Flows of the future - how will climate change affect streamflows in the Pacific Northwest?
Abstract
Much of the water supply in the Pacific Northwest originates in national forests. It sustains the region's aquatic ecosystems, agriculture, hydroelectric power, and community water supplies. Understanding how climate change will affect water supply is one of the most pressing issues of our time. Substantial changes are projected in the types of precipitation (rain vs. snow) that will fall in the region, as are smaller, but potentially important, changes in the total annual precipitation. Combined with earlier snowmelt, these changes could cause decreased summer streamflows, and some high-elevation streams may dry up. These are the general projections, but each watershed has geological characteristics that will influence its response to changes in the type, timing, and amount of precipitation. Land managers want to know how specific watersheds are likely to respond, so scientists at the Pacific Northwest Research Station developed streamflow sensitivity maps for Oregon and Washington. Land managers across federal, state, and local governments; tribes; and private landowners now can see which watersheds have a higher risk of flooding in the future and which may be more sensitive to summer drought. With this information, land managers can develop tailored management plans for specific watersheds to adapt to the effects of climate change on streamflow.