Deliver Benefits to the Public

The future of forested watersheds

Forested watersheds provide clean drinking water to millions of people. Nantahala National Forest, Mooney Falls, Macon, North Carolina. Photo courtesy of Brian Greer.

NORTH CAROLINA – Forests provide high quality and dependable supplies of surface water. More than 19 million people in the Southeast get at least some of their drinking water from national forests, as a USDA Forest Service research revealed.

“Some models project that urban land uses in parts of the Southeast will double by 2060,” says James Vose, a project leader at the SRS Center for Integrated Forest Science. “Average annual temperatures are projected to increase by 2 to 4 degrees Celsius. Precipitation projections are much more uncertain, but many of the models project greater variability; that is, dry years become drier and wet years become wetter.”

Understanding how such changes could impact water supplies has been a major challenge.

Vose is part of an interdisciplinary research team devoted to untangling the potential impacts. The team recently published initial findings in the journal EcohydrologyKatherine Martin, a research fellow with the Center and an assistant professor at North Carolina State University, was the senior author of the study.

The scientists modeled three watersheds in the Yadkin–Pee Dee River Basin, which stretches from the mountains of Virginia to the coast of South Carolina. The basin, which drains over 7,000 square miles, includes major cities, including much of the Charlotte metropolitan area.

“Research team members John Coulston and David Wear developed a new model for projecting future land use patterns at small spatial scales,” says Vose. “The model allows us to understand how fine-scale land use patterns impact hydrologic processes and provided information at scales small enough to be useful for city planners and other decision makers.” The scientists modeled watersheds that represented a range of land uses, from the urban to the heavily forested.

Water managers and city planners can use the model to see where forest loss might have the greatest impact. Knowing which forests are vulnerable can help guide management and policy responses.