Kathryn Sorensen and Bill Hasencamp are two experts on the lower Colorado River basin. As water users face steadily declining water levels in Lake Mead, we asked Sorenson, director of research at Arizona State University’s Kyl Center for Water Policy, and Hasencamp, who manages Colorado River resources for the Metropolitan Water District, to tell us about the long-term outlook for the river and the millions of people who depend on it.

Where are we with shortages on the Colorado River? The first-ever shortage was announced in late summer of 2021, but California is not currently taking shortages. Could that change?

Bill Hasencamp: The lower basin water users have worked collectively to avoid a shortage declaration for a long time. If not for our efforts, we would have been in shortage probably seven years ago. Arizona, California, Nevada, and the federal government, working in collaboration with Mexico and Native American tribes, have done a lot to prop up the level of Lake Mead by storing conserved water in the reservoir and funding system conservation programs. The total volume of collective actions over the last ten years has propped up the level of the lake by about 65 feet, but the last two years were so dry that we could no longer delay the reservoir dropping to a level that triggered a first-ever shortage declaration.

Kathryn Sorensen: Yuma is the iceberg lettuce capital of the country, and everyone will continue to get their lettuce because western Arizona enjoys high-priority Colorado River water rights! But here in central Arizona, even if we manage to avoid the worst-case outcomes, there will be less 30-35% less Colorado River water beginning in 2022 and probably for the foreseeable future. We’ve long known that our access to Colorado River water is lower in priority, and we’ve planned accordingly. We’ve managed to store a lot of water in our aquifers, we’ve made good use of reclaimed water, and we’ve been managing our aquifers very carefully for just this eventuality. Though there will be impacts, for the most part the cities in central Arizona have developed resilient water supply portfolios and are ready.

The states seem to be rallying to make cutbacks, but that can be a painful process. Tell us about the “500-plus” plan. What does it do and how will it help?

BH: When we negotiated and signed the drought contingency plan (DCP) in 2019, California, Arizona, Nevada, the Bureau of Reclamation, and Mexico all agreed to make additional contributions to Lake Mead to slow its decline. However, we also decided that if Lake Mead was projected to get as low as 1030 feet within a two-year period—it is currently at 1065 feet but could drop 35 feet in the next two years—then the states would figure out additional actions to slow the lake’s decline. Arizona and Nevada took the lead and based on computer modeling concluded that we would need to reduce use of the lake by 500,000 acre-feet per year—on top of current DCP contributions—to ensure sufficient reliability between now and 2026.

We developed the 500-plus plan with the goal of adding an additional one million acre feet total to Lake Mead over the next two years. This plan provides the stability we need, because sometime this spring, we’re going to start negotiations over the future long-term operations of the river.

KS: I want to give a shout-out to Bill and those involved in 500-plus, because that came together in three months—so quickly—which reflects both the problem’s urgency but also the spirit of collaboration in the lower basin.

As Bill just noted, the states, tribes, and Mexico are about to embark on a multi-year negotiation process to develop new operating rules for the Colorado River. What will be some of the key issues? Can you speak about the long-term outlook for the basin?

KS: Collaboration is the way forward. The river is not going to give us as much as we’d like, and that’s a hard reality to confront. And there are still entities in the upper basin, like tribes and other groups in Utah, who have outstanding claims to the water and expect to increase their use.

In central Arizona, we have to confront the reality that we’re looking at less Colorado River water available to recharge our aquifers. That is a huge shift for us. We’ve been using it steadily to recharge our aquifers for the last 30 years. We’re going to have to find ways to get by on less.

BH: It’s going to be a very challenging four years. In 2003, Met reduced its diversions from the Colorado River, on average diverting about 75% of the amount we did prior to 2003. That was a fundamental shift in how we manage our Colorado River supplies here in California. I think 2022 is another big shift for everyone in the basin. This first-ever shortage declaration is likely to be permanent: I think we’re never going to see a full 7.5 million acre feet available to the lower basin again. The question is not if there will be shortages but how big they’re going to be. All seven states and Mexico are going to have to adapt to this new reality.

At same time, we need to find ways to provide more water for the environment. The Colorado Delta received a pulse flow in 2021—in one of the driest years on record, we found water for the environment last year, and we’re going to need to do that in the future. Squeezing more water from dwindling supplies is a challenge, but it’s going to be a part the river’s future.

KS: Water managers are really good horse traders; it’s what we excel at. I’m optimistic because what’s the alternative? We have to succeed.