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Study says water transfer deal is raising dust and draining the Salton Sea

The Salton Sea is a terminal saltwater lake. It’s a flooded basin with no natural outlet, similar to the Great Salt Lake or the Aral Sea. And the Salton Sea is shrinking.

One of the reasons for that is the Imperial Water Transfer deal that has brought hundreds of thousands of acre feet of water to San Diego over the last two decades. The deal, signed 21 years ago, meant the Imperial Valley began transferring excess water from the valley’s farm fields to San Diego’s water taps.

That meant a lot less farm runoff that had been sustaining the Salton Sea.


San Diego State University economics professor Ryan Abman said the biggest effects of that conservation plan were seen about eight years into the agreement.

“So really, after 2011, we see a noticeable increase in the rate of decline of the water level and that leads to an increase in the increased rate of playa exposure. So more of this dust-emitting surface is being exposed every single year,” Abman said.

The “playa” he talks about is the bare lakebed that’s left after the water recedes

Abman is co-author of a study that examined the dust pollution from the Salton Sea playas and who it affected. He said areas with high poverty rates were greatly impacted.

“What we found is that after 2011 the change in pollution has been much more dramatic for these historically disadvantaged communities than for the nondisadvantaged communities,” he said.


The findings are borne out by data collected by the California Environmental Protection Agency (CalEPA). Their maps show census tracts in the Imperial Valley that are burdened by air pollution are typically the same ones that are home to disadvantaged communities.

Dust. It’s hazardous to your health

Dust pollution can cause asthma. Windstorms stir up dust and sand that cause inflammation and asthma in local residents who breathe it in, especially those who work outside.

Yeah. It can get really bad,” said Stewart Fleischman, a doctor with Coachella Valley Volunteers in Medicine, a free clinic in Indio. “You’re sitting in a chair and you’re wheezing, you can’t catch your breath and you have to use medicines to open the airways. Because of the chronic inflammation inside you’re also very subject to infections.”

If the dust is affecting disadvantaged communities near the Salton Sea that’s no surprise to some.

“I think the entire region can be characterized as low income or disadvantaged communities. The area where I live, all but one of the towns is classified, according to the California criteria, as disadvantaged communities,” said Tina Shields, the water manager at the Imperial Irrigation District (IID).

IID and the state of California are trying to reduce dust pollution and ensure that some of that Colorado River water runs to the Salton Sea.

Furrows cut into the exposed lakebed at the Salton Sea help cut down on wind on Feb. 25, 2019.
Kris Arciaga
Furrows cut into the exposed lakebed at the Salton Sea help cut down on wind on Feb. 25, 2019.

Dust mitigation projects include planting rows of salt-tolerant plants to catch the particulates. Also, plowing furrows to roughen the soil and make it less flat.

“You have to put the right project on the right soil though. Surface roughening is not appropriate for sand because you’re just stirring the pot,” Shields said.

“But if you have land, such as in the southern region, where you have the clay soil and you do the surface roughening, we've found it to be upward of 99% effective for controlling those emissions.”

The future of the Salton Sea

Some people have called the Salton Sea a mistake, caused by a dike rupture in 1905. But back in the days when the Colorado River ran wild it would change course with floods and fill up that basin quite often.

It sometimes covered a space from what’s now Palm Springs all the way to Mexicali. Geologist Tom Rockwell is a professor emeritus from SDSU, and he’s studied evidence of water levels in the Salton Sea basin over the past 5,000 years.

Based on his research, the lake may have shrunk to the size of a puddle from time to time, but there’s almost always been a Salton Sea, fed by the Colorado River.

“For instance, in the last 1,000 or 1,100 years, it’s flipped course and drained into the Salton Trough six times, the last one being around 1730 C.E. And when it does, it fills up to around 13 meters elevation, and then drains back to the Gulf (of California),” Rockwell said.

Today’s Salton Sea remains a habitat for fish and migratory birds, and the best way to contain windswept dust. Tina Shields had this to say when asked if she thinks it will dry up.

“Not if we can help it," she said. "The goal of the Imperial Irrigation District is to continue to have water resources for our community and our agricultural water users. And as long as you have agriculture, you will have runoff.”

That runoff is still the greatest source of water for the Salton Sea.

The way things are going IID estimates the Salton Sea will stabilize in 2047.

It will be two-thirds its current size and it’ll have an estimated 130 square miles of exposed lakebed, compared to the water levels in 2002. That was the year before the start of the Imperial Water Transfer deal.