The U.S. Bureau of Reclamation on July 16 decreased slightly the water supply outlook for Yakima River basin irrigators with junior water rights, as Central Washington works through its worst water shortage in nine years.

The bureau forecast irrigators will receive 50% of their full allotments this year, slightly less than the 51% projected in early July. The outlook is still better than the 47% allotment the bureau projected in early June.

Rain in June improved the outlook. Triple-digit heat in July contributed to the slight drop in the past two weeks, said Chris Lynch, reclamation bureau river operations engineer.

“We had a really wet June,” he said. “The past two weeks have been almost the opposite.”

The bureau manages a system that irrigates more than 400,000 acres in Central Washington. Senior water right holders will receive full allotments. Rationing for junior water right holders began May 21.

The bureau will update the outlook Aug. 1. If the region has above-average rain, the season’s supply could rise to 58%, the bureau projects. On the other hand, the supply could possibly drop to as low as 45%.

The water supply is the lowest since 2015. The Washington State Department of Agriculture estimated drought losses that year at $75.78 million in the 72,000-acre Roza Irrigation District based in Sunnyside.

Drought losses are unlikely to be as high this year because there was an oversupply of crops such as apples, hops and wine grapes heading into the season, district manager Scott Revell said.

“In our district, there is a lot of market-related fallowing that has happened,” he said. “I wouldn’t be surprised if it’s at least double the average.”

The irrigation season will end early, though the district expects to supply water for the first few days of October, Revell said. The district normally delivers water until mid-October.

Reclamation’s five Central Washington reservoirs are low, holding only 70% of their normal volume of water for this time of year. Rainfall at the reservoirs has been below normal for most months this year.

Daytime temperatures in July have been consistently over 100. The airport in Yakima hit 106 degrees on July 9, according to the National Weather Service.

The weather service warned Monday that a heat wave will hit much of the West, including Eastern Washington, beginning July 23.

Wine grape grower Jim Willard said he plans every year on a week of 100-plus degree days.

“You’re just going to see that,” he said. “I don’t view it really as out of the normal.”

The region’s farm income will be down this year, Willard predicted.

“The big factor here is the economy, and the drought isn’t helping anything,” he said.