Yakima Valley junior water rights holders looking at reduced supply for coming year

Junior water rights holders in the Yakima River basin will not be getting a full share of water this year, based on early forecasts.

U.S. Bureau of Reclamation officials, using a “moderate” estimate of precipitation and water runoff for the coming year, said during a Monday meeting that the junior rights holders should expect 72% of their water allotments for the year.

The five reservoirs in the Yakima River Basin system — Kachess Lake, Keechelus Lake, Cle Elum Lake, Bumping Lake and Rimrock Lake — are at a combined 39% of full capacity, which is about 64.8% average for the period from 1991-2020, said Doug Call, the BOR’s river operator.

The precipitation — rain and snow — totaled 143.83 inches from Oct. 1 to March 3, which is about 88% of average, Call said.

“It looks fairly promising we could accumulate more precipitation,” Call said.

Using a “moderate” calculation for rain, runoff and water use in the coming year, the BOR anticipates that the junior water rights holders would receive 72% of their allotted water rights, but hydrologist Chris Lynch said the number could change based on conditions.

Water rights are essentially divided into senior rights, those acquired before 1905, and those acquired after those dates are considered junior rights. Junior rights to water can be reduced or even cut off during droughts to ensure the senior rights holders receive their full allocation.

Lynch said last year’s forecast called for an 86% pro-rationing, but by the end of the year it ended up at 72%.

Lynch said February’s precipitation went up from 30 to 70% of average last week, and he’s hoping that March will have similar bursts of precipitation.

Looking at the forecasts and estimates, Lynch said there was a “decent” chance that Cle Elum and Rimrock lakes could reach full capacity before BOR needs to draw on them, while Bumping Lake is expected to fill. Keechelus and Kachess will likely not reach full capacity before their water is needed, Lynch said.