Standing atop Hoover Dam, peering over the chain-link fence down its 726-foot concave face of concrete, you simply feel impressed. The dam tamed the Colorado River’s floods and created a reservoir, Lake Mead, able to hold 26.1 million acre-feet of water, not quite two years of annual flows, when full at an elevation of almost 1,220 feet.
But Lake Mead has been nowhere close to full for most of the 21st century. The widening “bathtub ring” of white in the once-black, volcanic rocks of Boulder Canyon documents the reservoir’s 190-foot fall. Despite a rambunctious runoff from the previous winter’s snowpack in the Rocky Mountains, the reservoir was 61 percent empty by mid-August 2019. The U.S. Bureau of Reclamation that same month projected the reservoir would be below 1,090 feet on January 1, 2020. That finding triggered the first-ever delivery cuts to Arizona, Nevada and Mexico under the Lower Basin Drought Contingency Plan, or DCP, signed by the basin states in 2019.
It’s a new era in the lower Colorado River Basin. The 20th century was one of engineering triumphs, ever more straws inserted into the river in defiance of geography and the innate aridity of the lower basin, the region below Lee Ferry, Arizona. This includes portions of Arizona, Nevada and California along with the Mexican states of Sonora and Baja California but also tribal lands, sovereign yet part of the United States. Water stored in Mead and other vessels gives Las Vegas Boulevard its fountains and faux falls, grocery stores across the country a reliable delivery of broccoli, lettuce and spinach in mid-winter, and Phoenix, San Diego and other metropolitan areas their prosperity.
Now comes a period of cutting back, pinching water deliveries for a time or perhaps forever. The first rude shock of this new challenge arrived during the first four years of the 21st century, the river delivering only 63 percent of what was then defined as normal at Lee Ferry. During the same period, in 2003, then-Interior Secretary Gale Norton ordered annual Colorado River deliveries to California cut to 4.4 million acre-feet, the state’s legal apportionment under the Boulder Canyon Project Act of 1928. The state had been taking 5.3 million acre-feet. It did so because it could. Nobody was being shorted, save for the river’s delta at the Gulf of California, which has not reliably seen water since the 1960s.
The Bureau of Reclamation then began working with the seven U.S. basin states to develop a plan if water-short years continued. The result in 2007 was the Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lakes Powell and Mead. By identifying cuts in water deliveries to the lower basin keyed to reservoir elevations, the guidelines aimed to keep Mead from falling to worrisome levels. At 1,075 feet, the crisis would become real and deliveries to Arizona and Nevada would be cut. Those cuts deepen at 1,050 feet, when Mead is at 29 percent of capacity and hydroelectric production at Hoover Dam ends. More cuts come at 1,025. At elevation 895, Mead can no longer release water downstream. It’s called dead pool.
Water levels in Mead have flirted with but never crossed 1,075, the trigger for a shortage declaration under the interim guidelines. In 2013, after two years of exceptionally low flows, the Bureau of Reclamation and the seven states agreed an additional cushion was needed. That’s what the Lower Basin DCP provides, with cuts to lower basin states beginning sooner, at 1,090 feet, and greater cuts at lower elevations.
The Lower Basin DCP can be seen as part of the broader Colorado River DCP and a 2017 agreement called Minute 323 that was tacked onto the 1944 U.S.-Mexico water treaty, committing Mexico to deeper shortage sharing.
Two giant issues still loom, unresolved by the DCP. First, it does not address what experts call the “structural deficit.” Lower basin states have been using 1.2 million acre-feet annually more than the river delivers on average. Evaporation and system losses are not assessed against the lower basin.
Second, the river will likely deliver even less water in the future. Rising temperatures have been robbing the river of water, part of a climatic shift with no end in sight.
Belt-tightening identified in the DCP, though temporary, should suffice until a broader reassessment of Colorado River operations is completed. The DCP and interim guidelines expire in 2026, by which time a new river management plan will likely be in effect.
Of the lower basin states, Arizona has the most at stake in keeping Mead above crisis level. The Colorado River Compact apportions the state 2.8 million acre-feet annually, dwarfing Nevada’s allocation of 300,000 acre-feet. The Colorado River provides nearly 40 percent of Arizona’s water.
The Central Arizona Project, or CAP, delivers 1.6 million acre-feet, more than half of the state’s Colorado River supply. In 1968, when authorizing CAP funding, Congress conceded California’s demand that CAP water be junior in priority to California. That means CAP users take shortages first if Mead levels decline.
Before signing the DCP, Arizona had to develop an intra-state plan. It was a pained but ultimately self-affirming experience. Arizona began its discussion in 2015 but got little done amid internal squabbling. Then a good snow year in the Rockies caused Mead to rise. One CAP director even wondered publicly whether planning for future shortages was necessary. That myopia was dispelled by the winter of 2017-2018. It was the fifth-driest year on record, with flows from the upper basin, source of 92 percent of the river’s water, just 41 percent of average. As Arizona dithered, Reclamation Commissioner Brenda Burman warned that if Arizona and other states didn’t take action by January 31, 2019, her agency would.
With a hard deadline and a sharp decline in river flows, Arizona’s major water agencies, the Arizona Department of Water Resources and CAP, coalesced by June 2018 to lead a transparent and inclusive 42-member task force. The result was 14 distinct agreements that together constitute compromises, payments, and water transfers to reduce use, some temporarily and others permanently. Then Arizona legislators had to approve their state’s drought contingency plan.
“It was emotionally charged, because not everybody was going to be pleased,” says Rosanna Gabaldón, a state representative whose district straddles Tucson and rural areas. For a time, Gabaldón doubted Arizona could agree on a drought package. But the legislation was signed with six hours to spare. Upon her review, Burman said both Arizona and California hadn’t completed their work, but they met her extended deadline of March 4.
Arizona’s cuts come almost entirely from the 1.6 million acre-feet pumped from the Colorado River through the CAP. CAP’s 336-mile canal crosses Phoenix and Tucson and reaches farmers in Pinal County, between the metropolitan areas. In 2020, because the Bureau of Reclamation’s August 2019 24-month study projected Lake Mead to fall below 1,090 feet by January 1, 2020, Arizona this year will take 6.9 percent less, or a 192,000 acre-foot cut. If Mead drops to 1,075 feet, as remains distinctly possible, Arizona could lose up to an additional 512,000 acre-feet, though some of that water could be recovered at a later date if storage recovers. At 1,025 feet, it cuts back up to 720,000 acre-feet, or nearly 26 percent of its Colorado River water.
Cities fare well enough in this squeezing exercise. Phoenix and six of its suburbs will see successive cuts beginning at Mead elevations of 1,075 feet. For Tucson, the spigot tightening begins at 1,045 feet and tightens even more at 1,025. However, only if Lake Mead falls to 1,000 feet would Tucson possibly have to cut water sent to homes or businesses.
Agriculture takes Arizona’s biggest hit. That was expected. If agriculture was the primary argument for the CAP in the 1960s, it had the lowest priority among the contracts. This use is almost entirely in Pinal County. Flat and mostly rural, most drivers on Interstate 10 between Phoenix and Tucson hurry through it. The county’s 200 farms produce 45 percent of Arizona’s cattle, 42 percent of its cotton and cottonseed, and 39 percent of its milk, according to a study commissioned by Pinal County irrigation districts. Cities were unimpressed. The total economic output of these Pinal County farms, they pointed out, was half that of the state’s golf courses.
Groundwater was the sole source of water in Pinal County from 1940 to about 1990, when CAP water arrived. Farmers, though, couldn’t repay even the subsidized costs of CAP’s capital-intensive infrastructure. In 2004, they agreed to a shorter-term contract for Colorado River water while being relieved of infrastructure costs. This lower-priced water is also subject to availability, however. Irrigators were already scheduled to stop receiving CAP water entirely by 2030. The plan was for farmers to then return to exclusive groundwater use. Arizona’s DCP will cause the farmers to lose a third of their water in years 2020-2022 and lose deliveries altogether in 2023, seven years earlier than previously scheduled.
Arizona’s compromise yielded the Groundwater Infrastructure Fund, which identifies $50 million—$20 million of it state money—for Pinal County farmers to finance new groundwater-pumping infrastructure. Not all legislators supported the aid.
“But many of us drew the line at funding groundwater-pumping infrastructure, which to us was going backwards. The last thing we should be doing is returning to depleting our groundwater aquifers”, says Airzon State Rep. Kirsten Engel, a Democrat from the Tucson area.
Will this cause farmers to pump groundwater below Pinal County to extinction? Probably—assuming that Lake Mead continues to sag. Application of Colorado River water across the cotton and alfalfa fields allowed the aquifer to rise to nearly 1940 levels. With no river water percolating into the aquifer, it will inexorably decline. Other, less thirsty crops have been getting attention: industrial hemp and a shrub called guayle, which produces an alternative to rubber. But these conversations occur in the margins.
New conservation efforts, including those in agriculture, will benefit from $2 million appropriated by state legislators. Arizona Gov. Douglas Ducey also replaced a council focused on water augmentation with one responsible for studying innovation and conservation.
New political strength of tribes, particularly those in Arizona, was evident in the drought contingency planning. Arizona tribes get 12.5 percent of the state’s water directly from the Colorado River and another 17.5 percent of CAP water. The Gila River Indian Community alone has 311,000 acre-feet, the largest single contract for CAP water. Their reservation just south of Phoenix was created in 1859, giving it the highest priority. The intra-Arizona DCP gives the Gila River Indian Community $92 million for 200,000 acre-feet lost in the DCP’s seven-year life. They also lose additional water that tribal officials value at $30 to $50 million. For the Gila River Indian Community, the DCP negotiations were something of a coming-out party. With European settlement, the tribe was dispossessed of their water until the Arizona Water Settlement Act of 2004 allowed the tribe to use water rights that had previously existed only on paper. Even so, the Gila were not invited to be at the table at the outset of DCP planning. “Tribes have to be at the policy table,” said Governor Stephen Roe Lewis. Now, they definitely are.
The Colorado River Indian Tribes—consisting of four distinct tribes, the Mohave, Chemehuevi, Hopi and Navajo, with a reservation that stretches along the Colorado River in Arizona and California—also played a significant role. They divert nearly 600,000 acre-feet directly from the Colorado River at the border between Arizona and California, with priority dates from 1865-1874. “This is not CAP water. It is not subject to being cut. It is the highest priority water in the lower basin,” explained Margaret Vick, special counsel to the Colorado River Indian Tribes, at the June 2019 Getches-Wilkinson Center Summer Water Conference at the University of Colorado-Boulder. After a history of being taken advantage of, the tribes are now “partners with the state legislative leaders,” she said.
The four tribes agreed to take 10,000 acres of farmland out of production for three years, allowing the water to instead remain in Lake Mead. In return, the tribes receive $38 million, including $30 million from the state and $8 million from the Environmental Defense Fund and the Walton Family Foundation.
“I don’t think Arizona could have met their requirements without the water that the tribes put on the table,” says Larry MacDonnell, an adjunct law professor at the University of Colorado-Boulder and a member of the Colorado River Research Group.
California has different tensions. The state has more Colorado River water, 4.4 million acre-feet, the majority of it claimed for agriculture prior to the Colorado River Compact.
About a quarter of southern California’s water comes from the Colorado River. Metropolitan Water District of Southern California delivers this Colorado River water, along with water imported from northern California, to smaller agencies that collectively serve 19 million people. Metropolitan’s basic annual apportionment of Colorado River water is 550,000 acre-feet, and it gets about 400,000 of additional Colorado River water through transfers and exchanges, largely from irrigation districts. Under the DCP, if Lake Mead drops below 1,045 feet, California will contribute between 200,000 and 350,000 acre-feet of water a year, depending on the lake’s elevation. Because of the wet year in 2018-2019, Reclamation estimates a less than 10 percent chance that the reservoir will fall to that level by 2026.
California’s contribution under the DCP is shared by two of the state’s three big irrigation districts and Metropolitan. Initially, the Imperial Irrigation District (IID) was also planning to participate. It conditionally approved the plan in December 2018 but in March 2019, just before a federal deadline, IID decided it would not support the DCP as negotiated because one of its conditions—federal funding for the Salton Sea—had not been satisfied. Metropolitan’s board of directors voted to contribute an additional 250,000 acre-feet to Lake Mead if necessary to cover the Imperial Irrigation District’s portion. But these contributions are not permanent. Metropolitan, along with others in California, Arizona and Nevada, can in the future withdraw water left in Lake Mead under a provision in the 2007 guidelines called “intentionally created surplus,” or ICS.
ICS water is made through projects that create water system efficiency, conservation, or even importation of water into the Colorado River Basin. ICS water temporarily augments reservoir levels but is then available for later drafting by whomever contributed it. The Bureau of Reclamation reported provisionally that in 2018 Nevada had 700,448 acre-feet, California 698,432 acre-feet, and Arizona 343,052 acre-feet of ICS water stored in Mead.
This water might better be understood as a savings deposit. Metropolitan has stored and withdrawn water three times. But what if an entity wants to withdraw when those savings are most desperately needed? Imagine the scene from the movie “It’s a Wonderful Life,” when the panicked townspeople of Bedford Falls show up at the savings and loan, demanding their C-notes.
Brad Udall, senior scientist and scholar at Colorado State University, told a U.S. House subcommittee in February 2019 that this illustrated an implicit flaw in the concept. “These water storage efforts allowed us to push the problem forward in time, hoping Mother Nature will rescue us,” Udall said.
Bill Hasencamp, manager of Colorado River resources for Metropolitan, says his agency’s savings balance is responsible for about a 12-foot increase in Mead—contributing significantly to keeping the reservoir out of shortage. But he agrees that the savings device is not the long-term answer to the oversubscribed Colorado River Basin. “Eventually we have to make some permanent cuts in the lower basin, and that’s what we’re gearing up for in 2026 negotiations,” Hasencamp says.
More tension revolves around the shrinking Salton Sea, located 125 miles northeast of San Diego. It’s an ancient sea bed, below sea level, and filled sporadically through the ages by the Colorado River as it wandered on various paths toward the ocean. Its current iteration dates to 1905, when the river wrestled free of an attempt to channel it into orderly submission. It’s a shallow, salty marvel with twice the surface area of Lake Tahoe that also serves as a major stop for migrating birds, some listed on state and federal endangered and threatened lists, along the Pacific Flyway.
Water levels were sustained by 1.3 million acre-feet of annual runoff from Imperial Valley farms until 2003, when the Imperial Irrigation District began transferring water saved through conservation measures to San Diego County, Metropolitan, and the Coachella Valley Water District. The sea has fallen 9 feet since those transfers began, the saline water lapping onto shore at 237 feet below sea level in July 2019. As it does, the Salton becomes saltier, some 4 million tons of salt arriving through farm runoff each year, increasing the salinity 1 percent annually.
The Pacific Institute’s Michael Cohen, whose work for the past 20 years has focused on revitalizing the Salton Sea, identifies two problems. First is the decline of the sea in size and in its capacity for sustaining fish. It has dramatically fewer fish than 20 years ago, which in turn sustain resident and migratory birds. Birds have also lost roosting and breeding habitat.
A second issue is the human health impact of the wind blowing chemical-laden dust from the receding shores. The 650,000 residents of the Coachella and Imperial valleys already had a high incidence of asthma. The American Lung Association gives Imperial County an “F” score in high ozone and particulate pollution. The county seat, El Centro, is ranked eighth worst among 203 metro areas across the country for annual particle pollution. As transfers from irrigation districts to cities ramp up in the next decade, Salton Sea levels are expected to drop another 15 feet or so, exposing more toxic dust and more chronic respiratory issues. The shoreline by then will have receded 5 miles since 2003.
A 10-year Salton Sea mitigation plan, approved in 2017, has had stubby financial legs. To implement the phase-one plan requires $400 million, of which $300 million has somewhat belatedly been secured. That’s just the start of a longer-term plan for wetlands restoration and other mitigation.
For the Imperial Irrigation District, mitigating Salton Sea problems became the defining issue in the DCP. The district has legal rights to 18 to 20 percent of all Colorado River Basin water, 3.1 million acre-feet altogether, including use of 2.68 million acre-feet pre-compact, as of 2019. District directors in December voted to support the overall DCP framework. However, that support was contingent upon the federal government delivering $200 million for Salton Sea remediation.
Led by Metropolitan, California supported the DCP without the provision of contingency upon the federal funding. In March, Imperial sued Metropolitan and three other water districts, citing absence of a thorough environmental review of the drought plan. “Just as it is hydrologically connected to the Colorado River, the Salton Sea is inseparable from the DCP, and any attempt to sweep it aside or pretend it doesn’t exist is as unsustainable as it is cynical,” said Erik Ortega, president of the district, in a March 1 statement. “We all need to cross the finish line together, in California and across the two basins, but that won’t happen by taking shortcuts, environmental, economic or otherwise.”
In April 2019, on the day President Trump signed the DCP into law, Imperial asked a California court to suspend approvals of the lower basin DCP until after an environmental analysis was completed. With that, California, the lower basin, and all seven basin states moved forward on the DCP without the Imperial Irrigation District and without solving the problem of the Salton Sea.
Mexico is also part of the Colorado River Basin, apportioned 1.5 million acre-feet annually by the 1944 Mexican Water Treaty. It, too, is a partner in the effort to keep Mead from declining. A 2012 binational agreement specified that a shortage declaration under the 2007 interim guidelines would reduce deliveries to Mexico of up to 125,000 acre-feet. That agreement, Minute 319, also produced the historic 2014 pulse flow that used Mexico’s water stored in Lake Mead to wet the delta for the first time in 16 years. Minute 319 has since been supplanted by Minute 323. Signed in 2017, Minute 323 authorizes Mexico to continue storing water in Lake Mead and also commits the United States to financially support water efficiency projects in Mexico with the goal of leaving 200,000 acre-feet of water in Mead to benefit both countries. It also requires both countries to provide water and funding for delta habitat restoration.
Looking forward, Jennifer Pitt, director of Audubon’s Colorado River Program, sees need to build on existing binational relationships. “I think Mexico has already demonstrated that they are willing to be a partner in the equitable distribution of shortages, and I don’t think we should expect any different,” she says. Equitable, she believes, means proportionate to the shortages absorbed by the lower basin states.
Both the DCP and Minute 323 will expire in 2026. Negotiations between the U.S. and Mexico to determine what comes next after Minute 323, the DCP, and the interim guidelines, “will be tied to their implementation and operating experience [of Minute 323] between now and then,” Pitt says.
Minute 323 identifies specific projects but has no provision for another pulse flow. Pitt sees the river delta being like the Salton Sea: undeniably a part of the Colorado River Basin. The drying of the delta was the first visible signal of water imbalance.
Doing something about it means finding water to create a more resilient ecosystem that can address the habitat needs of birds that used that area as part of their migration path, she says. That this ecosystem is in Mexico also matters. “If the restoration effort were to be abandoned, we don’t know if Mexico would be as willing to share in the shortages with other water users,” Pitt says.
Even before the DCP was signed in May 2019, eyes were already on replacement of the interim guidelines and the DCP. It poses a greater challenge yet. The word “drought” probably should be discarded in the 2026 document’s title because the big overlapping issues of climate change and structural deficit that it must address are broader. “Hard issues left unresolved by the DCP will make the coming negotiations even more challenging,” said Udall in his February testimony to the U.S. House subcommittee.
But the DCP also marks several major achievements. The work was more inclusive, more deliberate in bringing tribes and environmental groups to the table, both of them often overlooked or strictly adversarial in the past. Even where it failed, there was success, as the Colorado River Research Group, in a May 2019 paper, pointed out: “Two of the most problematic features of the current management framework—the inability of Pinal County, Arizona, farmers to easily absorb CAP curtailments, and the environmental and public health challenges associated with limiting Salton Sea inflows—have influenced, and are influenced by, matters that were heretofore considered outside of basin water management planning.”
Too, the DCP carved a path, concrete in its details and immediate in its consequences, to reconcile reality with diversions. Based on the plan’s provisions, the Bureau of Reclamation in August 2019 ordered reduced deliveries to Arizona of 192,000 acre-feet and to Nevada of 8,000 acre-feet in 2020. In addition, under its supplemental treaty agreement, Mexico gets 41,000 acre-feet less. Those cuts were based on projections that Mead’s water would be below 1,090 feet, the new cushion level, on January 1, 2020. That water must remain in the reservoir until Mead rises above an elevation of 1,100 feet. These are the first, marked acknowledgements of the 21st century hydrologic realities.
In Arizona, David White, deputy director of the Julie Ann Wrigley Global Institute of Sustainability at Arizona State University, sees the template that emerged dwarfing the details in importance. “That was a very big win for the state,” says White. Creating an open, transparent process for figuring out how to apportion cuts was vital.
The Arizona Republic was of a like mind. “Let’s be clear. This deal isn’t perfect. It’s costly and painful, and it solves exactly zero of our water problems,” it wrote in a January 31, 2019, editorial. “All DCP does is buy us time. But it showed us how to solve our problems and move forward in a drier future.”