Four Questions: UA Experts Discuss Drought Contingency Plan
Three UA professors, each with unique areas of expertise relating to water and the Colorado River, talk about the Drought Contingency Plan and what might come next.

By Nick Prevenas, University Communications
March 20, 2019


Horseshoe Bend is a horseshoe-shaped meander of the Colorado River located near the town of Page, Arizona.
Horseshoe Bend is a horseshoe-shaped meander of the Colorado River located near the town of Page, Arizona. (Photo: Luca Galuzzi -, CC BY-SA 2.5)

With the Western U.S. in the midst of a prolonged drought, elected officials and water-resource experts have spent the last handful of years exploring ways to protect the Colorado River.

The Drought Contingency Plan, signed by Arizona Gov. Doug Ducey hours before a Jan. 31 deadline, is one step toward maintaining safe and sustainable water levels within Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming.

"This plan is a very reasonable, carefully thought-out program that should be considered an overlay to the shortage-sharing guidelines these seven states put into place in 2007," said Sharon Megdal, director of the Water Resources Research Center at the University of Arizona.

Megdal, C. W. and Modene Neely Endowed Professor in the UA College of Agriculture and Life Sciences, adds that the Drought Contingency Plan, or DCP, should be viewed as an interim solution to ensure that the Colorado River, which serves 40 million people and nearly 8,000 square miles, can continue to provide water now and into the future.

"What was business as usual is no longer sustainable," said Karl Flessa, a professor of geosciences at the UA and one of the world's foremost Colorado River researchers.

The DCP, which is now awaiting Congressional approval, asks states, as well as Mexico, to voluntarily sacrifice portions of their standard water allotments to keep Lake Mead, on the Arizona-Nevada border, and Lake Powell, upstream on the Arizona-Utah border, from crashing.

Q: How will the Drought Contingency Plan help address Arizona's water shortage issues?

Robert Glennon

Robert Glennon, Regents' Professor and Morris K. Udall Professor of Law and Public Policy: The Drought Contingency Plan is essential for Arizona because, in case of shortages, Arizona stands to lose the most water if Lake Mead drops below certain levels. The plan shares the pain among all seven Colorado River Basin states.

While hideously complicated with an array of agreements and exchanges, there are two takeaways.

First, the various agreements essentially pay various parties to forego using water to which they are entitled. Beneath all the acronyms lies a simple reality: the plan uses market forces to reallocate water.

Second, at the center of the various water exchanges, forbearance agreements and fallowing programs are the Gila River Indian Community and the Colorado River Indian Tribes. In the past, not only were the tribes not at the table, they had rights to precious little water. In the DCP, Gila River Indian Community and Colorado River Indian Tribes are playing critical roles in helping the state navigate an ominous situation.

Q: How has the issue of water use as it relates to the Colorado River evolved during your career?

Karl Flessa (Photo: Mari N. Jensen ©2017)

Flessa: Issues surrounding water use in the Colorado River Basin have evolved a lot in the past 25 years. One important change – and it's still sinking in – is recognition that the demand for Colorado River water now exceeds the supply.

Not only has the demand increased, the supply is decreasing because of climate warming. I think it's important that both water managers and water users realize the current conditions are not a "drought," but are the new normal. Sure, we will have some wet winters now and then, but long-term, there will be less water in the river as higher temperatures cause more evaporation and more water use by plants. I'm part of the Colorado River Research Group: We're calling this change "aridification" – a transition to drier conditions. We need to learn how to adapt to this change.

Q: How will the Drought Contingency Plan change the way decisions about Colorado River water are made?

Flessa: There is more collaboration and less competition among the stakeholders. The Arizona versus California "water wars" are in the past. Nobody wants costly legal battles in the future. We all share the water and the ecosystem services the river provides. Native American tribes are now participating in decision-making. Environmental and recreational interests are now being heard. And the river doesn't stop at the border: Mexico is now an important partner in the management of the Colorado River.

We're all in this together. Here are three examples of how increased collaboration brings benefits: 1. New treaty agreements allow Mexico to store water in Lake Mead, helping to prop up that lake's level and helping prevent a formal declaration of a shortage. 2. If the seven U.S. States that use Colorado River water agree to a Drought Contingency Plan, Mexico will also participate. 3. The first-ever environmental flows across the border started in 2014. These flows to support riparian restoration are a result of a cooperative arrangement among the U.S., Mexico and environmental nongovernmental organizations.

I'm really glad to see the increased focus on water conservation and on water reuse. Conserving and reusing the water we already have is less expensive and more effective than adding more dams or importing water from other river systems. Storing Colorado River water underground, as Tucson does with its Central Arizona Project water, will help us get through some dry times ahead. Desalination, whether in Arizona, in the Gulf of California or along the Pacific Coast, could also help, but that rescue, if it comes, is at least a decade away. When we have less water to use, we'll learn how to use less water.

Q: How will the Drought Contingency Plan impact Arizonans who don’t rely on Colorado River water supplies and instead rely primarily on groundwater?

Sharon Megdal

Megdal: There are many different ways people in Arizona consume water. Some rely entirely on Colorado River water or water from the Central Arizona Project, or CAP. Some water utilities, however, pump water from underground, and that's what they serve to customers.

Colorado River water supplies about 40 percent of water needs of Arizona – some of that is along the main stem of the river and some of that is through CAP water delivered into central Arizona. That water is used in many different ways, whether its direct delivery, or stored underground and recovered, like in Tucson. Other areas pump available groundwater and replenish those supplies after the fact. A few others use groundwater and very little surface water at all.

If you're not relying on CAP water in any way shape or form or don't intend to, the DCP will not have a direct effect in deliveries. However, it will have many secondary or indirect effects. Farmers in southern Arizona, for example – if many of them decide to go back to groundwater pumping, it will affect nearby groundwater users by its impact on the water table, the cost of pumping and the depth of the groundwater wells.

In a sense, Arizona has a hydrologically related system. If there is less water coming into the state, it will directly or indirectly impact nearly all water uses.

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Resources for the media

Researcher contacts:

Karl Flessa

UA College of Science


Robert Glennon

UA James E. Rogers College of Law


Sharon Megdal

UA Water Resources Research Center


Media contact:

Nick Prevenas

UA Communications