Pacific Northwest Research Station

Stream Chemistry Network

Forested headwater streams provide high-quality water as one of their important ecosystem services. Changes in land use and vegetation cover, as well as natural processes and disturbances, affect water quality in these streams. Disturbances such as logging or wildfires have been shown to increase stream nutrient concentrations and fluxes, stream temperatures, and sediment output. Because disturbances cascade through ecosystems to affect downstream users, especially in watersheds that serve as sources of drinking water for communities, national and regional water quality standards have been established to protect water quality during forest management activities. Increased understanding of natural water quality variability as well as responses to forest disturbance across a range of environmental conditions throughout the nation are needed for management of forest lands and setting goals to meet water quality criteria.

To meet this need, stream biochemistry data have been collected for decades in watersheds in the Experimental Forests and Ranges (EFR) network. This economic recovery project, led by Pacific Northwest (PNW) Research Station scientist Sherri Johnson in conjunction with Charles Rhoades (Rocky Mountain Research Station) and Stephen Sebestyen (Northern Research Station), is a collaborative effort between U.S. Forest Service Research and Development, universities, and the forest industry to compile and evaluate long-term water quality data from EFRs across the country. The long-term data from reference and managed forests are being used to inform the development of the Environmental Protection Agency’s (EPA) water quality criteria across states, as well as to evaluate the effects of natural and anthropogenic forest disturbances on various chemical and physical components of water exported from river basins. A Web-based interactive program is being created to make the data easily available to researchers and the public. Other partners include the National Science Foundation’s Long-Term Ecological Research (LTER) network, and the National Council for Air and Stream Improvement (NCASI), a research institute that focuses on environmental topics of interest to the forest products industry.

Development, organization, and population of the data base have progressed well, and a Web-based system for accessing the data has been completed. The information provided the basis for research articles on four topics:

• Long-term stream nitrogen trends in undisturbed watersheds.
• The relation between seasonal stream chemistry and proposed numeric nutrient criteria.
• Stream chemistry responses to natural and anthropogenic disturbances.
• Determination of best methods to compare stream chemistry fluxes across a broad range of long-term data sets and research sites.

For more information, please see: http://www.fsl.orst.edu/efr/.