How the Water Crisis in the West Renewed the Debate About the Effectiveness of Major Dams

The idea is this: Since two of the nation’s largest reservoirs — just more than 300 miles apart — depend on the same dwindling water source but are each less than half full, they should be combined into one. Lake Mead would be deeper, and its evaporative losses would increase. But the surface area of Lake Powell would be dramatically reduced, and the evaporated water from there would be saved. Furthermore, moving the water out of Glen Canyon would move it from a valley that leaks like a sieve, into one that is watertight. The ongoing losses in Mead — according to proponents of the plan — would be more than offset by the immense savings at Lake Powell.

In all, according to Tom Myers, a hydrologist who was commissioned to research the implications of the plan for the Glen Canyon Institute, an environmental group advocating for combining the two reservoirs, about 179 billion gallons of water would be saved each year — more than enough to supply the population of the city of Los Angeles.

The argument has logical weight because both reservoirs have been struggling to remain half full, and may not ever refill. Researchers at the Scripps Institution of Oceanography at the University of California San Diego gave Lake Mead a 50 percent chance of running dry by 2021. The federal Bureau of Reclamation itself forecasts that the amount of water runoff will decrease another 9 percent by 2050 in the Colorado River basin, as temperatures increase. And last year a group of academic researchers declared that the Colorado River basin — already in its 16th year of drought, may be headed toward the worst water crisis in 1,000 years.

Meanwhile the Bureau predicts that demand will continue to increase on the river so much that by 2060 the region will run short by a trillion gallons each year.

“They all show a huge deficit and they all show the reservoirs will likely never fill again,” said Eric Balken, executive director of the Glen Canyon Institute. “So let’s rethink the game plan here.”

According to the proposal the Glen Canyon Dam itself would not be removed. Rather, its gates would be opened, and the water behind it allowed to pass through, restoring the natural flows through into the Grand Canyon just below it, draining the Lake Powell reservoir, and allowing the legendarily scenic landscape of Glen Canyon to be resurrected.

The water would not be lost. It would simply flow down through the Grand Canyon and be recaptured behind the Hoover Dam in Lake Mead.

“To me it is a no brainer,” said David Wegner, who studied Glen Canyon as a scientist with the Department of Interior for more than 20 years, and later advised the U.S. House of Representatives Committee on Natural Resources on management of Western water issues. “You’ve got very few options.”

According to Balken, the process could unfold in stages, and it wouldn’t take much. For a while, the water from the lake would simply drain through the dam, as if the plug were pulled from a giant bathtub. The lake levels — already nearly 100 feet below their peak now — would be allowed to drop another 100 feet, until they reach the intakes for the dam’s generators. One option would be to maintain the lake levels there, allowing minimal power production. Just that incremental shift would allow vast tracts of land now submerged to be restored.

A second stage of drawdown could lower the levels further, to a set of release pipes about 200 feet above the foot of the dam. The dam’s power plant would be shut down, saving tens of millions of dollars in operating costs. It would also dramatically alter water flows through the Grand Canyon, and would have to be carefully coordinated with water levels in Lake Mead, downriver. For the Colorado to be truly restored to its natural riverbed, a third stage, in which bypass tunnels would have to be drilled to allow the water to circumvent the concrete footing of the dam, would have to be pursued.

But proponents of the plan — which they call “fill Mead first” — say the lake may not need to be completely drained. Every vertical foot the waters drop reveals whole stretches of long-drowned desert wilderness. Much of the Glen Canyon valley has already been resurrected, as the lake levels have receded, and several of Powell’s recreational boat launches now hang above the shoreline, dry.

As the waters fall further, broad swaths of river pinned between vertical canyon walls would be transformed into remote wilderness valleys, their floors once again inviting to explore on horseback or on foot. Dozens of archeological sites, their walls covered in petroglyphs, would be revealed. For a while parts of these lands would be covered in a heavy silt, the result of decades of fine mud settling at the bottom of the lake. But vegetation would quickly root in the fertile soils, and heavy storms would flush the mud out the bottom of the canyon, scouring the sandstone clean. Eventually, perhaps after a few decades, even the white watermarks painted across the sides of the valley — telltale signs of the manmade flood — would begin to disappear.

As the silt gets washed downstream, a cloudy stew would course through the Grand Canyon, temporarily disrupting the gentle ecology of that part of the river. But that silt has been sorely missed, and it would soon settle, restoring beaches long ago deprived of sediment. The flow of the river through the Grand Canyon would once again be defined mainly by the amount of precipitation gathered by the mountains upstream. Four native endangered species of fish would presumably thrive in their restored waters.

Restoring the land of Glen Canyon this way has long been the campaign of ardent environmentalists. Brower — who mounted an intense effort to save Glen Canyon almost as soon as he’d agreed to allow it to be drowned — called the reservoir his greatest regret, and the Glen Canyon Dam has been a potent symbol of the desecration of wild places ever since. Now the shortages on the river, and the promise that climate change are certain to make them worse, have breathed new, pragmatic life into their arguments.

Whether the “Fill Mead First” argument pencils out for its benefit to the water supply depends on whether Myers’ assumptions about the amount of water that leaks out of the bottom of Lake Powell are accurate. The U.S. Bureau of Reclamation has long said that water that seeps into the ground eventually returns to the river. Myers studied the fault patterns in the rock bed, and the direction of groundwater flow, and concluded that much of the water seeps away never to come back — an amount that adds up to about 124 billion gallons each year. His research was published in the Journal of The American Water Resources Association in 2013.

Still, the river’s water managers believe his models are flawed. “We don’t agree with the fundamental assumptions that this water is being lost permanently,” said Colby Pellegrino, the Colorado River Programs Manager for the Southern Nevada Water Authority. Pellegrino’s office ran its own numbers to see if combining the reservoirs would save water, and said the math worked out as a wash.

“This is an attempt to find a water supply rationale which supports their recreational focus and narrow view of what the river should look like,” she said.

From a viewpoint above Glen Canyon Dam, a placid lake stretches in one direction, and a tangle of electrical wires in the other. The dam’s power station is a nest of infrastructure locked behind a razor wire fence at the top of a vertiginous cliff, and it’s capable of sending 1,320 megawatts of electric power shooting out across the moon-like landscape of southern Utah, toward millions of homes.

Glen Canyon Dam’s staunchest defenders say its power output is clean, affordable, and vital. Moreover, they say those who think climate change has doomed the traditional ways of managing the Colorado’s water underestimate the political complexities of doing away with the power dams generate.

“The questions that are being asked are very legitimate questions,” Connor says. “But you’ve got to have some political support… and that just doesn’t exist.”

The government relies on Glen Canyon Dam to produce power — and not only to produce it, but to sell it, in order to repay the U.S. Treasury for a big chunk of the cost of Glen Canyon’s construction and infrastructure upgrades, and to fund water conservation initiatives across Western states.

From the start, Glen Canyon was conceived as a giant hydroelectric generating plant, one so large its planners boasted that the sale of its power would not only pay for the dam’s construction, but finance smaller dams across the West. Today Glen Canyon is the largest facility run by the Western Area Power Administration, the federal energy agency that sells wholesale, federally generated hydropower onto the Western electrical grid.

The dam’s power reaches 3.2 million customers from California to New Mexico, according to a recent analysis commissioned by the Glen Canyon Institute. And while much of the power is resold at retail rates, its greatest dependents are Native American tribes and the U.S. Department of Defense — which are accustomed to getting their power wholesale, at a government-subsidized price that Glen Canyon Institute’s consultants calculated was a little more than one third market rates.

Were Glen Canyon to stop operating, its defenders say, those who rely on its power would face astronomical price hikes — or perhaps lose their access to electrical entirely.

That may eventually happen, however, whether the river’s managers agree to dismantle Glen Canyon or not.

The lower the lake level drops, the less power the dam can generate, and the less power WAPA has to sell. Researchers in the northern Colorado River basin states have even begun considering when Lake Powell’s lake levels might reach “dead pool,” or the level at which the turbines can no longer produce any power at all.

Already, the lake’s levels have dropped more than 90 feet since 1999. If they drop another 100 feet or so, the dam’s turbines begin sucking air. Glen Canyon has been generating at roughly 43 percent of its capacity. Some experts predict in the future that nest of wires will convey, on average, about 600 megawatts of power.

That has left WAPA — and the Department of Interior — in a bind. The agency has long-term contracts to deliver power, and it can’t simply come up short. When there’s not enough water WAPA has to purchase the power it can’t make itself in order to meet its obligations. WAPA spent $62 million on extra power to fulfill its contracts in its fiscal 2014, and, after managing its water to bring the water levels in Lake Powell back up, $22 million for its 2015 operations, the vast majority of which was to make up for shortfalls at Glen Canyon.

The shortfalls — like falling dominoes — could eventually leave the region’s broader dam and water infrastructure system in the lurch, as smaller dams and reservoirs that rely on money from Glen Canyon’s power sales may have to do without.

For example the Dolores Water Conservancy District, a small utility in southern Colorado which operates the McPhee Dam, recently used $7 million in power-revenues from the Colorado River Storage Project to pay for pump upgrades at its facilities. If Glen Canyon Dam wasn’t generating power, that upgrade might never have happened. “Without the basin power funds the viability of our project becomes a lot more challenging,” says the district’s general manager, Mike Preston. “I don’t know how we would do it frankly.”

Meanwhile nature is weaning the West off its power subsidies all on its own. As WAPA’s costs increase, the economic benefit of the dam has already decreased. If production drops further, the conservation programs paid for by the dam’s slush fund will go unfunded.

Power consultants hired by the Glen Canyon Institute to analyze the impact of shutting down the dam found that western power consumers have already reduced their reliance on Glen Canyon power, and that power constitutes less than one percent of western supply. There are end users that rely on Glen Canyon for all of their power — the Navajo Tribe, and the U.S. Department of Energy’s labs in Albuquerque, New Mexico — and these few groups would expect large cost increases as their subsidies disappear. But the vast majority of residential consumers would see their bills jump nominally, by just eight cents per month, should Glen Canyon shut down.

Still — as the Glen Canyon Institute report points out — if Lake Mead and Lake Powell were combined, that worst-case blow would likely be blunted. With the added mass of water behind the Hoover Dam — another federal hydropower facility — generators there would produce more power than they do now, and that surplus, according to the Glen Canyon Institute, could replace about 17 percent of what Glen Canyon produces today.

The amount of water in Lake Powell, of course, depends on the amount of water that flows into it. But even as the region scrambles to save its reservoir — and its river — projects are being planned which would take large additional amounts of water out of the Colorado before it can even fill Powell or fuel the Glen Canyon Dam.

Colorado is planning to build a new reservoir at a place called Windy Gap, and to more than triple the capacity of its Gross Reservoir by raising the height of the dam there. Wyoming is considering an expansion of its Fontenelle Dam on the Green River. Utah just filed an application to build a 140-mile pipeline to divert water out of Lake Powell. The planned new projects would divert another 83 billion gallons of water away from Glen Canyon Dam each year

Downriver, New Mexico is preparing to spend close to one billion dollars to build a new dam and reservoir on the Gila River — a river mostly spoken for. The project promises to capture water only in years when there is so much extra that Arizona right-holders downstream can’t use it all, and to do so despite science which forecasts the Gila will have less and less water in the future. Furthermore, like Lake Powell, the reservoir site in New Mexico also promises to leak, so much so that builders now want to line the entire reservoir valley with rubber before it’s filled, an undertaking that will cost more than construction of the dam itself.

“Every supplier in the basin is trying to build anything they can to get as much water as they can,” said Gary Wockner, the executive director of the environmental organization Save the Colorado, “trying to get the last legally allowed drop that they can before the red flag goes up.”

That every drop of water on the Colorado counts is undisputed. Last month the lower basin states announced they were close to a historic, and difficult, agreement to voluntarily cede a small share of their water, just to keep the reservoirs functioning. An ambitious, multi-million effort to buy even small amounts of water off of Colorado farmers and send it to fill Lake Powell has, after two years, failed to garner more than a few million gallons. It appears that stakeholders are ready to do whatever it takes, including re-envisioning the use of dams.

“I think it’s questionable whether you can build a lot more reservoirs in hot, arid environments,” the Interior department’s Connor told ProPublica.

Still, the proposal to “Fill Mead First” appears to be a step too far.

Ultimately the decision to drain Lake Powell — or perhaps to forgo any of the other new dam and water projects now in the works on the river — comes down to a question of whether the seven states and Mexico that share the Colorado river really need the water badly enough.

When they do, abandoning parochial concerns about how the river is supposed to work, and changing the status quo, however uncomfortable or complicated, will begin to seem worth it.

“There’s just a lot that’s built on this scheme of management and the existence of Glen Canyon Dam,” said Jim Lochhead, the chief executive of Denver’s water utility and a former Colorado state negotiator on Colorado River matters. Lochhead says the change would likely require an act of Congress, plus an agreement between seven state legislatures and a revised treaty with Mexico, and a multi-year federal environmental impact analysis.

“A half a million acre feet sounds like a lot of water,” he said, referring to the amount that would be saved by combining the Powell and Mead reservoirs, “but I don’t think it’s significant enough, frankly, to justify going through all of that.”

Correction, May 20, 2016: An earlier version of this article misspelled the surname of the Deputy Secretary of the Interior. He is Michael Connor, not Conner.

ProPublica is a Pulitzer Prize-winning investigative newsroom.