was the main driver of development along the Colorado River. According to a recent report from the U.S. Geological Survey, 85 percent of water withdrawals went toward irrigation between 1985 and 2010 (Maupin 2018). The fields around Yuma, Arizona, and the Imperial and Palo Verde valleys of California consume more than 4 million acre-feet of Colorado River water annually, nearly a third of the river’s annual flows. But with population growth, water use has shifted to urban needs.

In Colorado, for example, 95 percent of water imported from the Colorado River headwaters through the Colorado-Big Thompson (CBT) project was once used for agriculture; now, that number is closer to 50 percent. As another example of the complexity of systems in the Colorado River Basin, CBT water is divided into units which can be bought and sold. The amount of water in a unit varies year to year depending on the total amount of water available; when CBT is at full capacity, a unit is one acre-foot. Agricultural users owned 85 percent of the units when trading began in the late 1950s, but currently own less than one-third of available units. Municipalities own the balance, but often lease the water to farms until it’s needed. The current price for a CBT unit is close to $30,000.

Such water-sharing agreements are becoming more common in a system stretched too thin. Rotational fallowing, also known as lease-fallowing or alternative-transfer mechanisms, has played a role in shifting water from farms to cities. Farmers in the Palo Verde Valley struck a deal with the Metropolitan Water District of Southern California, which serves 19 million customers, to fallow between 7 and 35 percent of their land on a rotating basis. Metropolitan’s customers, in turn, get the water, which can be stored in Lake Mead. Similar deals, still underlined with tension but increasingly accepted, exist between Southern California municipalities and farmers in the Imperial Valley and between cities and farmers along Colorado’s Front Range urban corridor.

For their part, cities tend to tout conservation and development efforts they’ve made with water in mind. Many are encouraging density, reducing the water needed for landscaping; some have implemented turf-removal programs; and toilets, showers and other fixtures have become more efficient. Metropolitan Water District of Southern California chalked up a 36 percent per capita reduction in water use from 1985 to 2015, a time of several droughts, according to Planning magazine (Best 2018).

In Nevada, the population served by the Southern Nevada Water Authority has increased 41 percent since 2002, but the per capita consumption of Colorado River water fell 36 percent. The agency’s Colby Pellegrino, speaking at a September 2018 conference called “Risky Business on the Colorado River,” said conservation is the first, second, and third strategy for achieving reduced water consumption. “If you live in the Las Vegas Valley, where there is less than 4 inches of rainfall a year, and you have a median covered in turf, and the only person walking on that turf is the person pushing a lawn mower—that is a luxury our community cannot afford, if we want to continue to have the economy we have today,” she said.

Economy, culture, and values have been at the core of the basinwide debate about how to respond to the drought. No one sector or region can absorb the full burden of necessary reductions, and it’s clear that everyone must begin to think differently. Speaking at the “Risky Business” conference, Andy Mueller, general manager of the Colorado River Water Conservation District, put it this way: Instead of the intentional use of water, Colorado is now talking about the intentional non-use of water. As is everyone who lives and works in the Colorado River Basin.

This content is excerpted from the article “Hydraulic Empire” published December 14, 2018.

Allen Best writes about water, energy, and other topics from a base in metropolitan Denver, where 78 percent of his water comes from the Colorado River Basin.

Photograph: On a farm in Yuma, Arizona. Credit: Amy Martin, courtesy of American Rivers.

References

Arizona Daily Star. 1998. “Don’t Ignore Colorado Delta.” May 6, 1998.

Best, Allen. 2018. “Water Pressure: Smart Management Is Key to Making Sure Inland Cities Aren’t Left High and Dry in the Face of a Warming Climate.” Planning August/September: 40–45. https://www.planning.org/login/?next=/planning/2018/aug/waterpressure/.

Maupin, Molly A., Tamara Ivahnenko, and Breton Bruce. 2018. “Estimates of Water Use and Trends in the Colorado River Basin, Southwestern United States, 1985–2010.” Reston, Virginia: U.S. Geological Survey. https://pubs.er.usgs.gov/publication/sir20185049.