Colorado River Upper Basin states accuse Central Arizona Project managers of threatening the health of the Colorado River system

Upper Colorado River Basin state leaders, in a letter Friday (April 13, 2018), said the water management approach being taken by the managers of the Central Arizona Project “threaten the water supply for nearly 40 million people in the United States and Mexico, and threaten the interstate relationships and good will that must be maintained if we are to find and implement collaborative solutions” to the Colorado River’s problems.

The letter accuses CAP of “disregard(ing) the basin’s dire situation”, providing more water for Arizona at the expense of the rest of the basin. In doing so, it highlights a rift within Arizona, where an internal political feud over this and related issues has pitted CAP against the state Department of Water Resources and many of CAP’s own customers. That rift, in turn, has stalled diplomacy over efforts to develop a broad new plan to cut back water use across the Colorado River basin.

The letter, using language that is striking in the normally staid interstate diplomacy of Colorado River interstate water management, takes issue with CAP’s practice of using more water than it might otherwise – avoiding “overconserving”, in CAP’s words – in order to ensure continue big releases from Lake Powell upstream. That has the effect of expanding water use in the Lower Colorado River Basin at the expense of draining Lake Powell, the critical reservoir for protecting Upper Colorado River Basin supplies. The managers of the Central Arizona Project are “disregard(ing) the (Colorado River) basin’s dire situation at the expense of Lake Powell and all the other basin states” by using more water than they need to, the letter said.


On Twitter last week, in response to something I wrote here, Central Arizona Project General Manager Ted Cooke defended CAP’s practice, calling it wise placement of water orders under the 2007 rules governing reservoir storage on the Colorado River. Those rules attempt to even out storage between Lake Mead – which supplies the Lower Basin states of Arizona, Nevada, and California, plus Mexico – and Lake Powell, which maintains a storage bank for the Upper Basin states of Wyoming, Colorado, New Mexico (I raise my hand to declare an Upper Basin bias here) and Utah. The rules have created an incentive for the Central Arizona Project, which manages a big fraction of Arizona’s supply of Colorado River to avoid “overconserving” – again, this is CAP’s word – at a time when everyone in the Colorado River Basin is trying to use less water. The Upper Basin states (the letter was signed by the top water officials from all four) say that “attempts to maximize demands to increase releases from Lake Powell could ultimately accelerate lower reservoir conditions in both the Upper and Lower Basins and cause shortages in Lake Mead.”

The issue of the Central Arizona Project’s approach to this issue has been simmering for more than a year. Water managers have long known the rules created this incentive for the CAP’s managers, but the agency’s increasingly brazen public discussions of it have become problematic. The public version of the debate goes back to a March 2, 2017 meeting of the board of the Central Arizona Water Conservation District, the agency that runs the CAP. Tony Davis at the Arizona Daily Star nicely documented the debate in this story, quoting CAP water policy director Suzanne Ticknor explaining to her board the risk to Arizona of “overconserving”.

That word echoed through the Colorado River water community at a time when other states were struggling with how to conserve more water, not worrying that they might be conserving too much.

It also highlighted an increasingly divisive breakdown within Arizona on this issue. Kathryn Sorensen, director of Phoenix’s water department, was quoted in Tony’s story criticizing CAP’s approach. “The ‘risk’ of overconserving is a Colorado River that is less vulnerable to shortages and more resilient over the long run, a river that is more protective of our economy and our quality of life,” she told Davis. Others in Arizona have become increasingly critical of CAWCD/CAP approach. “CAWCD does not speak for Arizona,” Carol Ward-Morris of the Arizona Municipal Water Users Associated tweeted this week in response to my blog post about the allegation that CAP is “gaming” Colorado River water management rules.

The full letter, which has spreading quickly through Colorado River management circles this weekend, is here:



  1. Excellent post, John, thought provoking. Would be interested in hearing your take on the equally messy and CAP-related upper Gila River situation. In particular, the CAP Entity formed to guide AWSA looks to over use water that really isn’t there to begin with. We have our own drama right here in NM.

  2. It’s a depressing sign of the times that no one cares about facts any more. Not when invective gets so much more press. And when there are bloggers who are ready and willing shills for whatever juicy bit will garner them more retweets.

    Fact: On average from 2015 through 2018 Arizona used 200,000 acre-feet LESS than it was entitled to use.

    Fact: Arizona is the only state that is actually operating as though the LBDCP were in effect.

  3. KS – Your first point is good. As I have often noted on this blog, and as I explained at length in my book, Arizona’s water conservation performance has been excellent.

    Your second point is incorrect.

    Under LBDCP, California at current elevations could take 4.4maf. In 2017 it took 4maf.

    Under LBDCP, Nevada at current elevations could take 292kaf. In 2017 it took 242kaf.

    Under current USBR 2018 forecasted use, both Nevada and Arizona are projected to exceed their LBDCP targets. Arizona is not.

  4. The CA “reduction” is to create ICS; CA will take that water at a later date. NV demand is significantly below its apportionment. AZ is the only state that is intentionally not meeting demand so as to leave water in Lake Mead. The system conservation water that AZ is providing does not earn ICS credits, so AZ will never take that water.

    If DCP were in effect, what would be happening in the Lower Basin is exactly what is happening today.

  5. KS – In other words, when you said “Arizona is the only state that is actually operating as though the LBDCP were in effect” you really meant *all* the Lower Basin states are operating as though the LBDCP were in effect.

    Because it’s pretty clear – because they have said this publicly – that Met left all that ICS in Lake Mead based on the presumption that LBDCP would take effect. Had they not, the risk of a shortage declaration would go up a lot. And absent action by Arizona to get its LBDCP house in order, we’ll have no LBDCP, and Met will be likely need to take all its ICS out to avoid having that water stranded, and we’ll end up with exactly the problem Arizona hopes to avoid – a 1,075 shortage declaration.

  6. So if *all* the Lower Basin states are operating as though DCP is in effect, as you conclude, then what is the Upper Basin’s beef? Because it appears that the central premise of the UB letter is that AZ, alone among the 7 states, should permanently reduce its apportionment to significantly less than 2.8 MAF so that the UB can continue to grow its demand.

    AZ has conserved more than 850,000 AF in Lake Mead from 2014-2018. In that same period, the UB has conserved perhaps 30,000 AF in Lake Powell through the SCPP, most of which was funded by Lower Basin parties. How, then, is AZ to blame for all the basin’s problems?

  7. Terrific post, John. I got a strong sense of the inter-Arizona politics when I did my Lake Mead piece sometime back, but CAP’s activities seem to have gotten increasingly brazen. I also am enlightened by your discussion with KS, which I hope continues.

  8. KS –

    I got an email this morning from a friend who farms in the Upper Basin. He said, with what I imagine would have been a bit of a wink or a grin had we been speaking in person, that he won’t be wasting any water on alfalfa this year because there’s no water to waste.

    Water users in the Upper Basin roll their eyes at talk of “shortage” in Arizona. What you freak out about – the risk that “shortage” might reduce your available supply of Colorado River water – is a routine occurrence in the Upper Basin, where water users are dependent on whether or not there’s snow in the headwaters above their farm. Your framing – “AZ has conserved, while the UB hasn’t” – is I guess technically accurate, but so remarkably tone deaf and shows that you really haven’t heard the point your friends in the Upper Basin were trying to make in that letter.

  9. I’m not worried about shortage in the least. Arizona has planned for shortage and will be just fine. I’m also well aware that UB water users are dependent on annual flow to meet their needs. But that wasn’t the topic. The topic was the UB letter complaining about Arizona’s conservation activities.

    Your latest reply suggests that Arizona should NOT be conserving water to reduce the risk of shortage. Yet the UB letter says AZ should be conserving MORE water than it is. So which is it?

  10. Whenever, and wherever, there is a set of hard line rules there will always be those who try to maximize their benefit over the group’s benefit. A good example would be tax credits. Due to out of control spending, our treasury is in dire need of revenue. Thus, the less advantage of deductions one takes on their annual taxes, the more money there will be in the treasury. However, most people want what’s best for their wallet, and not our treasury, so they pull as much as they can for themselves by maximizing every single tax credit that’s allowed under the tax rules.

    Whether you can fault people for behaving in this manner is another issue all together, and not one I won’t address here. What I’m more interested in is the much broader issue of, what I believe to be, the stupidity of the details in the current Interim Guidelines which is causing all these problems in the first place. Clearly there needs to be a corporative UB and LB agreement on how to manage Colorado river water. I would never suggest that the idea of the Interim Guidelines was bad. However, I don’t like the way many issues were addressed, and how the annual release amounts are determined, when operating under them.

    I have a friend who is exceptional at creating math models. Years ago, I asked him to work on some models for determining release amounts. One thing that became apparent very quickly was it was near impossible to create a set of hard lines, or trigger points, for annual releases when the goal was to create long term stability. Certainly, they worked well for any given single year, or maybe even two, but that was about it. In order to create long term reservoir volume stability two things were needed. First, the concept of hard lines needed to be replaced by more vague qualifiers which take into consideration more generalized common goals, and second was that the lower basin’s 8.23 maf nominal allotment should be increased (at least at first –and to the UB folks, don’t freak out yet, there will be more, so keep reading to the end of the paragraph) to around 9 maf; however, the LB’s, so called, structural deficit above 9 maf also needed to be eliminated (by the lower basin reducing their draw).

    In case anyone is curious, I asked him to stop working on the models because, the way it is with water, the chance of everyone in the UB and the LB working together for a common good is, unfortunately, essentially impossible. I won’t even mention the chance (read: never ever) of latter happening.

  11. KS: You stated above that “NV demand is significantly below its apportionment.” Technically this is inaccurate. NV demand is often above our apportionment. However, due to return flow credits, we are able to meet demands by drawing more than our apportioned amount, and returning treated waste water for credit. This allows our final net draw to be under the apportioned amount, but it’s not due to a significantly lower demand than our (rather small) apportionment.

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