As Arizona wrestles with the reality that its Colorado River supply as measured in actual wet water rather than the “paper water” doled out by the Law of the River, we’re getting a lesson in the difference between an “allocation” of Colorado River water and an “entitlement”. The place to watch this play out right now is in Pinal County, the stretch of rural desert dotted with cotton fields and alfalfa between Phoenix and Tucson.

We’re hearing a lot of talk coming out of Arizona about a collaborative effort to settle conflicts and move forward in the lead-up to a public meeting scheduled for Thursday (June 28, 2018) in Tempe. Bret Jaspers characterized what’s happening now as a “reboot” of the tortured relationship between the Arizona Department of Water Resources and the Central Arizona Water Conservation District, the agency that manages deliveries of Colorado River water to central Arizona.

The meeting will be held in Tempe and live-streamed on the Internet. Commissioner of Reclamation Brenda Burman will be speaking to, in the words of the Arizona Department of Resources “discuss the risks to the system” which, as I wrote about a couple of days ago, involve crashing Lake Mead kinda soon.

Courtesy USDA Cropscape. Red is cotton, pink is alfalfa

Pinal County is not exactly prime desert farming real estate, lacking the ready access to Colorado River water that you see in the valleys of Yuma, Imperial, Palo Verde, or on the Colorado River Indian Reservation. With little surface flow and an aquifer that cannot sustain farming in the long run, the only real alternative is imported Colorado River water via the Central Arizona Project, the canal that pumps water up from the Colorado River. But that is very expensive water, tough to afford without subsidy if you’re growing alfalfa and cotton.

And so subsidize we have (see this from Michael Hanemann for a history of CAP subsidies). Everybody’s irrigation water is subsidized in the West, but the Pinal County farmers’ water is subsidized a lot. Here’s how:

For the purpose of understanding Pinal County’s role in the current discussions, the key subsidy to look at is the deal signed by the counties’ ag interests in 2004 as part of the Arizona Water Settlements Act. Faced with high water costs even under the then-existing subsidy regime, the water districts signed a deal to essentially give up stronger water rights to free up water to meet Indian water rights settlement in return for yet more subsidy. Here’s how CAP explains it:

The conventional calculation of Colorado River shortage risk, which people like me frequently report, shows a 51 percent chance of Lake Mead dropping into “shortage”, below the magic trip line of elevation 1,075 at which mandatory cutbacks kick in, in 2020. But a new approach to modeling risk, which lots of folks (*cough* me *cough*) think more accurately represents the changing climate, shows a significant risk of a much quicker drop in Lake Mead’s levels, blowing quickly past 1,075, with a greater than 50 percent chance of dropping below 1,050 sometime in 2020. Absent actions to reduce water use, Lake Powell has a greater than one in four chance of dropping near power pool (the level at which it could no longer generate electricity) by the mid-2020s.

It is to the Bureau of Reclamation’s credit that they’re not only running the new modeling methodology in parallel with the more traditional approach, but that they’re doing this in a very public way, presenting both last week at the Basin States principals meeting in Santa Fe as part of the federal effort to get negotiations over water use cutbacks back on track.

Here’s the Mead graph showing the traditional modeling approach (the blue) and the newer “stress test” (shown in red):

I like this graph (kudos to Carly Jerla and the other wizards at the Bureau for coming up with such a clear visualization) because of how intuitively it shows how different the answers are when you use the two different approaches. Especially visually striking is the probability “cloud” showing the statistical range of possibilities. The old blue approach shows a decent chance of wetness refilling reservoirs. The newer red approach not only offers no such blue bits of optimism, but shows some statistically credible chances of Lake Mead seriously tanking very soon.

The difference between the two modeling approaches gets to the heart of the importance of the “period of record” you use to analyze river flows in support of decision-making.

The traditional (blue) approach uses historic river flows from 1906 to 2015 as the basis for a statistical simulation of the range of possible futures given current reservoir levels. This is classic “stationarity” – assume the future will be like the past. The specific model then uses what’s called the “index-sequential method” (ISM), which is a bog standard way of modeling the statistics of river flows.

The new approach (red), which has come to be known as the “stress test”, is based on the view of some water managers and scientists that the old full-record approach is understating risk, because the past climate – especially in the case of the Colorado River that exceptionally wet first quarter century of the record – is putting more water in the river in your simulations than we can realistically expect any more because of a warming climate. The stress test still uses the ISM, but instead of the full record, it uses 1988-2015, which seems more like a modern climate than the full thing back to 1906.

the debut of the “stress test”

The “stress test hydrology” was pioneered by Eric Kuhn of the Colorado River District and John Carron of Hydros Consulting (disclosure I have worked with both of these people and Eric and I are writing a book about, among other things, the importance of the choices of the period of record used in the analyses that underpin today’s Law of the River). Eric and John began developing the technique in 2013 in response to then-Interior Secretary Sally Jewell’s call for the development of more robust drought contingency planning in the Colorado River Basin, and Eric first talked about it at the 2013 meeting of the Colorado River Water Users Association. (see Homer Simpson, right)

It’s important to understand that neither the full period of record, nor the stress test,  is “right” in any objectively specifiable way. The question for water managers is whether the method you’re using is giving you an honest feel for the range of futures you have to manage for. It seems pretty clear to me that the red lines are telling us something really useful about the risks of climate change in our near term decision making that the blue lines miss, and that they are a more helpful way of thinking about what we should expect than the blue lines. In including these model runs in the presentation done by Bureau staff and Reclamation Commissioner Brenda Burman at Tuesday’s Basin States principals meetings, federal officials are sending a similar signal.

The point of all this is to inform decisions about getting the stalled “Drought Contingency Plan”, which would reduce water use and protect levels in Lake Mead and Lake Powell, back on track. Here’s a red line/blue line representation of the risks of Mead hitting 1,025, a level at which deep cuts will be inevitable. The solid line is the risk without a DCP, the dotted lines are the risks with various flavors of DCP:

And lest we forget, those of us in the Upper Basin face risks, too. Here’s the blue line/red line risk of Lake Powell reaching 3,490, which is the point at which Glen Canyon Dam can no longer generate electricity – a trip line we in the Upper Basin prefer not to approach, let alone cross:

The Upper Colorado River Commission, at its meeting this afternoon (Wed. June 20, 2018) in Santa Fe, voted to end its participation in the Colorado River System Conservation Pilot Program, in which water users, mostly farmers, were compensated for conservation measures in an effort to create “system water”.

“System water” is a tricky concept, and therein lay the problem. Saved water simply stays in the system, flowing down rivers until either a user downstream takes it out themselves, or until it makes its way unmeasured and unaccounted for into Lake Powell, at the bottom of the Upper Basin. This is great! Leaving water in rivers, eventually getting it to Lake Powell, is a good thing! But not having an accounting system to track who put it there makes its use in long term management of the Upper Basin’s obligations under the Colorado River Compact problematic, removing the big incentive for people to do it in the first place. “Any water that is currently conserved,” the UCRC resolution explained, “is subject to use by downstream water users or release from existing system storage prior to being needed in response to emergency drought conditions, thereby defeating the intended purposes of Demand Management.”

(l-r) Felicity Hannay, Amy Haas, Don Ostler, and Karen Kwon at the June 20, 2018 meeting of the Upper Colorado River Commission. It was Ostler’s last meeting as UCRC executive director. Haas takes over the position July 1.

“It does not,” said the UCRC’s resolution approved this afternoon, “provide a means for the Upper Division States to account, store, and release conserved water in a way which will help assure full compliance with the Colorado River Compact in times of drought.”

This highlights a thorny but common water management dilemma – whose water is conserved water. Bruce Lankford has dubbed this problem the “paracommons” (I wrote about it here, in a blog post that was a rough draft for the explanation of this issue in my book). Here’s Lankford:

In a scarce world, society is increasingly interested in the efficiency of resource use; how to get more from less. Yet if you ‘save’ a resource, what does that mean and who gets the ‘saved’ resource? In other words who gets the gain of an efficiency gain?

The problem the Upper Basin states – Wyoming, Utah, Colorado, and New Mexico – are trying to avoid is a “call” on their Colorado River Compact obligation to deliver 75 million acre feet of water past Lee Ferry every ten years (lawyer fine print alert: maybe it’s really 82.5 million acre feet every ten years if you include water for Mexico and whatever you do don’t call it an “obligation to deliver” because Upper Basin lawyers will wag their fingers and explain that it’s really an obligation not to deplete). If Lake Powell drops too low too fast, this could be a problem, so some sort of planned, staged conservation effort ahead of time might help forestall the risk. But without some way to earmark and account for the water, the Upper Basin states have been leery of expanding the effort.

Wyoming State Engineer Pat Tyrrell, who took the lead at this afternoon’s meeting explaining the decision, drew a distinction between “system water” and “state water”. What the Upper Basin states are looking for, he explained, is some way of tagging the water saved as it builds up in Lake Powell, so that if a Compact call were ever to come, it would be clear who had contributed what to meeting the Upper Basin’s obligations.

In the Lower Colorado River Basin, new rules negotiated in 2007 created a category of conserved water called “intentionally created surplus” (ICS) – big water agencies, especially the Metropolitan Water District of Southern California, could conserve water and leave the savings in Lake Mead, earmarked with Met’s name on it in the Colorado River accounting system for future Met use. This was a big deal at the time, removing the conservation disincentive created by the problem that without such an accounting system, conserved water simply reverted to other users as “system water”.

The Upper Basin states would like something similar, and there was apparently some progress at this week’s meetings in Santa Fe on that front. Creating some sort of an ICS-like water bank in Lake Powell (or somewhere else in the Upper Basin reservoirs) would take approval of all seven states and, likely, formal authorization by Congress. There appears at this point to be general agreement on the concept among the Lower Basin states (Nevada, Arizona, California), but with a lot of details to work out. But it sounded like there was a green light coming out of the closed-door Santa Fe meetings of Basin States principals, which is an optimistic note in an otherwise somewhat tense time in Colorado River water management.

It’s important to remember the word “Pilot” in the program’s name. This effort, begun four years ago, was an experiment to understand how much it might cost, how to manage a pretty complex effort, how to account for the savings, and what the institutional structure around it would need to be to accomplish the goal of heading down this path to reduce Upper Basin water use. It’s that last point that is important. In coming to terms with the on-the-ground, practical difference between “system water” and “state water”, we’ve learned a great deal that is useful in figuring out where to go next with this stuff.

In the meantime, Upper Basin System Conservation is on the shelf.

Luke Runyon had a piece over the weekend about the latest Bureau of Reclamation 24-month study, the increasingly bleak monthly modeling run that shows Colorado River reservoir levels dipping and diving in a way that the Metropolitan Water District of Southern California’s Jeff Kightlinger described thus:

“We’re in uncharted territory for the system,” says Jeff Kightlinger, general manager of the Metropolitan Water District of Southern California, the water wholesaler for the greater Los Angeles area, which relies on the Colorado River for a portion of its supplies.

“Everything is new, and it is all bleak. None of it is positive,” Kightlinger says.

In one of those small world coincidences, I was on a bike ride yesterday afternoon, wandering downtown Santa Fe, New Mexico, and bumped into (figuratively) Kightlinger. I interrupted his cell phone conversation to say “hi”, and he told me he was on the phone with Pat Mulroy, because of course on a nice warm Santa Fe afternoon one bumps into the Colorado River brain trust, connected.

Not so coincidental, really. Kightlinger and I converged with other Colorado River folks on Santa Fe for an Upper Colorado River Commission meeting this week. A bunch of side meetings are also underway to, in the words of one of the convergents, “try to jump start” the stalled Drought Contingency Plan discussions.

Kightlinger’s right about the “uncharted territory” thing. The DCP is an effort to cobble together a map of the water management terrain ahead as we’re speeding toward – well, speeding toward something that we’re not quite sure what it is but it’s probably really bad.

My main reason for tagging along to the Santa Fe meetings is the chance for some “side meeting” time with Eric Kuhn, my collaborator on a new book that is looking closely at how we got here. In particular, we’re looking at the “charts” (to borrow Kightlinger’s metaphor) that we did make beginning with the 1922 Colorado River Compact – the rules guiding how we would develop the river’s water, and our hydrologic understanding that was used to draw them. The reason this is so “uncharted” is because we (they?) didn’t do a good job at all of contemplating the “what if” scenario of river less than their rosy planning assumptions of a booming Colorado River with surpluses for all.

In fact, the framers did make a roadmap of sorts, with the Colorado River Compact’s long forgotten article III(f):

(f) Further equitable apportionment of the beneficial uses of the waters of the Colorado River System unapportioned by paragraphs (a), (b), and (c) may be made in the manner provided in paragraph (g) at any time after October first, 1963, if and when either Basin shall have reached its total beneficial consumptive use as set out in paragraphs (a) and (b).

So bad were their maps at the time that they actually thought there was not only plenty of water for full development of the farms and cities we now see, but that they would have to reconvene in 1963 to parcel out an additional allocation of more water!

By 1963, there was not only no discussion of a surplus, but active discussion of how to cope with the fact that there wasn’t enough water for even the basic allocations laid out in the compact. And yet, here we are today, 50 years later (and a nearly century after the compact was signed), still with no chart.

In addition to my happy accident of bumping into Kightlinger, I rode past a gauge on the Santa Fe River just downstream from downtown Santa Fe, forlornly waiting for water to measure. It was an omen, a nice literary device to support my hope that the DCP jump starting yields some progress this week.

A typical John Fleck morning these days involves a cup of coffee (or two) and a curlup in the comfy chair as dawn creeps over my backyard while I wander the western United States looking at USGS stream gauges.

Today’s gauge-of-the-day is my friend and colleague Eric Kuhn’s, at Glenwood Springs, Colorado. It’s just downstream from the junction with the Roaring Fork. Flows of ~3,600 cubic feet per second on June 13 were the fourth lowest since gauging at that spot began in 1967.

Important to understand what this is telling us. This is the measure for the main stem of the Colorado as it flows out of the mountains over the divide from Denver. It is not what in overall basin management we think of as the “Colorado River” as a whole, which the water managers in the state of Colorado charmingly call the “big river”. At this point the “Colorado” is just one of three big tributaries – the Green, the Colorado, and the San Juan. To understand the overall health of the “big river” system, you need to look at all three. More on that tomorrow.

Colorado River at Glenwood Springs

The driest years, in order:

1. 2012: 2,230 cfs
2. 2002: 2,280 cfs
3. 1977: 2,870 cfs

Median flow for this point in the year is ~9,600.*

* There’s a slight discrepancy between the numbers reported on the USGS web site when you click on the link above, versus the numbers I’m getting downloading the USGS data and doing my own analysis directly. Dunno. YMMV.

** Code here.