UPDATE: April 24, 2015
Cliff Mass, professor of atmospheric sciences at the University of Washington, says in his blog that it is too early to be predicting severe drought in Western Washington this summer because of possible late-spring rains:
“I believe the media and some local politicians have gotten a bit too worried about our ‘drought.’ We have NOT had a precipitation drought at all….we are in a snow drought due to warm temperatures. The situation is unique and I suspect we will weather this summer far better than expected.”
The word seems to be getting around about the record-low snowpack in the mountains, which could create a shortage of drinking water and even lead to problems for salmon swimming upstream. Read about Gov. Jay Inslee’s expanded drought emergency, issued today, as well as the last update from the U.S. Department of Agriculture.
Kitsap Peninsula and the islands of Puget Sound are in their own worlds, fairly insulated from what is happening in the higher elevations. In these lower elevations, the key to water supplies is rainfall, not snow, and the outlook for the year is normal so far.
As you can see from the charts on this page (click to enlarge), this year’s rainfall has been tracking closely the long-term average. If the rains are light and steady, much of the water will soak into the ground and recharge the aquifers where most area residents get their water. The aquifer levels tend to rise and fall over multiple years, depending on the rainfall.
Casad Dam on the Union River, which supplies a majority of Bremerton’s water, filled in January, well ahead of schedule, said Kathleen Cahall, water resources manager for the city. The dam is scheduled for a normal drawdown, and Kathleen said she does not expect any water shortage.
“We filled the reservoir fairly early this year,” she said. “We are looking pretty good for the summer.”
October, the first month of the water year, was unusually wet, Kathleen said. December precipitation also was high. The other months were fairly normal for precipitation.
Precipitation in the Puget Sound region is expected to be below average for June, July and August, according to models by the NOAA’s Climate Prediction Center. Interestingly, large portions of the Central and Southwest U.S., Alaska and Florida can expect above-average precipitation. See U.S. map.
Streams on the Kitsap Peninsula are fed by surface water flows and shallow aquifers. At the moment, most of the streamflows are near their historical average. That’s not the case for the larger rivers in the Northwest, which rush out of the mountains. Most are well below their normal flows, as shown by the map with the dots.
Low streamflows usually mean higher temperatures and stress for salmon. Low flows also can affect fish passage in some stretches of the rivers while also reducing spawning areas.
While things look fairly good on the Kitsap Peninsula now, things can change quickly. We have different vulnerabilities than elsewhere. Climate-change models predict that rains will grow more intense in the future without changing annual precipitation very much. That means more of the water will run off the land and less will soak in, potentially reducing aquifer levels over time. Managing those underground water supplies will become more and more critical.