Researchers investigating the historic stresses of the American West’s water supply have identified a simple solution that could put parts of the Colorado River Basin on a more sustainable path.

In a new paper published last week a consortium of scientists and water experts including Julianne Quinn, an assistant professor in the University of Virginia Department of Civil and Environmental Engineering, and UVA Darden School of Business professor Peter Debaere conclude that closing Colorado’s “free river conditions” loophole should be a key first step to reducing water stress in the region.

In Colorado, when the river carries enough water to meet everyone’s needs, the “free river condition” allows anyone — regardless of whether they own water rights — to take as much as they want from the river. The provision is a relic of water-sharing agreements among the seven states, 25 Native American tribes and parts of Mexico — some 40 million people — for whom the Colorado is a lifeline.

“Closing this loophole in Colorado’s water rights system could save millions of cubic meters of water and be the state’s modest contribution to solving water stress in the Colorado River Basin,” said Debaere, an expert in water economics and markets.

A Region Thirsting for Solutions

Quinn leads the National Science Foundation project, which received seed funding from UVA’s Environmental Institute, under which the analysis was conducted. She specializes in optimizing water resources management through mathematical modeling to help water managers balance competing objectives. 

“Our project goal is to integrate supply-side water management through reservoir operations with demand-side management through fallowing programs in which farmers are paid for not irrigating their land,” Quinn said.

The Costs of ‘Free River Conditions’

While trying to determine appropriate payments for a fallowing program, the team discovered the free river loophole, Quinn explained.

“It threatens the success of any payment program,” she said. “If the water ‘saved’ by paying farmers not to irrigate results in more frequent free river conditions, someone else can then legally divert that saved water in excess of their right, defeating the purpose.”

For example, during free river conditions in 2017 — despite a decade and a half of drought — Quinn’s team’s analysis estimated 108 million cubic meters of water were diverted that could have been reserved in Lake Powell. 

Moreover, Lower Basin states have the right to issue a “compact call” should the Upper Basin states exceed their sharing obligations under the century-old Colorado River Compact. That could trigger sudden usage cuts, putting these states, including Colorado, in a bind they could have avoided.

With some existing sharing agreements expiring at the end of 2025, the seven states are again negotiating their rights to the Colorado River.

Debaere, who, like Quinn, is a UVA Environmental Institute-affiliated faculty member, said closing the loophole is a small step, but one that opens doors to future reforms.

“This is not a technological solution,” Quinn added, “but a pragmatic end to a legal loophole in the management of water in the system.”

Publication

The paper's co-authors include T. Li (International Business School Suzhou, Xi'an Jiaotong-Liverpool University, Suzhou, China); S. Fox and K. Bennett (B3 Insight, Denver); P. Block and K. Hietpas (Department of Civil and Environmental Engineering, University of Wisconsin-Madison); M. Mekonnen and S. Sharma (Department of Civil, Construction and Environmental Engineering, University of Alabama, Tuscaloosa, AL); B. Richter (Sustainable Waters, Crozet, VA; and S. Singh (Department of Systems and Information Engineering, UVA).

This article is published on UVA's School of Engineering and Applied Sciences and has been edited from the original version published by the UVA Darden School of Business.