Amid the wave of dams coming down across the nation, several places are bucking the trend. New dams have been proposed in California, Colorado, Utah and other Western states. The motivations behind the projects are complex, but in some cases the same fears drive dam defenders and detractors alike: a drier future and rising populations.

Utah is seeking additional water sources to address its growth. There, legislators decreed in 1991 that the Bear River, the Great Salt Lake’s largest tributary, should host a water development project. Two and a half decades later, scientists, policy experts, environmentalists, residents and water managers are still grappling with whether or not — and how — to move forward with damming the Bear.

The answers they come to will have consequences for the $1.3 billion generated each year by industries reliant on the Great Salt Lake. The lake’s ecology, its wetlands and the millions of migratory birds that depend on it are also at risk — as is the health of the more than 2 million people who live nearby and could breathe in harmful dust from a drying lakebed. Caught between the dire costs of construction and the specter of dwindling water supplies, the Bear River diversion forces uncomfortable questions. Does it make sense to build a new dam project, decades after the heyday of big dams is over? How do you decide?

The Bear River wends 500 miles through Utah, Wyoming and Idaho, fed by runoff from the Uinta Mountains. The three states share its water, storing and diverting it to supply homes, generate power and irrigate fields. What’s left drains into the Great Salt Lake, delivering about 60 percent of the freshwater that flows into the lake each year.

Utah doesn’t use its full allotment, so the state Division of Water Resources is studying how to divert some of that water for nearby communities. The agency is currently evaluating possible reservoir sites and other project details. The final plan will likely include one to four dams, as well as pipelines to divert enough water to supply about 440,000 households. Official 2014 cost estimates for the overall project range from $1.7 billion to $2 billion.

Why consider building it? Population growth, says Marisa Egbert, program manager of the Bear River Development Project at the Utah Division of Water Resources. More than 2 million people already live in the areas served by the county and the three water districts that would receive the water, and that population number is expected to rise. Critics of the proposal say future needs could be met by water conservation, but Egbert says that alone won’t be enough if the population keeps growing, which is why the division is looking for new water sources. “Preparation’s in the lifeblood here,” she says. “It’s important to know what’s going on and what to expect.”

But what to expect can be a moving target. When the Bear River Development Act was first passed, supporters said the state would need the water by 2015. As population and water-use projections shifted, the deadline slipped to 2040. In January, the Utah Department of Natural Resources announced that it could push the project off even further, thanks to conservation and slower-than-anticipated growth.

That delay reflects recent shifts in both public attitudes toward conservation and Utah’s water politics, says Daniel McCool, a retired professor of political science at the University of Utah. McCool was one of about 40 people — state and local water managers, environmentalists and academics — who contributed to Utah’s 50-year water plan, released in July. Four years ago, when the group first met, support for large projects like damming the Bear River and constructing a pipeline from Lake Powell was a foregone conclusion, McCool says. But that started to change as fiscal conservatives joined environmental groups in citing concerns over economics and air pollution.

Egbert’s own title recently changed from project manager to program manager. “If there is a project, it’ll be beyond my career,” she says with a rueful smile, “so I’m not really managing a project.” Even so, the division is planning ahead, evaluating options for preserving utility corridors ahead of housing developments. Space is limited along the narrow I-15 corridor that runs between the Great Salt Lake and the Wasatch Front, and new houses are popping up every year.

The division estimates that about 60 percent of the water drawn from the Bear River would eventually return to the lake as treated wastewater. But the loss of the other 40 percent would cause the lake to fall by 8.5 to 14 inches, exposing between 30 and 45 square miles of lakebed, according to a 2016 study. That’s on top of the 11-foot decline humans have caused — mostly thanks to agriculture — since the mid-1800s. The additional drop could hurt the industries that rely on the lake. It would also be an ecological disaster, especially for the birds that rely on its marshes as migratory rest stops. The flow of people who visit the lake now because of its water and the wildlife it attracts — birdwatchers, recreational rowers, duck hunters — might dry up, too.

That flow includes people like R. Jefre Hicks, who took me out on the lake on a cold day in early April. As the intermittent rain went from light drizzle to jacket-soaking, Hicks kept one gloved hand firmly on the steering lever of his airboat. He gazed out at a mix of water and low grass called Willard Spur, near the mouth of the Bear River. Hicks, who is 56, grew up exploring the sea of cattail islands that was the Great Salt Lake during the 1970s, hunting waterfowl with his father. As teenagers, Hicks and his buddies would bring their decoys, waders and guns to school, then hurry down to the marshes along the lake for an hour at lunchtime before heading back to class.

The diversion would destroy an ecosystem around which he’s arranged his life. “If you have a connection to the Great Salt Lake, or to wetlands, or to birds or bird hunting, then it’s a big deal,” he told me. “A really big deal.”

The mountains of the Wasatch Range rose in the distance, their snowy slopes disappearing into hazy clouds. The noise and motion of the airboat suddenly stirred up thousands of birds, avocets, stilts, gulls and other water birds that swooped and darted in every direction, a mad scramble of motion above the surface of the Great Salt Lake. To think that Willard Spur “could go the way of a dust bowl —” Hicks said, pausing. “It just hurts to see it.” 

Emily Benson is an editorial fellow at High Country News.