Entsminger and D’Antonio on how dry a future Colorado River the upcoming negotiations should consider

Daniel Rothberg yesterday published a very helpful Q and A with John Entsminger of the Southern Nevada Water Authority that gets to the heart of one of the really important discussions now underway in the Colorado River Basin:

Rothberg: You mentioned not that long ago, testifying in Congress, that “the river community is far from a consensus about how dry of a future to plan for.” What are some of the differing opinions right now? And where are people on establishing that baseline of what the future looks like for the river?

Entsminger: I was on a panel at the University of Colorado Law School within the last six weeks or so. And a couple people on the panel were asked that question of how dry a future should we be planning for, and I said I thought an 11 million acre-feet annual flow of the river is probably a good place to start based upon what I’ve heard from folks like Jonathan Overpeck and Brad Udall and other smart climate scientists.

But there were some folks on that panel that threw out a number of 13 to 14 million acre-feet, which, frankly, is quite a bit more water than the average of the last 20 years. So I think just from that exchange, you can see that there isn’t currently a consensus on what sort of worst-case scenario should we be planning for, as we negotiate operating guidelines for post-2026.

By way of context, we’ve had a ~12.5 million acre foot river for the past two decades, with climate change researchers (cue Brad Udall) suggesting we should expect lower flows in the future.

Entsminger didn’t name names in the Rothberg interview, but for completeness sake it is worth sharing in full the comment to which he is referring, given how it has echoed around the Colorado River Basin governance community in the last two months. I avoided writing about it at the time because, as the panel’s moderator, I wasn’t taking careful notes. But the video’s posted and I’ve had time to go back and give it a careful listen.

It came from New Mexico State Engineer John D’Antonio (the key bits from John D’s comments start here at around 16:40), in implicit response to the argument Entsminger and others have been making about the need to consider low-flow scenarios. Such low flow scenarios, D’Antonio said, would leave Upper Basin plans for new water uses above and beyond what they’re currently taking from the river “high and dry”:

13.5 million acre feet, 14 million acre feet is a little bit more realistic. I get it, it’s not there now. But it could be there.

At the Boulder conference, Entsminger made the argument (an argument with which I agree) that a range of planning scenarios is appropriate. In fact, he argued, 11 maf may not be dry enough, but it may be the biggest drop that we can realistically hope to get the political support needed to develop a plan for. To the extent that D’Antonio’s comments are representative of any broader Upper Basin sentiment, even 11 maf may be a heavy lift.


  1. Water managers have their heads in the mud. I could have said in the water but there’s not enough of that. You can’t look at the climate change caused physical changes going on around the planet to know that we are just scratching the surface on the Colorado River problem. Paid experts are not wanting to “go low” because they want to keep their jobs. Not face a “heavy lift”.
    The prudent thing is go very low and if their is more water then fine.
    No additional use of the River can be allowed. Funds should be secured to pay ag to improve their irrigation efficiencies. Maybe crop changes are needed.

  2. In response to Patrick . . . You can have new users, just not additional users. Any new one would have to buy out on old one (permanently).

  3. I have seen this situation before and its result and all of the pontificators fell on their faces. In the early 1970s, I believe, a company called ETSI was created in Wyoming to slurry coal from Wyoming to power plants in the Gulf Coast Region. Legislators came unglued as they predicted dire consequences and shortages of Wyoming water. Well the water was to come from groundwater from the Madison Limestone. This limestone unit is an aerially extensive confined aquifer. A back of the envelope calculation showed that the total water to be used over the life of the projects was less than the error in calculating the volume of water in the aquifer. Furthermore, the legislature began playing with their vision of the highest and best use of the water.which of course could not be predicted with any certainty. Because of the public outcry and a risky legislator the project was dropped. Lost opportunity. Remember that the water from the Madison Limestone was not coming from de-watering of the Madison but rather from the expansion of a compressible fluid, the groundwater, when the confining pressure was released by wells. A similar project took place from the Black Mesa of Northeast Arizona where coal was slurried with water from the Coconino Sandstone. After many years in operation, the project was terminated and the water use from the project is no longer in the news. This project was in place in the 1970’s at a time when computer models of aquifers were being developed. The aquifer was very carefully monitored because there are many springs of cultural and economic significance emanating from the Coconino. I believe the pipeline is still in place. The lesson is that one must be careful in projecting consequences. They run the danger of being cast into law which is effectively immutable and may lead to unintended consequences.

  4. Seems to me that the 7 states should use the best available science in assessing the system. That’s the downloaded global climate modeling.. Entsminger’s 11 million af/yr isn’t based on that science. Better to analyze the downscaled runs and develop hypothetical traces from them. Bet that will result in a number of long, low volume scenarios and a few with punctuated high years and higher average flows.

    Got to plan for that full range of potential outcomes…..

  5. Pingback: Colorado River Compact at 100; Lake Powell at 3,524.42 – jfleck at inkstain

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