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.