Climate Change and the Columbia River Basin


Climate change is becoming an increasingly important component of water demand and supply forecasting. A number of scientific assessments have concluded that the Earth’s average temperature will increase during the twenty-first century ( Climate models used in these assessments predict that both temperature and precipitation will significantly increase in the Pacific Northwest over the next 50 years.
The potential consequences to water resources in the Pacific Northwest associated with warmer temperatures, greater precipitation, and a shift in winter precipitation type from snow to rain include (Hamlet et al., 2001):
  • Reduced snow packs
  • Higher winter streamflows
  • Increased flood potential
  • Earlier snowmelt-generated peak flows
  • Lower summer flows.


What is Ecology doing to address Climate Change in the Columbia River Basin?

Ecology is participating with other state and federal agencies to fund a study by the Climate Impacts Group that will provide greater accuracy in predicting climate change in the Columbia River Basin - with a particular focus on the Yakima, Walla Walla, Wenatchee, and Okanogan watersheds. The study is expected to be completed in 2010.

What are the effects of Climate Change on the Columbia River?

In addition to changing supply, climate change has the potential to change existing crop demands. For example, in Eastern Washington (within the greater Columbia River Basin), US Geological Survey reports approximately 1.7 million acres of irrigated crops in the greater Columbia Basin. If 20 years from now climate change has resulted in a need for an added inch of water per acre, due to hotter weather and decreasing summer rain, then 140,000 acre-feet more water will be needed to maintain current crop production. There is also 5.3 million acres of non-irrigated agriculture in the basin (e.g. dry-land wheat). Increasing temperatures and shifting of water availability due to climate change may result in some of these lands moving to irrigation to maintain yield and profitability, or a decrease in yield for those that cannot obtain irrigation water. This issue will be included in the next Ecology agricultural demand study in 2009.


 View a PowerPoint presentation about
"Climate Change and Water in the Columbia River Basin" by  Kurt Unger, Dept. of Ecology

 Climate Impacts Group -  Columbia River Basin    WACCIA Report

 U.S. Climate Change Science Program - May 2008 Report

See what Ecology is doing to address Climate Change in Washington

For more information please contact:

Mark Schuppe, Operations Manager
Office of Columbia River
(509) 454-4238 or .