Water supply update: Yakima Basin

Lack of spring rain puts irrigators on storage, other users shut off 

What a difference one month can make.
Last time we blogged about the statewide water picture in February, we discussed Winter Storm Oliver’s benefits to the Cascade snowpack. That storm dumped enough snow to close mountain passes and eased tensions we expressed in our Jan. 19, 2018 blog post, when we reported about unseasonably warm temperatures for November and December 2017.
Then there was May — when a warm and dry streak produced ultra-high snowpack runoff. Much of Western Washington and the Yakima River Basin are abnormally dry, as can be seen in this United States Drought monitor map of Washington. Already, water uses have been curtailed in the Chehalis River Basin.
Picture of Cle Elum dam, water on the left.

Cle Elum dam provides stored water for irrigators in the Yakima River Basin

In April, water managers announced a 100 percent water supply for Yakima irrigators this season. They optimistically predicted all water users were set.

That changed on June 11, when the U.S. Bureau of Reclamation began to rely on stored water at its five Cascade reservoirs.

They also announced that junior irrigation districts like  Roza and Kittitas Reclamation and others will receive at best 96 percent of their water allocation — an amount that could worsen as the season progresses.
Because of this forecast, 300 more-junior water right holders along the Yakima River and its many tributaries are now shut off by court order. These users — with priority dates after May 10, 1905, as a group — are part of an adjudicated water basin that controls when surface water may be diverted.

What happened?

While reservoirs have been filling because of good snowfall, snowpack alone can’t maintain an adequate water supply. Spring rains are needed to supplement supplies.

Since February, we’ve seen only modest precipitation in the Yakima Valley. The unseasonably warm, dry — and in some areas, record-breaking May — shows how a single month can turn things askew.

A bit of history, a bit of context for the Yakima

Back in 2005, Yakima County Superior Court entered a permanent order that directs how post-1905 water rights are regulated under the Yakima River Basin adjudication, known as Ecology v Acquavella. Why is May 10, 1905, a key date? That’s the date the federal government claimed all remaining surface water in the watershed for Reclamation's Yakima Irrigation Project.
Settlers whose water rights predate this date are called senior. They receive 100 percent of their allocation every year. Users whose water rights began after this date are called junior.
Water users under the May 10, 1905 water right — including the Roza Irrigation and Kittitas Reclamation districts — will receive a pro-rated, reduced amount of water for the season, commonly called pro-rationing.
When water is pro-rated for May 10, 1905 rights, other junior users are shut off entirely.
The Yakama Nation has ancestral water rights, which protect instream flows for fish, and the federal government also has obligations to meet streamflows for fish in the watershed. These water needs are also taken into account for the total water supply.

Formal curtailment notices

Today’s curtailment orders have been sent by mail. Camp and cabin owners who participated in our mitigation program will not be curtailed. The 300 water right holders being curtailed have the ability to lease water from other irrigators or water right holders within the Yakima Basin if they are able.

This is the first time we have sent formal orders curtailing post-1905 surface water use. In 2015, a severe drought year, post-1905 curtailments were posted in the Yakima River Basin Water Rights Adjudication Notice, an informal newsletter sent to water-right holders. That year, senior water users along many tributaries also were shut off or negotiated to use shared water from their neighbors.

Water users with questions may call our Central Regional office water rights customer service line at 509-575-2597.

What's ahead for Washington?

We were hopeful a normal spring, with rain and cool temperatures, would mean there’d be plenty of water across the state.

Increasingly, we’re seeing a pattern where water managers need to stretch supplies to meet October needs. Oliver’s mid-February blast helped us, but warm temperatures in May caused mountain snowpack across the state to diminish more swiftly. 

It looks like this could put us in a difficult spot later in the summer, making water scarce for irrigation and fish.
And, indeed, the Climate Prediction Center and other forecasting agencies have forecast a warmer- and drier-than-normal summer.
On June 29, we are convening our expert partners on the Water Supply Availability Committee to appraise the most current streamflow and reservoir conditions. We’ll also update our statewide water conditions webpage with new information where you can keep tabs.
We’re anticipating needs and will be responsive should water shortages prevail. So stay tuned.
Drought map of Washington from June 12, 2018