Courtesy of U.S. Bureau of Reclamation
YAKIMA, Wash. — The first winter storm should start turning the corner on water storage in five mountain reservoirs serving the Yakima Basin that are at their lowest levels in years.
Several inches of rain, and snow above 7,000 feet, was forecast for the Cascade Mountains at the end of October and the first few days of November.
“If this rain comes it should start the rebound to keep going through winter in the reservoirs,” said Chris Lynch, hydrologist for the U.S. Bureau of Reclamation’s Yakima Project in Yakima.
The bureau manages water storage and flow through reservoirs, streams and rivers to provide irrigation water to 464,000 acres of mostly farmland along 175 miles of the 214-mile-long Yakima River in the Kittitas and Yakima valleys.
At full capacity, the five reservoirs store a little more than 1 million acre feet of water. Irrigators normally need another 700,000 acre feet and usually 2.3 million acre feet is stored in mountain snowpack, according to the state Department of Ecology. But snowpack was far less this year because of drought and use of reservoir water, while rationed to junior water right holders, began earlier than normal.
As a result, the five reservoirs hit a season-ending low of 107,323 acre feet of water on Oct. 27, compared 330,000 last year and a 30-year average of 270,000.
Lynch and his colleagues at the bureau had hoped to maintain 135,000, but he said 107,323 “wasn’t too bad for a drought year.”
The low was 106,487 in the last drought year in 2005 and the record low was 51,680 in 1973, he said.
The irrigation season ended on schedule on Oct. 20, with Sunnyside Irrigation District being the last to shut down. Usually, the reservoirs turn the corner before then from rain. This October has been drier than normal, Lynch said.
The most visible of the five reservoirs is Keechelus Lake along Interstate 90, east of Snoqualmie Pass.
“People say they’ve never seen it this low, but they have. It’s just been a while,” Lynch said.
Nearby Kachess and Cle Elum lakes, not visible from the freeway, also are very low. So are the other two reservoirs, Rimrock and Bumping lakes near White Pass. All together, the five are at about 10 percent of storage capacity.
Given how low they are and forecasts for another mild, dry winter, Lynch is concerned about the reservoirs and snowpack.
“I’ve heard from different meteorologists that the fall may be reasonably wet, but maybe not snow, and the winter from the first of the year on will be drier than average,” he said.
El Nino years can be below average to near average precipitation, he said.
“When we’re drained this far down it is a concern. It’s harder to fill them. It makes us more nervous. We need the right balance between reservoir storage and snowpack,” he said. “Last year, we got the reservoirs filled but didn’t have much snowpack after April 1.”