Most people do not realize that more than half the water in the United States comes from watersheds managed on forests. Used in homes, on ranches, in industry and for energy production, water resources in forests provide important services to people, as well as habitat for a wide variety of aquatic life. Our rapidly changing climate, however, is challenging our watersheds with both wet and dry extremes – more severe droughts, more frequent and larger floods, more soil moisture stress and lower stream flows during the dry season, less of a snowpack reservoir, and other effects. In a unique pilot project, 11 national forests around the country are assessing the vulnerability of their water resources and watersheds to such changes.
A watershed is the area of land that drains to a particular point along a stream. Streams each have their own watersheds and they come in all shapes and sizes. Watersheds may be quite large, and include towns, forests or mountains. Their great variance means their vulnerability to the effects of climate change differs greatly as well. Understanding these complex landscapes and the specific factors that distinguish each is a vital step towards restoring them and making them more resilient to climate change. National forests participating in the Pilot Watershed Vulnerability Assessments project are identifying important water resources in their areas, and assessing watershed sensitivity and exposure to climate change. Scientists will consider and map such aspects as the impact on fish and other aquatic species, and the effects of water diversions (dams, for example), reductions in snow storage, and increasing flood magnitude and frequency. Based on their findings, they are providing recommendations on responses each forest can take for healthier, more resilient watersheds, so that the services and values we expect from these precious places are maintained.
Hydrologist Michael Furniss of the USDA Forest Service’s Pacific Northwest Research Station is the chair of the project steering committee. “We expect the first-cut assessments this fall,” says Furniss, “and we’ll have some advice for others doing this work, based on our experiences.” The pilot products and lessons learned will contribute to guidance for a comprehensive approach to assessing vulnerability of national forest waters and watersheds to climate change, and to the development of effective adaptation strategies. Participating national forests are the Gallatin National Forest (NF) and Helena NF in Montana; White River NF and Grand Mesa, Uncompahgre, and Gunnison NFs in Colorado; Coconino NF in Arizona; Sawtooth NF in Idaho; Shasta-Trinity NF in California; Umatilla NF in Oregon; Ouachita NF in Arkansas; Chequamegon-Nicolet NF in Wisconsin; and the Chugach NF in Alaska.