Can the Colorado River Sustain More Population Growth?

Insights + Opinion
Homes in Boulder City, Nevada near Lake Mead on the Colorado River.

News reports about the Colorado River over the last few months have been intense and depressing. The first ever “cuts” in water deliveries out of the river to Arizona and Nevada took hold last week, with more cuts likely coming to more states.


The ongoing 20-year drought, with the likelihood that climate change is the cause, have diminished the flow of water in the Colorado River by over 20% with even less water predicted in the future.

At the very same time, human population growth in the Southwest U.S. that relies on the Colorado River is booming. California, Arizona, Nevada, Utah, Colorado, and New Mexico have all grown fast, and even Wyoming is inching forward with new people. As just three examples, Colorado gained about 725,000 people between 2010 and 2020, Arizona gained about 760,000, and California gained 2.3 million.

People come from everywhere to move to the Southwest U.S. In Arizona alone, a recent comprehensive study about growth and sprawl showed that 56% of population growth in Arizona over the last decade was due to people moving into Arizona from other parts of the U.S., whereas 44% of the growth was due to people from outside of the U.S. migrating into Arizona.

And all of these people need water, much of which comes from an already tapped-out Colorado River.

In fact, for the last few decades, the Colorado River has been drained dry – all 4.5 trillion gallons per year are drained and diverted out of the river before it reaches the Sea of Cortez. Ninety percent of that water goes to the Southwest U.S. states, and the final 10% goes to northern Mexico just across the U.S. border. Right now, you can watch the reservoirs of the Colorado River shrink over the last few years on the website “Lakepedia.”

You don’t have to be a rocket scientist to ask, “If the river is already drained dry, from where will growing cities get more water for more people?” The convoluted answer is threefold.

First, almost all cities and states in the Southwest U.S. have been spending a lot more money on water conservation, water reuse, and water recycling. As just two examples, both the metropolitan areas of Los Angeles and Las Vegas have invested hundreds of millions of dollars in water conservation mostly by paying homeowners to install drought-tolerant landscaping (xeriscaping) in their yards. Thus, by spreading the water thinner and reusing/recycling it, you can spread what water is available to even more people.

Second, many cities in the Southwest U.S. continue to propose new water projects that try to 1) get more water out of the Colorado River, or 2) transport water into their city and state from far-away places, or 3) desalinate ocean water. All of these proposals are very expensive and complicated. For example, Pima County, AZ, (Tucson) is proposing a $4.1 billion desalination plant at the Sea of Cortez in Mexico, and then proposes to pipe the water north to Tucson. As another example, Washington County, Utah, is proposing a multi-billion dollar pipeline out of the Colorado River at Lake Powell. This list of these plans and proposals goes on and on. Thus, with all of these proposals, more water can theoretically be supplied to a growing human population but the cost of water for ratepayers in cities gets a lot more expensive.

Finally, about 70% of all of the water that is currently drained out of the Colorado River is sent to farms in the region. Every state in the Southwest U.S., and even in northern Mexico, have vast acreages of farms that receive Colorado River water. Millions of acres of crops are grown – some of that is vegetables for people to eat, much of that is hay for cows to eat, and even rice and cotton – all with water from the Colorado River. That water can, and often is, sold by the farmers to cities because the cities can pay a high price for the water making it a lucrative business for farmers to stop farming. Thus, by farmers selling water to cities, the human population can grow as the number and acreage of farms decreases.

So yes, even though there is less and less water in the Colorado River, more and more people can theoretically be supported in the Southwest U.S. with what water is available. The tradeoff is that urban landscapes get dryer and more xeriscaped, water gets more expensive in cities, and a lot fewer farms will be growing food in the region.

All of these issues and tradeoffs bring up a lot of questions, for example:

  • Does it make any sense to be promoting population growth – from both inside the U.S., and internationally – into our already parched Southwest U.S. desert?
  • Should the U.S. even be growing crops in the desert which already causes the complete destruction of the Colorado River?
  • Will the Southwest ever reach a point where no more water can be bought, piped, or pumped, and growth will actually be stopped due to a lack of water?

Population growth is often thought of as a “third rail” in American politics – an issue so controversial that no one wants to talk about it or try to solve it. It didn’t used to be that way. In fact, in the 1990s, President Clinton appointed the “President’s Council on Sustainable Development” that included a “Population and Consumption Task Force” that recommended “stabilizing the U.S. population.” Even here in Colorado where I live there’s a history of confronting population growth. Former Governor Dick Lamm made controlling growth the centerpiece of his races, and victories, for governor in the 1970s and 80s.

Right now in Colorado, we are experiencing all three of the tradeoffs of population growth and water in the Denver area:

1. Most cities have enacted water conservation programs that spread water even thinner, allowing more growth.

2. Many cities are raising water rates to pay for new expensive water projects.

3. The agricultural landscape is being devoured by growth and disappearing as thousands of acres of subdivisions replace farms around the metastasizing Denver megalopolis along the mountains.

If we do nothing in the Colorado River basin, we will get more people, fewer farms, higher prices for water, as well as fewer green and lush landscapes. Further, and solely from my river-conservation perspective, with more people and the need to stretch that water even thinner, the Colorado River – and all the rivers in Colorado – will likely continue to have every single drop of water drained out of them with little hope for a river’s ecological health or potential restoration.

Is that the really Southwest U.S. – and the America – we want to live in?

Gary Wockner is a river-protection activist in the Southwest U.S. Contact: GaryWockner.com

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