This week’s Topsoil Moisture Short/Very Short by @usda_oce #drought

Increases in most of the West and Plains states (except, not surprisingly, TX) led to a 1% increase across the Lower 48. 49% of topsoil moisture in the Lower 48 is now short/very short.

Renewable Natural Resources Foundation Round Table: The Challenges of Allocating #ColoradoRiver Water – Hot 20-year #drought and soaring populations #COriver #aridification

Brad Udall: Here’s the latest version of my 4-Panel plot thru Water Year (Oct-Sep) of 2021 of the Colorado River big reservoirs, natural flows, precipitation, and temperature. Data (PRISM) goes back or 1906 (or 1935 for reservoirs.) This updates previous work with @GreatLakesPeck. Credit: Brad Udall via Twitter

Click the link to read the article on the Renewable Natural Resources Foundation website (Stephen Yaeger):

Senior water and climate research scientist at Colorado State University and one of the authors of the National Climate Assessment. Photo credit: Colorado State University Water Institute

Brad Udall, a Senior Water and Climate Research Scientist at Colorado State University, spoke at a virtual meeting of the RNRF Washington Round Table on Public Policy on March 9, 2021. He discussed the imbalance between water supply and demand in the Colorado River basin, how climate change is exacerbating the issue, and the ongoing renegotiation of the river’s management guidelines.

Introduction and Background

The Colorado River basin extends into seven states (Wyoming, Colorado, Utah, Arizona, New Mexico, Nevada, and California) as well as Mexico, along with the land of 29 Native American tribes. The American portion of the basin represents 8% of the area of the lower 48 states. Altogether, about 40 million people, including the populations of all major cities in the Southwestern U.S., rely on the Colorado for some portion of their water supply. The river is used heavily for municipalities as well as agriculture, with about 4.5 million acres of irrigated land in the basin.

The water supply in the river is often measured by the water levels in its two major reservoirs, Lake Mead and Lake Powell. These are the two biggest reservoirs in the U.S. In order to maintain sustainable levels in these two reservoirs over a long time period, withdrawals from the river must equal the supply being provided by the river’s flow. This was the case in 2000, when the combined contents of the reservoirs were over 90% full. Since then, their water level has dwindled to less than 50% due to a “structural deficit” – demand for the river’s water consistently outpacing supply. This is due in large part to the fact that over the past 20 years, the basin has been experiencing its worst drought on record. The flow of the river has decreased from ~14.75 million acre-feet (maf) to ~12.4 maf. Even before the drought began, water demand was high in the basin; since about 1990, it has not reliably reached the ocean.

While the current situation in the watershed is usually described as a drought, a lack of precipitation is really only half the story. Regional temperature increases, exacerbated by climate change, have also had a significant impact on the reduction of water availability. Udall noted that evaporative losses will only become more severe as climate change worsens. The Southwest is already one of the quickest-warming areas of the country, a trend that is expected to continue. The risk of multidecadal droughts will also continue to drastically increase in coming decades. The 2000-2018 period was the second-driest 19-year period in the basin since 800 AD. While this is partially attributed to natural variation, researchers have said that 50% of the decrease in soil moisture can be attributed to anthropogenic climate change. Climate change has turned what would likely be a moderate drought into an extreme, historic drying event. Aridification and heating, along with reduction in precipitation, are causing drastically drying conditions in a river basin that tens of millions of people rely on for their water.

Historical Management of the River

In 1922, to fully allocate use of the river’s water, the basin states agreed to the Colorado River Compact. This agreement still serves as the basis for the Law of the River, which is the set of rules for the river’s allocation and management. In response to the “hot drought” happening since 2000, new modifications to the Law of the River have been necessary to prevent the reservoirs from becoming depleted. The first of these, called the Colorado River Interim Guidelines, went into effect in 2007. These guidelines set out a series of complicated rules for how Lakes Powell and Mead are operated, allowing different quantities of water to be released from them when they are at certain elevations. They constrain use of water when the reservoirs are low. One innovative structure used to accomplish this is “intentionally created surplus,” which allows parties in the lower basin to store their water in a sort of “bank account” in Lake Mead.

Around 2013, it was becoming clear that persistently dry and hot conditions were rendering the 2007 Interim Guidelines insufficient. A new agreement was necessary. As a result, two new “Drought Contingency Plans” (DCPs) for the Upper and Lower Basins were adopted in 2019. Early in 2021, for the first time, drought conditions in the river reached the point where the DCPs’ provisions were activated. Udall noted that these agreements made some progress toward making the river’s use more sustainable but were not a permanent solution.

Future Management of the River

Udall finished his presentation by discussing future prospects for sustainably managing the river in these drying conditions. In 2026, the 2007 Interim Guidelines and DCPs expire. The seven basin states, 29 tribes, Mexico, and the federal government have already begun the multi-year process of renegotiating a new set of guidelines which will be adopted in 2027. The following are some central considerations for a successful new agreement described by Udall.

The Upper Basin’s “Delivery” Obligation

Among the problems that stakeholders are aiming to resolve is the nature of the Upper Basin’s delivery obligations. There is a clause in the original Colorado River Compact that says that the Upper Basin shall not allow the flow of the river to decline below 75 maf every ten running years. However, it is not clear if this obligation is really a “delivery” obligation or if it is a “non-depletion” obligation. If it is a delivery obligation, that means that the entire reduction of flow coming from the Upper Basin due to climate change falls on the Upper Basin to solve. Clearly, this was not the intent of this clause in the original 1922 compact, and the Upper Basin states are making this argument.

Graphic credit: Chas Chamberlin/Water Education Colorado

Tribal Issues

Native American tribes are expected to have a much more significant role in the renegotiation of the Interim Guidelines than they have had in previous decision-making processes for management of the river. There are 29 tribes in the basin. Altogether, they have a right to control about 20% of the basin’s water. This right derives from a 1908 Supreme Court decision which issued the “Winters Doctrine.” This doctrine said that when the federal government creates a reservation of land for a tribe, implicit in that reservation is a water right.

However, tribal interests were still left out of the 1922 compact, and many of their rights remain unquantified. Even in the 21st century, the tribes in the basin were not invited to participate in the 2007 Interim Guidelines negotiations or the 2012 Basin Study. The 2019 DCPs were an important development in the inclusion of tribes in river management discussions after their needs and rights had been historically ignored. For the first time, these 29 distinct tribes were acting collectively and were included in the planning process. The DCPs were also the first time that a tribe agreed to accept a monetary payment in exchange for using less than their full water right. Inclusion of tribal interests in the renegotiation of the Interim Guidelines is expected, and will be essential to the new agreement’s success.

The Structural Deficit

Fundamental to the dilemma faced by basin stakeholders in this renegotiation process is the “structural deficit.” This is, quite simply, an imbalance between the supply of and demand for water in the basin. Since 2000, demand has outpaced supply. Demand reductions are challenging because once a water user has access to a supply of water, it is difficult to get them to relinquish it. The supply-side is more challenging to address. In the absence of cooler temperatures and more precipitation ­– conditions increasingly unlikely as climate changes — it is difficult to create more supply. It is easier to change consumption patterns than it is to change the hydrology of the river. Without demand reductions in the Upper and Lower Basins, there is a high probability that the amount of water in the reservoirs will continue to fall.

Udall referenced a recent study that found that the Upper Basin’s water demand is unsustainably high. Despite this finding, parts of the Upper Basin actually want to increase their demand, which in the face of declining flows is an issue that will need to be addressed in the negotiation process. Demand Management measures, by which water users can voluntarily accept money in exchange for reducing their water consumption, will likely be part of the solution in the Upper Basin but caps on demand may also be necessary to ensure that the delivery obligation is fulfilled.

In the Lower Basin, the Central Arizona Project diverts water from the Colorado River into Arizona, providing water for an area including the cities of Phoenix and Tucson. As a part of the original agreement that permitted this project, it was agreed that if there ever was a shortage of water in the basin, Arizona would bear the brunt of demand reductions. Demand reductions will likely be necessary in the Lower Basin but Udall noted that it would be difficult in practice to mandate that they all come from Arizona. Solving this dilemma will be a part of the new Interim Guidelines negotiations. One method that may be used is to begin charging evaporative losses to state water budgets in proportion to their use. Currently, evaporation is being charged to nobody, which is a part of the overuse problem.

Guidelines for Successful Renegotiation

Udall also identified other steps that can be taken by stakeholders to work toward a successful new set of interim guidelines. First, he emphasized the importance of good science. Realistic climate and hydrological modelling are necessary to inform the negotiations. Udall noted that many of the models being used by watershed states are overly optimistic with regard to future hydrology. Beginning the negotiations with inaccurate presumptions about the future of the watershed are setting the new agreement up for failure. While the renegotiation is a political process, it needs to be informed by most accurate scientific information possible.

Because the structural deficit is a basin-wide issue, Udall advocated for the use of a combined metric that adds the quantity of water in Lakes Mead and Powell. This would be a more accurate way to gauge water shortages because the water in the reservoirs individually is less important than the total quantity between them when informing the management of the entire river basin. He also said that using clear language in negotiations is critical. For instance, one should never inaccurately say that the Colorado River Compact itself is being renegotiated. It is only the Interim Guidelines that are being replaced; the Compact remains the foundation for the river’s allocation.

The renegotiation process is more than just a group of stakeholders sitting around a table, working out a plan for the river. It is a series of large and small meetings, some more formal than others. Since not everything is negotiated in official sessions, there is room for behind-the-scenes discussion while also maintaining transparency. During the round table’s Q&A session, Udall mentioned that river management issues under discussion will be reported by many talented journalists, who will bring transparency to the process for interested parties.

Ultimately, the process of renegotiating the Interim Guidelines requires a balancing of political, economic, environmental, and societal values. Climate change is the defining issue of our time, and it is at the center of these water issues in the American West. While one can easily become disillusioned by political processes, especially in the realm of climate and environmental issues, Udall ended on a note of optimism. While the solutions are not all clear, there are good relationships among stakeholders, which will form a solid foundation for successful negotiations.

– Stephen Yaeger, RNRF Program Manager

The PowerPoint Udall used during his presentation can be found here.

In his presentation, Udall referenced a series of studies about the climate and hydrological conditions of the Colorado River. They can be found at the following links:

Increasing influence of air temperature on upper Colorado River streamflow

The twenty‐first century Colorado River hot drought and implications for the future

On the Causes of Declining Colorado River Streamflows

Unprecedented 21st century drought risk in the American Southwest and Central Plains

Large contribution from anthropogenic warming to an emerging North American megadrought

Colorado River flow dwindles as warming-driven loss of reflective snow energizes evaporation

When is Drought not a Drought? Drought, Aridification, and the “New Normal”

Alternative Management Paradigms for the Future of the Colorado and Green Rivers

Colorado River “Beginnings”. Photo: Brent Gardner-Smith/Aspen Journalism

Data Mega-Dump: Alfalfa (Part II) — @Land_Desk #ColoradoRiver #COriver #aridification

Hayfield in Orderville, Utah, irrigated with water from the East Fork of the Virgin River, a Colorado River tributary. Jonathan P. Thompson photo.

Click the link to read the article on the Land Desk website (Jonathan P. Thompson):

By now you may have heard that the Colorado River is in trouble, as are the 40 million or so people who rely on it and all the people (and livestock) that eat the crops it irrigates. It’s not the only Western river facing a crisis: The situation on the Klamath is dire and the Rio Grande pretty much dried up this summer, its demise delayed by an abundant monsoon.

The problem is simple: The collective water users are consuming more water than is actually in the river and its tributaries; that is, they are pulling about 14 million acre feet each year out of a river that only has about 12 million acre feet of water in it. And consumption continues to hold steady even as the river continues to shrink, drawing down reserves to a critically low level. 

Or to put it in the possibly more relatable terms of a household budget: Spending is remaining constant even as the household income shrinks. The household is running a deficit, in other words, which is rapidly emptying the savings accounts (Lakes Mead and Powell). And, on top of that, the household has outstanding debts (to tribal nations whose senior water rights have yet to be developed, honored or even quantified). The accountants have tapped into retirement accounts (Upper Basin reservoirs such as Flaming Gorge and Blue Mesa) and imposed temporary cuts (Tier 1 and 2a Shortages) to shore up the savings accounts, but it isn’t enough. 

Spending must be dramatically and permanently slashed to better-than-sustainable levels, now, to avert crisis, allow the household to start building back its savings—and, finally, to settle those outstanding debts. 

Which is why Bureau of Reclamation Commissioner Camille Calimlim Touton told the collective water users in the Colorado River Basin states that they needed to figure out how to cut 2 million to 4 million acre-feet of consumption, per year. That’s a whopping amount (Arizona’s total use is less than 2.8 million acre-feet per year). And it may not even be enough. The lower end of those cuts will just about solve the deficit spending, but it won’t be adequate to build up the savings or to settle outstanding debts. If climate change continues to shrink the river even 4 million acre-feet may not be enough. 

So, we—the Colorado River users—must make huge cuts. And that means the biggest users of water (the biggest spenders, to go with our earlier analogy) are going to have to play a major part. The biggest user is agriculture and the thirstiest crop is hay, alfalfa in particular. For High Country News’s Landline I wrote about alfalfa and the need to grow less. This Data Dump is intended to provide some more data to support and supplement that piece. Some of it you’ve seen in previous Data Dumps, but some of it will be new. 

But first, a note: I’m not making value judgments here, nor am I “vilifying” a particular crop, as one reader suggested. I’m not saying that alfalfa is somehow less valuable or more wasteful than almonds, or golf courses, or even your daily shower. Remember that alfalfa not only feeds beef cattle, but also dairy cattle (I can’t find reliable stats on how much alfalfa goes to beef vs. dairy—if anyone knows, please tell me!). So if you eat cheese or butter or ice cream, all of which are high on my list of yummy foods, you’re probably eating alfalfa. Nor am I saying that we need to fallow alfalfa fields instead of drying up golf courses or anything else (if it were up to me golf courses and turf lawns would be banned long before alfalfa, and canals covered with solar panels before alfalfa fields).

Cuts are going to have to come from across the board and across every sector. It’s just that as the biggest water user in the Colorado River Basin, alfalfa must play a part (it’s just math). And according to federal agricultural data, farmers are growing less alfalfa in the Colorado River Basin than they were five years ago. That is certainly a beginning. 

Now, on to the numbers. For reference: 1 acre-foot = 325,851 gallons. Most of the stats come from the U.S. Bureau of Reclamation and the U.S. Department of Agriculture’s Farm Service Agency, National Agricultural Statistics Service, Foreign Agriculture Service and Census of Agriculture.

“Natural Flow” is a calculation of how much water would flow in the Colorado River without any withdrawals or reservoir evaporation. In other words, it’s the amount of water available for use. The 1922 Colorado River Compact assumed that there would be at least 15 million acre feet running past Lee’s Ferry. Over the last two decades it’s averaged in the 12 MAF to 13 MAF range—and falling. Source: USBR
For the life of me, I cannot find a more updated version of the breakdown of consumptive uses in the entire Colorado River Basin. The USBR has Consumptive Use and Losses reports for the Upper Basin up to 2020 (see below); and “accounting reports” for the Lower Basin, which break use down by irrigation district, but not sector. So I’m relying on this. (If any readers have more up to date breakdowns, send them my way!). Total consumptive use has dropped to between 13 million and 14 million af and agriculture continues to use the lion’s share of the water. Source: USBR.

2 million to 4 million acre-feet Amount of additional cuts—on top of those already made this year and last year under the emergency shortage declarations—Colorado River water users need to make to bring consumption in line with water supplies. That’s enough to fill 1.8 million to 2.2 million Olympic-size swimming pools; or 222,222 Kim Kardashians-worth (see data point below).

244,635 acre-feet Amount of Colorado River water Nevada is forecast to use this year, nearly all of which goes to Las Vegas and neighboring cities. The state’s water users withdraw about 450,000 acre feet from Lake Mead, but then return about 230,000 acre-feet in the form of treated wastewater via the Las Vegas Wash.

39 Number of golf courses in Las Vegas

459 acre-feet Average annual water used to irrigate a golf course in the Southwest, according to the U.S. Golf Association. 

300 Number of golf courses in Arizona, according to Golf Arizona.

921 Number of golf courses in California.

3.18 million gallons per acre (9.76 af) Amount of water needed per year to keep grass alive in the Mojave Desert. That’s about twice as much as what alfalfa requires.

13,455 square feet Size of an Olympic-size swimming pool, which holds 1.8 acre feet of water.  

600 square feet Maximum size of a swimming pool in Las Vegas’ new building code, which SNWA says will save 32 million gallons of water over the next decade. 

470 square feet Average size of a Las Vegas residential swimming pool, but some are over 3,000 square feet. 

2.2 million Approximate number of residential swimming pools of all sizes in the seven Colorado River Basin states.

232,000 Gallons of water over the maximum limit Kim Kardashian used at her L.A. property in June (about .7 acre-feet). If she were to continue that rate of excessive use she’d consume about 9 acre-feet per year—or twice as much as alfalfa.

145 million gallons Daily consumptive water use of power plants in Colorado River Basin states, which amounts to about 162,000 acre-feet per year. 

Okay, those numbers are there to give some perspective, and to show that, yes, golf and lawns and soccer and football fields and coal power plants and Los Angeles celebrities use a bunch of water. And now let’s look at alfalfa:

This is the breakdown of water use for the Upper Basin (Colorado, Utah, Wyoming, New Mexico) only. Agriculture guzzles the lion’s share of the water, as you can see. You may also notice that the Upper Basin uses less water than California, alone. That may seem unfair, but it’s how the Colorado River Compact was set up: The Upper Basin states aren’t guaranteed a set amount, they just get what’s left over after delivering 7.5 MAF per year to the Lower Basin. Lately that has not been very much. USBR.
The Imperial Irrigation District is by far the biggest single water user on the Colorado River, consuming about 850 billion gallons per year, nearly all of which is used for agriculture in the Imperial Valley. As much as one-third of that water was used to irrigate alfalfa, based on 2017 USDA agriculture census figures. *This figure for the Southern Nevada Water System does not account for Las Vegas Wash return flows, which are subtracted from this amount (to arrive at a net total of about 245,000 af). USBR.

2 to 6 acre-feet
Amount of water needed annually to irrigate an acre of alfalfa, depending on location and climate. In Colorado’s San Luis Valley alfalfa consumes about 2 acre-feet per year, while in California’s Imperial Valley it can be a bit more than 6 acre-feet annually. Most other places fall somewhere in between.

4.1 million Acres of irrigated agricultural land in Utah, Arizona and Colorado in 2017.

2.7 million Acres of irrigated agricultural land in those three states planted with alfalfa and other hay crops.

3 million Acres of irrigated agricultural land in Western states (including the Colorado River Basin) planted with alfalfa grown for forage (hay), grazing or seed in 2022.

18,000 acres Amount of land planted with alfalfa in in San Juan County, New Mexico, in 2022, all of which relies on water from Colorado River tributaries for irrigation.

76,070 acres Amount of land planted with alfalfa in the San Luis Valley in Colorado in 2022. Fields here are irrigated with water from the Rio Grande, which dried out in Albuquerque this year.

85,795 acres Amount of land planted with alfalfa in Imperial County, California, this year, consuming as much as 510,000 acre feet of Colorado River water—more than twice as much as the entire Las Vegas metro area’s yearly consumptive use. Imperial County has come to be known as the hottest county in the nation.

139 Number of Imperial County farms on which more than 500 acres of alfalfa was grown in 2017.

88,252 acres Amount of land planted with alfalfa this year in Maricopa County, Arizona, home of Phoenix.

90,000 acres Amount of photovoltaic solar panels needed to equal the generating capacity of Diablo Canyon nuclear power plant, according to a 2021 MIT/Stanford study.

1.73 million metric tons Amount of hay shipped overseas via San Francisco and Los Angeles ports in 2021. This amounts to 50 million gallons of water, according to rough calculations based on 240 lbs of water/ton of hay.

$880 million Value of last year’s hay exports from Colorado River Basin states.

$450 million Value of that hay that went to China. 

$73 million Value shipped to Saudi Arabia.

75% Portion of Utah’s Colorado River use consumed by agriculture in 2018.

446,000 acre-feet Estimated amount of water that evaporates annually from major Upper Basin reservoirs, including about 359,000 acre-feet from Lake Powell.