Evaluating Potential Water Quality Impairments on National Forest Priority Watersheds Using Estimates of Atmospheric Deposition

David Levinson1, Anita Rose2 and Rich Pouyat3

The U.S. Forest Service Watershed Condition Framework (WCF) is a nationally consistent reconnaissance-level approach for assessing and classifying watershed condition, using a comprehensive set of 12 indicators that are surrogate variables representing the underlying ecological, hydrological, and geomorphic functions and processes that affect watershed condition. Primary emphasis of the WCF is on aquatic and terrestrial processes and conditions that Forest Service management activities have on stream, riparian and aquatic habitat. As part of the WCF, National Forests designate “Priority Watersheds” where a variety of land management treatments are planned and implemented. One of the primary aquatic indicators of the WCF is water quality, but measuring and monitoring water quality impacts has been difficult since many of the almost 300 Priority Watersheds are located in headwater regions on National Forests. Initial steps are under way to collocate both water and air monitoring on Priority Watersheds, to improve understanding of water quality impairments due to atmospheric deposition. A primary question is understanding when air deposition is coupled with water quality, and when they are decoupled, and why?  A specific concern is Nitrogen (N) deposition, since it impacts large parts of the U.S., and initial efforts will be to use N deposition estimates to identify a subset of Priority Watersheds with potential water quality impairments for collocating air and water monitoring.


1US Forest Service, dlevinson@fs.fed.us
2US Forest Service, anitarose@fs.fed.us
3US Forest Service, rpouyat@fs.fed.us