The Dalles Dam

The Dalles Dam on the Columbia River. The water supply for the river system will be ample, experts say.

COLUMBIA LAKE, B.C. — Drought plagues much of the West, but officials predict abundant water supplies this year for Pacific Northwest irrigators who rely on the Columbia River System.

That’s good news for thousands of U.S. farms that rely on drainage from the Columbia River watershed, spanning Oregon, Washington, Idaho, western Montana and small portions of Wyoming, Utah and Nevada.

The Columbia — the Pacific Northwest’s largest river — begins in the Rocky Mountains of British Columbia, Canada, zigzags into Washington state, turns west into Oregon and finally empties into the Pacific Ocean. The river’s largest tributary is the Snake River, which crosses Idaho.

The recent positive forecast comes after a winter of heavy snowpack in British Columbia.

The Canadian Drought Monitor’s most recent report labels the region surrounding the river’s headwaters as “abnormally dry” this spring due to meager rainfall — 40% below average. But because of a snowy winter, officials say water supplies look healthy.

“I don’t think (irrigators) will have any problems with water supplies on the Columbia this year,” said Nick Bond, Washington state climatologist. “It’s tapping that healthy snowpack. The places that are kind of under the gun are the lower elevations where they’ve had an extended period of subpar precipitation and so forth.”

Bond said farmers that rely on the Columbia are much more fortunate than irrigators in other regions, such as farmers in the Klamath Basin straddling the Oregon-California border.

According to an April 1 snowpack report from British Columbia’s River Forecast Centre, snowpack in the Upper Columbia River Basin is 108% of normal for this time of year.

The water level at The Dalles Dam in Oregon also looks good, according to Joye Redfield-Wilder, Washington State Department of Ecology public information officer. That’s an important indicator for water allocations.

According to rules adopted in 1980, if the dam’s April-September water flow falls below 60 million acre-feet, junior water right users could lose allocations. Data from the Northwest River Forecast Center April 26 show the projected water flow for the dam April through September 2021 is well above that threshold, at 81 million acre-feet, with only a 1 in 10 chance of falling below 76 million acre-feet.

“It’s looking good,” said Redfield-Wilder.

The Columbia River Basin includes 15.4 million acres of farmland across Oregon and Washington alone, according to the 2017 USDA Census of Agriculture. The highest-producing farmland in that region — nearly 1.7 million acres — is irrigated.

Washington state farmers especially rely on water from the Columbia Basin Project, managed by the U.S. Bureau of Reclamation, which serves 720,000 acres of farmland, including potatoes, sweet corn, onions, grapes, hops, fruit trees and alfalfa.

Bond, the climatologist, said while it might seem strange that the Columbia River is getting more water while other areas are getting less, it makes sense according to current climate change models, which predict lower latitudes will experience increasing drought while higher latitudes will experience more extreme winter snowfalls.

He expects this trend to continue.

“If anything, while other places are getting drier, the Columbia River overall may be getting more water in the future than in historical times,” he said.

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