Washington Water Supply

Last revised: March 14, 2017

Watching the water supply

If you’re ready for spring, the ongoing rain and snow may be getting old. But it’s great for our state’s water supply, if that’s any consolation. We’re building up our mountain snowpack and seeing strong rivers and streams. Overall, we’re in good shape.

Let’s take a look at what’s going on as of March 14:

Status of supplies

Weather and outlook | January was chilly – the coldest since 1993. Temperatures were between 6 and 8 degrees below normal in some areas. February was also cooler than normal and really wet – Washington soaked up between 200 to 400 percent of our normal precipitation last month.

The outlook for the remainder of March indicates there is still more snow and precipitation to come. With spring heading our way, we can expect warmer days and freezing levels to move to higher elevations. NOAA’s experimental three- to four-week outlook is suggesting a higher chance of warmer-than-average conditions by the beginning of April. But there’s no reason to think we’ll experience an early heat wave that could imperil our snowpack (like what happened last year).

Snowpack | Our current statewide snowpack is 120 percent of normal. This time last year, we were at 108 percent. In 2015, when we experienced the worst drought on record, we were at 25 percent of normal.

The cold and dry weather in January had been digging us into a snowpack hole but February and March have delivered. We’ve had a lot of snow, especially in the Cascades and Olympics. Some locations in the central Cascades received upwards of 42 inches during a single storm! Many basins in the state have reached their annual peak snowpack several weeks earlier than usual.

For you snow geeks, check out this plot of snow water equivalent for the Walla Walla/Touchet basins, that black line is this year:

NRCS SWE Plots Water Year 2017 for Walla Walla and Touchet Basins

River and streams | Rivers and streams across the state are running at normal or above-normal levels. Only three percent of them are below normal. The forecasted snowpack runoff for April through September is very favorable across the state. On average, our rivers are expected to run just slightly less to slightly greater than normal, so kayakers should be able to enjoy an excellent season of whitewater. The forecasts look especially promising for the Walla Walla and Lower Snake River watersheds, compared to recent summers.

Agriculture | The U.S. Bureau of Reclamation manages five large reservoirs in the Yakima River basin, a major agricultural center for our state. On March 6, they released their summer water supply forecast for irrigators who depend on those reservoirs. It looks to be positive news – the bureau is anticipating a full water supply for senior water users and 96 percent for junior users.

Drinking water | Water suppliers for our biggest cities are in good shape, especially with the recent rain and snow.

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Water Supply Information




NRCS Current Snow Water Equivalent (SWE) % of Normal

2016 Spring Update: Groundwater Level/Storage Response in Washington State