How Rewilding Could Restore The Colorado River Flows


Colorado River inner gorge from Tuweep (Tonoweap) overlook, Grand Canyon NP, AZ. Photo George Wuerthner 

Seven states utilize the Colorado River water for irrigation and domestic water supplies. It is the sixth longest river in the continental United States, and its watershed covers 8% of the lower 48 states.

The Colorado Rockies lie at the headwaters of the Colorado River and snowfall at high elevations feeds the river. Photo George Wuerthner

But climate change is shrinking the winter snowfall in headwaters and is predicted to reduce the river’s flows by 10-30 percent by 2050.

Downstream storage in reservoirs like Lake Mead is already at 28% capacity. There are discussions to cut water use throughout the river’s drainage. The lower Colorado River provides water to San Diego, Los Angeles, Phoenix, Tucson, and Las Vegas, among other communities. Plus, 50% of the headwaters flows are diverted to Colorado’s Front Range, including Denver, by intra-basin transfer.

Lake Mead provides water storage for numerous communities and currently is at 28% capacity due to extended drought. Photo George Wuerthner

At present, the seven states that are part of the 1922 Colorado compact are discussing conservation measures and cuts in water deliveries.

Irrigated Ag consumes 70% of the Colorado River Basin water, and most of that water is used to grow livestock forage like hay. Photo George Wuerthner

One of the easiest ways to conserve water is to reduce irrigated agriculture which presently consumes 70% of the river water. In particular, most irrigated fields are producing hay and alfalfa for livestock feed in places like California’s Imperial Valley.

North Fork Colorado River, Kawaneeche Valley and Never Summer Range, Rocky Mountain NF CO. Photo George Wuerthner 

While conserving water through policy changes, one of the most effective and least expensive ways to retain more water is to rewild the Southern Rockies of Colorado and northern New Mexico and the Mogollon Plateau of Arizona and New Mexico. Rewilding means we reestablish and enhance native species populations and native ecosystems, so their ecological function is improved and restored.

A paper published in Bio Science by 20 authors, including myself, proposes the creation of a Rewilding System across the West that would result in massive amounts of water retention in the headwaters of the Colorado River, and its tributaries would slowly “leak” flows throughout the year. The ecological restoration of streams has numerous other environmental benefits as well.

Beaver ponds slow water flow and removes sediments improving water quality. Photo George Wuerthner

Our reserve proposal would involve three major components: the restoration of viable wolf populations and the recovery of beaver—both species have been severely reduced from their historic numbers.

A third provision is the elimination of livestock grazing on the federal lands we propose for reserves.

Our rewilding proposal would also have other benefits, including more carbon storage, which would help reduce climate warming and preserve habitat for many endangered species currently in decline.

Wolves are key influences on other wildlife, and require large landscapes to maintain viable populations. Photo George Wuerthner 

We choose wolves as one of our “keystone” species. Viable wolf populations require large landscape scale habitat, so they act as an “umbrella species .”If we have a habitat of sufficient size to support wolf populations, we automatically protect the habitat for many other species.

Wolves shape ecosystems through a “cascade effect” influence the relationship of other species. For instance, the presence of wolves can force elk to utilize denser forest stands and spend less time browsing shrubs along streams. This would permit more riparian vegetation like cottonwood and willows to survive and expand along streams.

With more riparian vegetation, beaver numbers could expand and colonize more stream courses. Beaver are ecosystem engineers. Historically, hundreds of thousands of beaver dams were scattered on nearly every creek, stream, and river across the West.

Beaver dams store water allowing it to gradually soak into ground sources rather than run off in a rush with snowmelt or heavy rainstorms. Their barriers also increase water quality by acting as settlement ponds that remove sediment.

And the creation of ponds widens the area influenced by water and favors the recovery of riparian vegetation like cottonwood and willows. These species, in turn, store carbon and provide habitat for numerous wildlife species. Up to 70% of western wildlife species utilize riparian habitat during some portion of their lifecycle.

Livestock destroy riparian areas by compacting soils which reduces their ability to hold water, and trampling banks. Photo George Wuerthner 

Finally, livestock is among the major reasons riparian areas across the West are in shambles. Livestock tends to congregate along streams where they compact soils and reduce the “sponge” effect that stores water while their hooves break apart stream banks, resulting in wide, shallow streams rather than deep, narrow ones. They also consume streamside vegetation. Thus, eliminating livestock would promote the restoration of wolves and beavers.

Grazing on public lands is a privilege, not a right. Therefore, the federal government could cancel grazing permits at any time. However, to provide dependent ranchers with a soft landing, we propose enactment of the grazing permit retirement legislation based on the amount of forage annually consumed by their cattle and the permanent closure of these allotments.

Currently, it costs the federal government far more to administer the grazing program than it receives in fees. And this does not even account for the cost to society from damaged watersheds or the lost opportunities to store water and carbon.

However, the most significant benefit to society of Rewilding the mountains of the Southern Rockies and Mogollon Plateau may be the increase of water storage and enhanced flows in the Colorado River.

Of course, implementation of our Rewilding proposal across the West would have similar benefits to other major river systems where ongoing drought is straining water supplies, harming fish and wildlife, and causing economic hardships for water users.


  1. Maggie Avatar

    Since many countries in Europe have already started re-wilding – it certainly would be about time for America to wake up & do the same. I’m sure there would be much weeping & wailing from the livestock & fossil fuel industries, however, climate change anyone???

  2. Ralph Maughan Avatar
    Ralph Maughan

    This is certainly a needed essay.

    And I know the groups that will object — the groups whose goals will serve to further deplete the land and the waters even as they claim just the opposite.

  3. Mike Higgins Avatar
    Mike Higgins

    Although I’m a native eastern Oregonian, George, what you’re proposing could provide benefits far beyond the scope of the miniscule benefits of the cattle industry. Cows on public lands is a concept that has outlived – a long time ago – its practicality and when balanced against its negative impact on our environment, is a concept that simply has to be eliminated. To continue to ignore all of its destructive impacts is foolish and when viewed in hindsight ten-to-twenty years down the road, will represent one of the many “death wishes” we humans have clung to for far too long.

  4. Michael Sauber Avatar
    Michael Sauber

    To make matters worse, lots of our irrigation water grows alfalfa which is then shipped to the middle east and other countries to feed their cattle. Rewilding could also reduce the carbon impacts of shipping that mass overseas.

  5. Ida Lupine Avatar
    Ida Lupine

    The poor Colorado River! I’m surprised that it has lasted as long as it has.

    Another story about CA too:

  6. Martha S Bibb Avatar
    Martha S Bibb

    The cow bomb problem. Idaho creates 50 million pounds of manure per Day!Cattle corporations have ruined the Snake River with pollution from all the cattle feed crops and cattle waste. That’s a real shame.
    The whole state government is controlled by the cattle industry.Talk about conflict of interest and ethics issues!

    1. Ralph Maughan Avatar
      Ralph Maughan

      I don’t think it is far off to call Idaho a fascist livestock state.

  7. Ida Lupine Avatar
    Ida Lupine

    Between poisonings and ‘not disposing of cattle carcasses properly’, the WDFW has decided against a wolf removal this year:

  8. Ida Lupine Avatar
    Ida Lupine

    ^^sorry, or at least they are not having a second hunt. If the Washington ranchers are not holding up their end of the bargain by baiting wolves‘properly disposing of carcasses’, then they should be held accountable.

    1. Jeff Hoffman Avatar
      Jeff Hoffman

      As usual, cattle grazing is a major or even THE major problem here. Cattle grazing wont be reduced unless people eat a lot less beef, or even better, none at all. All of the destruction on public lands is rooted in demand from consumption, and if you want to fix problems, fix the roots of them.

    2. Jeff Hoffman Avatar
      Jeff Hoffman

      The other response to you was supposed to be a general comment, not a response to you. Sorry about that.

      As to your comments, wolves should never be killed by humans. As in, NEVER! Humans should only kill what they eat, and their meat should be limited to natural prey animals, which doesn’t include wolves.

      Additionally, cattle should be completely removed from public lands just for starters. Cattle grazing does FAR more damage than just leaving cattle carcasses laying around.

  9. Rich Avatar

    Thanks Ida for posting the article. The words used in the article regarding grazing privileges are interesting.

    “The grim scenario now playing out on the one ranch has led the family not to exercise deeded grazing rights in the Colville National Forest, which is home to both packs, despite the fact they pay an administrative fee to do so.”

    I’m wondering whether that is really the case and if so would the rights be available to someone else? Also I thought grazing rights on public lands were leased from the government not deeded.

    1. Ida Lupine Avatar
      Ida Lupine

      I’m not sure, I always thought that the right to use could be passed to heirs, but the land belonged to the Federal gov’t.?

      But it has been minimized that a rancher did not dispose properly of cattle carcasses, and that is the real cause of the problem, and completely violates the agreement made on behalf of us, really. They have no justification for any complaint, or request to ‘remove’ wolves.

      I applaud WDFW for holding to the letter of the agreement, and I hope they are going to be on the alert for any retaliation. There have been poisonings, I’m not sure where, but it does affect the state’s population of wolves.


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George Wuerthner