The Risk of Curtailment under the Colorado River Compact

New Study of Colorado River Cutback Risks by GWC Senior Fellow, Anne Castle and University of New Mexico Water Resources Program Director, John Fleck

With a credible risk that declines in the Colorado River’s flow could force water curtailments in coming decades in Colorado and the rest of the Upper Colorado River Basin, communities need to think about what kind of insurance is needed, a new report argues.

A repeat of drought conditions seen in the first decade of the 20th century could nearly empty the Upper Basin’s primary storage reservoirs. “While the risk of that happening remains low in the short-term, the threat increases substantially over time, and regardless of the time frame, the consequences could be dire,” said Anne Castle, the study’s lead author – a loss of economic activity, jobs, income, and community benefits in cities and rural communities that depend on the water. “The chances that my house will burn down are low, but the result would be disastrous. So I buy insurance,” said Castle, a senior fellow at the Getches-Wilkinson Center for Natural Resources, Energy and the Environment at the University of Colorado Law School. “The question is – What kind of insurance against the risk of Colorado River water curtailment should water users buy?”

Castle will be discussing the study at the Upper Colorado River Basin Water Forum Nov. 13 at Colorado Mesa University in Grand Junction.

The report, written with University of New Mexico Water Resources Program Director John Fleck, connects the latest hydrology and climate science with an analysis of the legal framework governing the Colorado River’s allocation.

Drawing on water supply analyses by the U.S. Bureau of Reclamation and independent experts, the study finds that the risks are significant:

• A recent Bureau of Reclamation analysis found that a repeat of the conditions of the drought of the early 2000s could, in fewer than five years, drain Lake Powell to levels at which it would be unable to generate electricity.

• Water supply simulations commissioned by a group of western Colorado water agencies found a greater than one in three chance that flows could drop so far in the next decade that the ability of the Upper Colorado River Basin states – Colorado, Utah, Wyoming, and New Mexico – to meet their legal obligations to deliver Colorado River to downstream users in Nevada, Arizona,California, and Mexico would be in grave jeopardy.

Those hydrologic realities collide with legal institutions designed nearly a century ago that allocated far more water than the river has, without clear rules for handling sustained low flows.

The result, the report found, is significant risk of shortfall combined with uncertainty about whose water supplies would be cut, and by how much.

This suggests a need to prepare now, so communities are not blindsided, the report’s authors write.

Options include:

• Negotiating legal agreements among the Colorado River Basin states to clarify rules for sharing shortages

• Setting up voluntary, temporary, compensated water conservation programs now to bank conserved water as a hedge against risk

• Waiting – not taking proactive action, but rather letting the chips fall where they may, an option the authors warn is high stakes poker

The authors caution against litigation against the Lower Basin states of Arizona, California, and Nevada as a path to settling the issues. Such litigation could drag on for many years, creating uncertainty and hindering the types of collaborative agreements that have kept the River sustainable so far, they argue.

Full paper: The Risk of Curtailment under the Colorado River Compact

Risk of Curtailment Summary