An ongoing megadrought, impacts of climate change and systematic overuse have created a crisis for the Colorado River, an essential water source for 40 million inhabitants of the southwestern United States and northwestern Mexico.
The current policies and international agreements governing this river are insufficient to maintain secure water supplies, concludes a commentary published today in the journal Science from the University of Oxford, Utah State University and Colorado State University.
The Colorado River’s major reservoirs, Lakes Powell and Mead, reached record lows this year nearing 25% capacity. A continuation of the current 23-year-long drought will require difficult management decisions.
The policy changes identified require renegotiation of the rules governing this critical shared river and are fraught with complexity
Using the Colorado River Simulation System, the researchers developed a method to calculate the cuts to water consumption necessary to balance the system if the current drought continues and estimate future reservoir storage under various management options.
The research identifies that limits to water consumption from the river’s Upper Basin – in Wyoming, Colorado New Mexico, and Utah – and reductions in use from the Lower Basin – Nevada, Arizona and California – are both needed for reservoir storage levels sufficient to maintain secure water supplies if the drought persists.
“The proposed reductions in consumptive use being considered by Upper and Lower Basin states may seem like a political impossibility at present, but they will become inevitable if hydrologic conditions persist,” says Dr Kevin Wheeler, lead author on the paper and fellow of the Oxford Martin Programme on Transboundary Resource Management.
A set of interstate compacts, court decrees, federal laws, secretarial guidelines and an international treaty collectively governs the management of the Colorado River, which is often referred to as the Law of the River. The policy changes identified in this study to stabilise the river basin require renegotiation of the rules governing this critical shared river and are fraught with complexity, impeded by competing priorities between states.
Various consumptive use strategies could deliver stabilisation if they were applied swiftly
A collaboration between the Center for Colorado River Studies at Utah State University, Colorado State University, and the University of Oxford, the commentary describes the political history leading up to the current management crisis. It also presents results from innovative research offering a new perspective on how to stabilise or reverse the decline of reservoir storage. It concludes that various consumptive use strategies could deliver stabilisation if they were applied swiftly.
However, implementing, or even accelerating, the policy changes necessary to stabilise the Colorado River system requires well-grounded insight to project the impacts of those policies on the system as a whole, say the authors.
“Although the focus of our study is a scenario of continued drought, the insights and approaches found in this piece can also be adapted to plan for other future scenarios,” says Dr Wheeler.