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Blog Post · March 4, 2024

The Colorado River’s Hydrology is Changing. Can We Adapt?

photo - Lake Mead Near the Hoover Dam

The Colorado River is changing. Nobody knows that better than JB Hamby, chairman of the Colorado River Board of California, and Bill Hasencamp, manager of Colorado River Resources for the Metropolitan Water District of Southern California. We sat down with them to find out how the Colorado River’s doing—and what’s next for the states that rely on its dwindling supplies.

Despite a wet winter in 2023, the Colorado River basin is still in trouble. Why?

Bill Hasencamp: Since the year 2020, the entire western US has experienced a similar hydrology: three hot, dry years followed by one wet, cold year. In California, those dry years have seriously depleted storage. On the Colorado River, Lake Powell and Lake Mead dropped significantly, though there was enough storage to avoid massive cuts. In a short-term drought, the Colorado is extremely resilient because it has so much storage. But we know that long-term there’s a supply-demand imbalance, and that’s our focus.

JB Hamby: In the summer of 2022, the Bureau of Reclamation told the basin states that despite prior plans to protect against drought, we could reach “dead pool” at Lake Powell and/or Lake Mead in just a few years. That meant that water levels in depleted reservoirs would get so low that water physically could not pass through the dams. This would significantly disrupt the lives of tens of millions of people who rely on the Colorado River in the lower basin states (Arizona, California, and Nevada), on Tribal lands, and in Mexico.

The last 20 years have demonstrated that hydrology is on a drier trajectory, and we have to adapt in real time to these new climate realities. As supply has dwindled, demands have decreased—but not enough. Moving forward, we have to resolve the supply-demand imbalance and prepare for a future in which climate change means even more variability and declining flows.

What makes the Lower Basin Plan such a big deal?

JBH: In 2007, all seven basin states—including Colorado, New Mexico, Utah, and Wyoming—developed the Interim Shortage Guidelines to apportion reductions, if needed, based on best available science and information at the time. They turned out to be insufficient against worsening and persistent drought. In 2019, the basin states adopted the drought contingency plans, and they, too, turned out to be not enough.

In 2022, Reclamation asked the basin states to come up with a plan to cut 2–4 million acre-feet in 60 days. On the top end, that’s over half of what Arizona, California, and Nevada’s cities, Tribes, and farms use in any given year. For context, when California permanently reduced its water use by 800,000 acre-feet back in 2003, that effort took over five years to negotiate and ten years to validate in the courts.

It was an extremely tense time: we faced pretty bleak scenarios if massive and unprecedented water use reductions didn’t materialize. Despite this, Arizona, California, and Nevada regrouped, rolled up our sleeves, and forged a plan to protect the system within months.

In May 2023, we submitted the Lower Basin Plan to Reclamation. The plan will conserve three million acre-feet of water by 2026 and leave that water in the Colorado River system. It’s the largest water conservation effort ever established between Colorado River basin states and a collaborative effort to protect the system.

These reductions must be hitting Southern California hard. How is the region coping?

BH: Twenty years ago, Metropolitan’s demands for imported water, which comes from both the Colorado River and Northern California, were over 2 million acre-feet each year; last year we were down to 1.2 million acre-feet. Our demands are so low that we’re able to store a record amount of water in Lake Mead and reduce our diversions. And we had a good supply from Northern California last year. All these combined to help.

On the Colorado, large reservoirs can help mitigate impacts of one or two really dry years. Even when storage is low, there’s still 20 million acre-feet available, which gives you the flexibility to adapt over time to changes.

JBH: What’s unique and special about California is its creative partnerships, which have enabled water conservation. These don’t really exist in nearly the same way in our sister states across the basin. Metropolitan, Palo Verde Irrigation District, Coachella Valley Water District, Imperial Irrigation District, Bard Water District, and the Fort Yuma Quechan Indian Tribe are all critically tied together through durable and adaptable agreements that effectively calibrate California’s use to the available supply.

These partnerships began 21 years ago. They weren’t initially easy or welcomed by all, but they’ve demonstrated a durable capacity to do big things consistently over the years, and they’ve provided a framework to do even more. And it provides a model for other states to follow moving forward.

Which initiatives are you most excited about? Where will the challenges lie?

JBH: The 2007 guidelines that manage the river expire in 2025, so we’ve been working on what comes next. How are we going to operate the Colorado River in a sustainable way for next 20–30 years, or beyond? Within the upper and lower basins, how do we learn to live with less? All seven basin states and Mexico need to have critical conversations about how to respond to new trends and resolve historic, long-held differences.

BH: I’ve been working on the Colorado River for 22 years and I’ve heard people offer doom and gloom about the river. And during those 22 years, I’ve seen the opposite. Time and time again, we’ve figured out how to use less water and thrive. Climate change likely will make things drier and tougher, but working together we can figure it out. The naysayers are out there, but at the end of the day, it’s a success story.


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