California Can Solve the Colorado Water Deficit

I was a dam builder
Across the river deep and wide
Where steel and water did collide
A place called Boulder on the wild Colorado
The Highwayman, lyrics by Jimmy Webb

When the Hoover Dam was completed in 1935 it was the largest dam in the world, creating what was to become the largest reservoir in the world, Lake Mead. It took six years to fill, but at capacity Lake Mead held 28 million acre-feet (MAF) of water. Mead’s upstream counterpart, Lake Powell, created by the Glen Canyon Dam and completed in 1963, delivered an additional 25 MAF of storage capacity.

These massive dams bottled up some of the last downstream extremities of the Colorado River watershed, where mountainous topography permits large reservoirs. The Colorado River, 1,400 miles in length, drains a whopping 250,000 miles of watershed. Its tributaries extend eastward through Arizona and New Mexico into headwaters in the San Juan Mountains of southern Colorado, and north through Utah and Colorado up to headwaters in the Wind River Mountains of Wyoming. Access to the water stored in these giant reservoirs made possible the growth of cities and agriculture from the California coast all the way to Tucson in southeast Arizona. Las Vegas and Phoenix would not exist if it weren’t for these dams, nor would nearly 500,000 acres of rich irrigated farmland in California’s Imperial Valley along the border with Mexico.

Today the benefits of Lake Mead and Lake Powell are imperiled. For the first time since these reservoirs were built nearly a century ago, the relentlessly escalating quantity of water demanded by the cities and farms of the Southwest, combined with years of drought, have brought the levels of remaining water to dangerous and unprecedented lows. As of mid January 2023, only 7.4 MAF remains in Lake Mead, and only 5.6 MAF remains in Lake Powell. These trends are alarming.

For the last several years, far more water has been withdrawn from these reservoirs than was recharged by river flow. Measuring the flow of river water reaching the lower Colorado each year offers clarity on just how much has changed on the supply side. When these dams were built, and well into the 1980s, the average annual flow of the lower Colorado was over 20 MAF per year. An authoritative study conducted by the Department of the Interior in 2012 calculated that the average annual flow had dipped below 15 MAF per year around 2000, dropping as low as 12 MAF in 2008. A more recent analysis published by the Water Education Foundation in December 2022 reports “the river’s average flow since 2000 has been 12.3 million acre-feet.” In 2021, gripped by an ongoing drought, Colorado Basin natural flow plummeted to 6.7 MAF, only recovering to 9.9 MAF in 2022.

Average water use when Lake Mead was full back in the early 1940s was 7 MAF per year, rising to 12 MAF per year when Lake Powell was completed in the 1960s. For the last 20 years, average annual water use has plateaued at around 15 MAF per year.

It doesn’t take a hydrologist to take these numbers and project a dire scenario. With annual demand currently at 15 MAF, and annual supply dwindling to 12 MAF, and less than that in the last few years, even big reservoirs such as these are going to lose big gulps of water every year and eventually go dry. That is exactly what’s happening. Both lakes are now approaching the so-called “minimum power pool,” where the water level is too low to flow through hydroelectric turbines, or even “dead pool,” where the level has fallen so far that there are no large conduits placed low enough on the dams to allow a useful volume of water to be released.

This is the brink on which we stand today. Notwithstanding the complex balancing act whereby Lake Powell upstream can release water, so long as it has enough, to keep levels in Lake Mead from dropping to critical levels, for the last several years neither lake has been getting enough new water from natural flows. After years of supply deficits of around 3 MAF per year, any further drop in the water levels in either lake will take away their capacity to release any water beyond whatever natural flows enter the reservoirs from upstream.

Conservation Alone Is Not a Permanent Solution

To manage water scarcity, according to the prevailing wisdom among water bureaucrats and environmentalist activists, water must be used more efficiently. But for the most part this has already been done. For example, at the same time that annual water use from the lower Colorado has been relatively stable at 15 MAF per year, the population of Las Vegas has grown from 1.3 million to 2.9 million. The population of Phoenix has grown from 2.9 million to 4.7 million, and the population of Tucson has grown from 723,000 to just over 1 million. During this same period, from 2000 to 2020, irrigated farm acreage in Arizona has remained stable at just under 1 million acres, as has agricultural water use at just over 4 MAF per year. Through increased efficiency, Arizona’s farmers have achieved this while significantly increasing yields of some of their primary crops. Average alfalfa yields, for example, now accounting for over 300,000 acres of irrigated farmland in Arizona, have risen in the last 20 years from 7 tons per acre to 9 tons per acre.

As the supply of water from the Colorado River dwindles, farm acreage will inevitably shrink. But simply accepting a drastic and permanent cutback in farm acreage in places such as Arizona and California’s Imperial Valley ignores many negative consequences. Growing food in an arid environment may seem wasteful, but this ignores the quantity of still intact wildland and rainforest around the world that will give way to the plow to replace the food that will be lost if that land is taken out of production. If water can be found to keep Arizona and Southern California farmers feeding the world, how much land will be saved somewhere else? As it is, farmers in the American Southwest have become expert at surface drip, subsurface drip, micro-sprinklers, and trickle irrigation. Center-pivot sprinkler irrigation systems are timed to operate when evaporative losses are minimized. Traditional gravity-based flood irrigation is already largely reserved for acreage where the water will reduce salinity and recharge ground aquifers.

Because so many water-efficiency practices are already established, new restrictions on urban water use and major reductions in farm acreage might eliminate the supply deficit but would require punitive levels of rationing on urban residents and create undesirable ripple effects on the national and global farm economy. Even as water planners cope with the immediate crisis, a new sense of urgency should be directed toward building new water-supply infrastructure. Of all the states that could solve this regional problem, California is best positioned to make a difference.

How California Can Solve the Colorado Water Deficit

California imports up to 5 million acre-feet per year from the Colorado River via the Colorado Aqueduct, constructed in 1933. In a crisis, even with senior water rights, California could lose some of that allocation. And California faces a similar crisis with its groundwater, heavily relied on by farmers and heavily overdrafted (for years, more water has been withdrawn than replaced), as well as with its reservoirs, depleted after years of drought. But California has options.

As we have just seen this winter, as well as in the late fall of 2021, even during multi-year droughts, tens of millions of acre-feet rain down onto California via “atmospheric rivers,” but most of the water immediately drains into the ocean. California also has an 840-mile border (not including bays or inlets) with the vast Pacific Ocean, where a limitless supply of ocean water could be desalinated to serve its coastal cities.

Despite all this potential, investments to increase California’s water supply have been incremental at best. But this can change, and if it did, not only Californians but the entire Southwest would benefit. Imagine how much easier it would be to balance the Colorado River supply deficit if Californians were no longer transporting 5 MAF per year out of the lower basin to serve Imperial Valley agriculture and Southern California cities.

From a cost perspective, most supply solutions are financially affordable but nonetheless quite expensive. For example, only about one-third of California’s urban wastewater is recycled. Construction costs to upgrade every water-treatment plant in the state that isn’t already turning sewage back into recycled water for landscaping or even for potable reuse would cost about $20 billion, and give back up to 2 MAF per year.

Desalination is another option, but it is roughly twice as expensive as wastewater recycling. For an estimated construction cost of $20 billion, about 1 million acre-feet of ocean water per year could be desalinated. While it is the most expensive option, desalination has the virtue of being a perennial supply of new water, impervious to drought. What other options are there?

In an era that may involve warmer and drier winters, with less rain and less snowpack, it is necessary to more efficiently harvest runoff from the storms that do hit the state. The traditional way to do this is via reservoir storage, but in-stream reservoirs — those behind a high dam directly blocking a river — cannot be allowed to fill from early storm runoff, because that would render them unable to prevent flooding if there are late spring storms. Then if late spring storms don’t materialize, there’s inadequate reservoir storage and another water shortage.

Off-stream reservoirs, by contrast, don’t block the flow of a natural river. They are typically constructed in arid valleys, and flood runoff is pumped into them during storm events. Using California’s proposed Sites Reservoir as an example ($4 billion for an annual yield of 500,000 acre-feet per year), off-stream reservoirs could capture and release 1 MAF per year for a construction cost of $8 billion. But absent the capacity to capture large volumes of storm runoff and move it into these reservoirs, where will the water come from?

A new proposal, the “Water Blueprint for the San Joaquin Valley,” authored by a coalition of San Joaquin Valley community leaders and regional water agencies, is a work in progress. The centerpiece of this proposal is to construct what are essentially gigantic French drains within channels created inside San Joaquin’s delta islands. By drawing fresh water from perforated pipes situated beneath a gravel bed in these channels, floodwater could be safely harvested from the delta during periods of excess storm runoff. Preliminary plans for this system estimate the cost at $500 million per 200-acre facility. The estimated capacity for two of these facilities would be 2 MAF per year or more, at a total cost of $1 billion.

The blueprint also relies on the construction of a central canal in the San Joaquin Valley to transport water from the harvesting arrays in the delta to underground storage. Aquifer storage capacity in the San Joaquin Valley is conservatively estimated at 50 MAF. The projected cost for this canal, including connections to the Friant-Kern, Delta Mendota, and California aqueducts, as well as facilities to recharge and recover water from the aquifers, is $500 million.

This idea has extraordinary potential. Its preliminary construction cost estimate of $1.5 billion to harvest and recover 2 MAF per year of delta runoff is a rough order of magnitude lower than any other possible solution.

Moreover, it may well be feasible to safely harvest more than 2 MAF from the delta every year. An authoritative 2017 study by the Public Policy Research Institute describes so-called uncaptured water, which is the surplus runoff, often causing flooding, that occurs every time an atmospheric river hits the state. According to the study, “benefits provided by uncaptured water are above and beyond those required by environmental regulations for system and ecosystem water” (emphasis added). The study goes on to claim that uncaptured water flows through California’s Sacramento/San Joaquin Delta “averaged 11.3 million acre-feet [per year] over the 1980–2016 period.”

For this to come from some of the most respected water experts in California is very encouraging: The average quantity of “uncaptured water” flowing through the delta that is “above and beyond those required by environmental regulations for system and ecosystem water” averages 11.3 MAF per year.

An environmentally friendly delta diversion project has several appealing aspects. Unlike the delta pumps, these extraction channels would not harm fish, nor would their operation alter the current of the delta, which brings the risk of saltwater intrusion. Their high capacity may make building the controversial Delta Tunnel unnecessary. Storing high volumes of water in San Joaquin Valley aquifers with a known capacity in excess of that of Lake Mead and Lake Powell combined would eliminate the need for more reservoirs while also making possible almost a limitless capacity to store water from wet years to use in dry years.

The Upside of Massive Investment in Water Infrastructure

The reason the government subsidized water projects during the great waves of dam and aqueduct construction in the 1930s and again in the 1950s and ’60s is because affordable and abundant water lowers the overall cost of living and doing business. It lowers the cost of food. It lowers the cost of housing. It lowers utility bills. This is an economic ripple effect that has no rival. Affordable and abundant water is a core enabler of economic prosperity.

Conservatives ought to appreciate the case for public investment in water infrastructure: Without spending on the front end on huge capital projects that smash the price equilibrium for water and make it affordable, there will be a greater need for government spending on the back end. Billions will instead have to be spent on an enforcement bureaucracy to ration scarce water, along with the enforcement hardware — such as dual residential meters to monitor indoor vs. outdoor use — and additional billions will have to be perpetually spent to subsidize low-income families that cannot afford their water bills, food, and housing.

Investing in abundance at the level of basic economic essentials — water, energy, and transportation infrastructure — is a traditional role of government. The problem with rejecting on principle the use of government funds to subsidize infrastructure is that it implies a preference for spending government funds instead on perpetual funding for the new bureaucracies that will enforce rationing and the permanent burden of subsidies for low-income families.

Equally, opposing government participation in funding water projects is to legitimize the inevitability of high prices and scarcity. Denying funding to create water abundance is to accept the premise that a middle-class lifestyle is unsustainable.

However heretical it may sound to conservative and libertarian ears, there is a case to be made that the WPA projects that gave America Lake Mead, the Colorado Aqueduct, and a host of other assets, long since paid for and which yield dividends to this day, were worthwhile investments. Perhaps if there were sufficient regulatory reforms, private investment could pay for enough new water-supply infrastructure to create affordable abundance. Don’t hold your breath. In the meantime, start moving earth. Start pouring concrete. The water is there. Let’s go get it.

This article originally appeared in the National Review.

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