Skip to Main Content U.S. Department of Energy
PNNL News Central

Watershed responses to forest practices studied

News Release

September 29, 1999 Share This!

RICHLAND, Wash. — A newly enhanced computer model may help forest managers design or modify forest roads, tree harvesting and other land-use activities based on effects to watersheds, streams and fish habitat.

Researchers at the Department of Energy's Pacific Northwest National Laboratory have expanded the capabilities of a watershed model to make it possible to explore economic and environmental trade-offs of various land-use activities. The research is sponsored by the National Council of the paper industry for Air and Stream Improvement, or NCASI, and the U.S. Forest Service.

Called the Geographic Information System-based Modeling System for Watershed Analysis, GISWA could provide information on how alternative practices can be used to help avoid altering a watershed's natural processes. Forest roads have received attention recently for their potential effects on watersheds and wildlife habitat. The Clinton Administration ordered a moratorium in February 1999 on road construction in some national forests.

"With the new enhancements, this model could be a valuable tool for planning new forest roads for the least effects to a watershed and its wildlife habitat," said Mark Wigmosta, a senior research engineer at Pacific Northwest. "The watershed analysis model is designed to make the link between cause and effect."

GISWA simulates hydrologic conditions at thousands of locations within a single watershed to provide a detailed representation of water movement. This includes flow below the ground's surface, called subsurface flow, which may be redistributed when trees are harvested or roads are built. Forest roads often cut into hillsides, which can divert subsurface flow into culverts. The culverts then can route greater amounts of water at a faster rate into streams if a direct connection exists between the culvert outlet and the stream.

"As a result, changing stream flow can erode channel banks, transport more sediment and alter the stream channels," Wigmosta said. "All of these factors have the potential to affect fish habitat."

GISWA is an updated version of a watershed model Wigmosta developed during his DOE-funded postgraduate work at the University of Washington in the early 1990s. The original model, called Distributed Hydrology-Soil-Vegetation Model, showed how climate change could effect hydrology and water resources.

In 1998, Pacific Northwest researchers integrated their version of the distributed watershed model with a version from the University of Washington. Then they incorporated a GIS-based modeling system and data on logging road networks and stream channels. In 1999, Pacific Northwest researchers began developing graphical user interfaces and preparing a user's manual. NCASI is expected to test the latest version in the next year then evaluate it for potential use by the forest industry.

Pacific Northwest also is applying GISWA, in conjunction with a regional climate model, to address climate issues in the United States and China.

Business inquiries on this or other PNNL technologies should be directed to 1-888-375-PNNL or e-mail:

Tags: Environment, Fundamental Science, Climate Science

PNNL LogoPacific Northwest National Laboratory draws on signature capabilities in chemistry, earth sciences, and data analytics to advance scientific discovery and create solutions to the nation's toughest challenges in energy resiliency and national security. Founded in 1965, PNNL is operated by Battelle for the U.S. Department of Energy's Office of Science. DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit PNNL's News Center. Follow us on Facebook, Instagram, LinkedIn and Twitter.

News Center


Additional Resources