SPOKANE — Warming temperatures in the future will produce changes in the Columbia River Basin, with more precipitation in winter months and less during the summer, according to a new study released Tuesday by the U.S. Bureau of Reclamation.
The assessment projected impacts on water resources in the states of Idaho, Nevada, Montana, Oregon and Washington over the next seven decades.
It found that warming temperatures will continue across the basin. While there will not be significant changes in the mean annual precipitation, its timing will change significantly, the assessment found.
The assessment “will give water managers new information to plan for sustainable water supplies now and into the future,” Reclamation Commissioner Estevan L?pez said.
“This serves to establish a foundation for in-depth studies that will include more detailed climate adaptation strategies,” he added.
The assessment used five possible climate scenarios to simulate temperature, precipitation and runoff. They were separated into four future periods, the 2020s, 2040s, 2060s and 2080s.
Future climate data was calculated at 157 locations across the vast Columbia River Basin in the Pacific Northwest.
With the warming temperatures and increased precipitation in the winter, runoff was generally expected to increase in the winter and decline in the summer, the assessment found.
Three areas were specifically studied, the Columbia River above The Dalles, Snake River at Brownlee Dam and the Yakima River at Parker. At these three points, the mean snow water equivalent is projected to decline at all locations. The assessment projected a trend that indicated there would be an increase in runoff from December to March and a decrease in runoff from April to July.
This assessment was released in conjunction with the first White House Summit on Water in observance of World Water Day.
During the White House summit, the Obama administration announced new commitments to enhance the sustainability of water in the United States.
Two of those sustainability projects are in the Yakima and Methow river basins, and are led by the Washington state Department of Ecology.
“In Washington state, we recognize the importance of long-term water security to both our environment and our economy,” said Gov. Jay Inslee. “These projects in Yakima and the Methow Valley represent the crucial balance of needs by protecting natural habitats and wildlife, while supporting family farms, businesses and residents.”
The Yakima Basin Integrated Plan is considered a case study for finding creative water solutions that support better management of water for both economic purposes and environmental benefits.
The Methow Instream Flow Improvement Project is highlighted as a program that invests in updating aging water infrastructure, improves stream flows for imperiled salmon and steelhead, and provides the Town of Twisp and irrigators with a more reliable water supply.