What might planning for an 11 million acre foot or 10 million acre foot Colorado River look like?

One of the central questions dimly visible in the early discussions around the upcoming renegotiation of the Colorado River’s water operations and allocations rules is the question of how bad a “worst case” scenario should be considered.

This is crucial, because it constrains what sort of questions must then be confronted. The lower the future flows considered, the more likely it is that the negotiators will have to stare down the third rail question of how much water the Upper Basin can delivery hydrologically, and must deliver legally, at Lee Ferry, the dividing point between the Upper and Lower Basins.

For the century since the Colorado River Compact was signed, we’ve avoided dealing with that central question – what happens if the river’s flows are so low that the Upper Basin cannot deliver the 7.5 million acre feet per year (or 8.25 million acre feet, we can’t even agree about which number to argue about) contemplated by the compact’s Article III.

This question is so untouchable that in work done for the 2012 Basin Study, the Bureau of Reclamation’s modelers famously added what came to be called “miracle water” at Lee Ferry every time one of their model runs dropped below the threshold that might have otherwise triggered this legal argument.

Under the low flows possible under climate change, we face a stark choice – either we reduce the Upper Basin’s Lee Ferry deliveries below 7.5/8.25 maf, or we will have to curtail existing Upper Basin uses. Advocates of modeling such low flows in the planning scenarios are essentially saying – Let’s have that conversation now.

At the tale end of yesterday’s (Friday 10/15/2021) House Natural Resources Sucommittee on Water, Oceans, and Wildlife, it was California Rep. Jim Costa, a congressman from outside the Colorado River Basin, who asked the question pointed at the heart of the matter – how do we redo water allocations that make no sense in a river much smaller than contemplated in our hallowed Law of the River?

He was addressing a panel of representatives from each of the Colorado River Basin states (his comments start around 2:30 here):

The Law of the River and the quantification of the Upper and Lower Basin states amounted to some 17 million acre feet of water that was determined at that time was the annual flow of the Colorado River, and we know that in the last two decades its been more like 12.4 million acre feet, and that doesn’t account for other Native American tribes that have reserved water right claims that have yet to be resolved. So there’s just a tremendous amount of demand. And with climate change, we know the yield is only going to decline.

This is the question I’d like to submit to all of you, and if you want to provide written statement to your answer I think we would appreciate that.

Let’s say the annual yield over the next 30 years is 10 million acre feet. I don’t know, with climate change, maybe it’s plus or minus. How do we take into account how we got to the original allocation, with the Upper and Lower Basin States and the Native tribes, the sovereign nations, and then reallocate that on a lot less water.

At this point all we can see through the public windows into discussions about next-step Colorado River management guidelines is shadow boxing on this question.

But testimony yesterday from Southern Nevada’s John Entsminger suggests the public shadowboxing we’re seeing on this question is representative of disagreements in the private discussions. (I quote here from John’s written testimony.)

Despite the fervent warnings from internationally renowned scientists like Jonathan Overpeck and Brad Udall that urge us to plan for a future with even less than 12.3 million acre-feet, the river community is far from consensus about how dry of a future to plan for. And, while this panel was asked to talk about drought, on-the-ground evidence suggests the Colorado River basin is not experiencing drought but aridification – a permanent transition to a drier future. If we are to build upon the river’s many successes over the last 25 years, we must confront the magnitude of the challenge in front of us and quickly reach agreement on what future scenario we’re willing to plan for. (emphasis added)

Speaking two weeks ago at this year’s Getches-Wilkinson Center conference in Boulder, Entsminger put a number to Southern Nevada’s thinking. In the next iteration of its long range water resources plan, Entsminger’s Southern Nevada Water Authority will include a “what if” planning scenario for how the agency would deal with an 11 million acre foot per year Colorado River. This is not to say that Southern Nevada expects an 11 million acre foot river, but rather than it believes it needs to have a plan in place should that happen.

I could be wrong, but so far I’ve seen no public evidence that any of the states of the Upper Basin are willing to entertain flows that low in the planning scenarios to be considered in the modeling done to support the upcoming negotiations. I look forward to seeing the written answers the basin states’ representatives submit to Costa’s question.



  1. As a member of the Southern Nevada professional community, and the greater river community, I’m glad to see John Entsminger considering worst case scenarios, what any prudent water manager should consider given the hydrologic conditions we are facing.

    On another note…..imaginary water? Only the Bureau would do this, and many other weird-ass things

  2. A Call on the Upper Basin presents quandries yet to considered. Do their allocations take precedence over the delivery requirement? What if 7.5 or 8.5 maf does not exist? Will there be a proportional figure for Upper Basin consumption .and downstream delivery? Does the Upper Basin cut back to make full delivery at Lee’s Ferry? Can a Call curtail all Upper Basin diversions junior to the ’22 Compact? i.e. Most all of CO’s TMDs are junior to the Compact, now primarily serving M/I uses. Will CO municipalities be cut off in order of seniority of the TMD? The Upper Basin needs to start going through the processes facing the Lower Basin.

  3. RE Douglas Blatchford: Your forgot the Fed’s catch all “Surplus Water,” that, has led us all astray. Too many loopholes lacking definition and true guidance. I’d venture that there never was such a thing. 🙂 Greg

  4. “Shadowboxing” indeed. Rep. Jim Costa put out what he called the $64,000 question. Calculate the maximum amount of conservation and any other “tools”, what is left, and how do we reallocate to that amount. One expert said “collaborate”. But there is a problem with rights. Costa said of course their are. The committee chairman jokingly mentioned the “Hunger Games” as an unwanted future.
    I think the Feds have to take this on.
    Some of the managers kept talking about all the population growth up till now and to continue. Saying that more water should be made available for growth. Really?
    I heard someone speaking of a migration of US population to water. That sounds realistic. “We” (the country) should begin making the arrangements. The southwest is rapidly becoming uninhabitable. Much of the farming will cease. Crops can’t be grown in the heat.
    Oakley, Utah lost their water source to drought so they stopped building.
    China has been building brand new cities from scratch in uninhabited areas. Could be our future. Also for the Gulf and Atlantic coast.

  5. RE: Greg Heiden: I was in the room when the term “Intentionally Created Surplus” was created, as opposed to “banking” water, and yes too many loopholes and assumptions, buried in models. In 2005 the CRSS-EZ model required surcharging Lake Mead to make it work….

  6. Just a historical note: Kevin Wheeler and I came up with the notion of Miracle Water when doing the big-river analysis for the Colorado River Water Availability Study for the Colorado Water Conservation Board. Kevin coined the term. It was a simple way, modeling-wise, to quantify the effect of a compact call in CRSS. In the end, we didn’t use CRSS.

  7. re: “I heard someone speaking of a migration of US population to water. That sounds realistic. “We” (the country) should begin making the arrangements. The southwest is rapidly becoming uninhabitable. Much of the farming will cease. Crops can’t be grown in the heat.
    Oakley, Utah lost their water source to drought so they stopped building.
    China has been building brand new cities from scratch in uninhabited areas. Could be our future. Also for the Gulf and Atlantic coast.”

    I don’t know what the ratio is for Colorado R. dependent populations but if it matches the California ratio of 20% urban/80% ag. isn’t the obvious move to just cut agriculture? There’s a lot of water to be had by doing that. Maybe this doesn’t pertain to other states, I don’t know. In CA ag is only 2-4% of the economy and about the same for employment. Transitioning the ag workforce out of that sector would be much cheaper than off the wall solutions like shipping water from the Mississippi, or moving populations elsewhere.

  8. Water managers should be prepared to manage there systems with less water than has been seen historically. This is true for any system anywhere, even without climate change. It should be especially true for Colorado River basin water managers.

    Regarding migration due to water changes in the west, how much less water would it take to make you move somewhere else? For some farmers, this seems likely, especially in already overdrafted basins. But, as noted in the comments, the west has few farmers.

  9. Will – You give me an excuse to reprise one of my favorite bits that Eric Kuhn and I wrote in Science Be Dammed, where we had many occasions to wrestle with the confusions caused by “Lee” vs. “Lees/Lee’s”:
    Lee Ferry, Lees Ferry, and Lee’s Ferry are often used interchangeably but
    describe two different places. The Colorado River Compact defines Lee Ferry
    as “a point in the main stream of the Colorado River one mile below the
    mouth of the Paria River.” Under the compact, Lee Ferry is the dividing
    point between the Upper and Lower Basins and the point on the river where
    there are prescribed flow requirements. Lees (or Lee’s) Ferry is the name of
    the historic settlement located at the mouth of the Paria River where John D.
    Lee once operated a ferry. While commonly called Lee’s Ferry, the official
    government name for the historic site has no apostrophe. For this book, the
    authors have chosen to use Lee Ferry when referring to compact related
    subjects and flows.
    In this blog post, I’m referring to the Compact delivery point (“Lee Ferry”) and not the place where the ferry was located(which I prefer to call “Lee’s Ferry”, government naming conventions be damned).

  10. John–thanks for clearing that up! In that case, I’ll have to blame the bureaucrats who drew up the Compact!

  11. “I don’t know what the ratio is for Colorado R. dependent populations but if it matches the California ratio of 20% urban/80% ag. isn’t the obvious move to just cut agriculture?”

    Where will food come from?

  12. From the same places: the Central Valley, the Imperial Valley, etc. I didn’t say get rid of agriculture here. I said cut it, including the 80% of almonds/pistachios exported, the alfalfa going to Saudi Arabia, etc, etc. The shibboleth about “feeding the world” is a propaganda trick to line the pockets of large buyers of agricultural land, making it a good investment for pension funds, hedge funds and other private funds, and billionaires. This is a semi-desert. Let’s treat it as such.

  13. Agreed. We can still have ag, but it cannot be for export and profit. It must be for use- locally and even regionally. I also think we need to stop this insane idea of ‘sustainable growth’. We cannot continue to keep adding people to the region while asking to cut back on the ability to feed them.

  14. Agree.
    “Sustainable growth” is an oxymoron. The world is overgrown with people several times over. People say “well no, our cities are doing just fine, see us all driving around. All good.” Well no, we actually have what may be a fatal case of climate change. Adding to any of this only makes it all worse.
    We not only need to stop growth we need to reverse it. It is called “degrowth”. Increasing the GDP is not a good sign. It is bad; like hardening of the arteries is bad.

  15. I think they should revisit the issue and divide the water evenly among all interested parties: regardless of their historic involvement in the agreement, their development patterns, their population size etc. An even distribution to all states and tribes is EQUITABLE.

    Then it is up to those jurisdictions to manage, plan, conserve, preserve, develop responsibly and *charge their constituents appropriately for water use*. If you make people pay to play, they will automatically stop excessive and unnecessary water usage. If you make it expensive you won’t see ridiculous business ventures like ag field near the Pearce Ferry takeout *face palm*.

    It sure is going to hurt the pockets of those folks living in these areas and who depend on the Colorado for drinking water or electricity – or it could eventually lead to more sustainable development patterns and folks could end up moving away from the parched communities to locations where water is more readily available and affordable and where full-time residency makes more sense.

  16. I believe that historic times need historic measures. I thought 10 years ago they should cut all water users back 10% across the board. Cities should not have green lawns, farmers start using more water saving techniques. But we need to realize that most of our vegetables come from that area in the winter months. WE will need to learn to do without. Food shortages are in our future. WE can import more, but other countries do not have the pesticides regulations that we do. As long as the public is aware of this, and are happy with this then we can get by. How about importing water from the Columbia river. A lot closer than the Mississippi river. Columbia flows 200 million acre feet per year. Certainly 1% of that river would not affect the Northwest that much?? And 2 million acre feet into the Colorado system would help a lot. Like I started with, historic times need historic measures!!

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