Solar energy could help restore Walker Lake

The sun's energy would be tapped to power a new process with the potential to aid an ecologically ailing Walker Lake.

Researchers at the University of Nevada, Reno are developing a "solar pond" with a newly patented membrane distillation system that could be used to remove excessive levels of salt from Walker Lake and similarly troubled bodies of water.

"This is the only thing that's been proposed as far as cleaning up the lake as opposed to bringing more water to the lake," said Amy Childress, a professor of civil and environmental engineering at UNR.

The process developed by doctoral candidate Francisco Suarez and colleagues traps solar heat within a 400-gallon laboratory tank, with collected energy powering the distillation system that removes concentrated salts.

"We can create pure water from this system," said Suarez, 29. "You could take this system and drop it anywhere, and you could create fresh drinking water."

Scientists hope to build an open-water system, perhaps hundreds of acres in size, in a portion of Walker Lake to test its effectiveness on a much larger scale.

Water levels at Walker Lake have plunged about 145 feet since the early 1880s, largely because of upstream agricultural diversions. Dropping water levels have resulted in spiking levels of salts and impurities, places the lake's fish and other wildlife in peril.

Millions of dollars have been spent pursuing strategies to get more water flowing to the lake, including through the use of alternative crops.

The solar pond technology could offer an opportunity to clean the lake's waters, with Nevada's plentiful sunshine providing a ready energy source to do so, researchers said.

"This can operate 24 hours a day using the stored energy. Very little electricity would be used," Suarez said.

The process could generate three acre-feet of clean water a year for every surface acre of water treated, he said.

Scott Tyler, another UNR professor involved in the research, said the process could be applied to other lakes with declining water levels and impurity problems. They could include places such as California's Salton Sea, the Great Salt Lake and Asia's Aral Sea.
By Jeff DeLong • jdelong@rgj.com • January 18, 2010