Runoff filling dry lake, covering Saltese Flats

Spokane County officials can take no credit for the lake that has risen on Saltese Flats south of Spokane Valley.

The county’s ratepayer-funded Utilities Division has purchased about 500 acres of Saltese Flats for future disposal of treated wastewater, but the water that has pooled there this spring is all natural.

“We’re having a huge runoff this year, compared with what is typical,” Utilities Director Bruce Rawls said.

Except during periods of heavy runoff, the area has been mostly a dry lakebed since Saltese Lake was drained about 110 years ago for agriculture.

Highly treated effluent from the county’s new sewage treatment plant, to be completed late this year, could restore the lake if it becomes impractical to discharge wastewater into the Spokane River.

County officials expect the treatment plant to receive a river discharge permit from the state Department of Ecology later this month.

Rawls said the county is about to design a Phase I Saltese project that would create a more dependable lake and wetland, using natural runoff. However, the work isn’t scheduled to begin until the summer of 2013.

“We’re looking at making a 40-acre impoundment of the natural water, about three to four feet deep,” Rawls said.

Water from the pond would be channeled toward Shelley Lake in Spokane Valley in a way that would create wetlands on the county land but not a stream.

Eventually, Rawls said, some water might be sent down an old canal to Shelley Lake, which often goes dry to the chagrin of surrounding homeowners. But nothing has been planned so far.

Part of the Phase I planning will include a 100-year flood analysis to make sure the project doesn’t worsen the natural flooding that already is expected at least once in a century.

Rawls said the final project will be designed to handle 2 million gallons a day of wastewater – enough to accommodate the county treatment plant and about 800,000 gallons a day from the Liberty Lake Sewer and Water District.

He said district officials are interested in switching from river to land disposal of their wastewater. If that happens, it probably would be five or six years from now, Rawls said.

The sewer district would share in the construction and operating costs if it decides to team up with the county.

Meanwhile, Rawls said, the preliminary and later phases of the project will provide a public amenity. There will be open space, bird habitat and trails, he said.

A trail eventually might lead from Saltese Flats, across newly acquired Spokane County Conservation Futures Land, to an existing trail system at Liberty Lake, Rawls said.