Establishing a Collaborative and Multipurpose Long Term National Reference Site Network for Freshwater Streams in the United States

Bill Wilber*, Jeff Deacon, Peter Murdoch, Mark Nilles and Mike Norris
U.S. Geological Survey

The U.S. Geological Survey is developing a plan for a collaborative and multi-purpose long-term national reference site network for freshwater streams in the United States to address increasing needs for information on the status and trends in streamflow and water quality of relatively unimpaired watersheds. An organizational structure similar to that of the National Atmospheric Deposition Program would help facilitate interagency collaboration to develop and encourage use of nationally-consistent field and laboratory protocols, procedures for quality assurance and quality control, and data management. A three tiered network design would consist of: 1) 75 to 100 minimally impaired watersheds geographically distributed across Level 2 ecoregions where realtime monitoring of hydrologic, climatic, and landscape variables would occur; 2) periodic synoptic sampling of a larger number of sites to provide higher spatial resolution of stream conditions; and 3) remote sensing and modeling to assist with extrapolation and forecasting. One approach for evaluating a network design involves characterizing the natural setting and anthropogenic disturbances of pre-designated “reference” basins relative to all Hydrologic Unit Code 10 basins within a Level 2 ecoregion. This will allow for placing existing and candidate reference basins in a larger environmental context and provide a mechanism for individual scientists and agencies to evaluate the suitability of different sites for achieving mission-specific goals. Initially this effort will include: an inventory of existing sites and data used by different agencies to characterize reference conditions and an analysis of existing and discontinued monitoring sites to determine where new sampling may be effective for enhancing a national reference site network. Data from this network will quantify reference conditions for a broad suite of chemical and ecological attributes that respond to anthropogenic and climate-related effects on water quality at watershed, regional, and national scales. For example, network data would be used in quantifying long-term trends for select constituents on a regional and national basis; establishing background concentrations for select constituents to guide the establishment of water-quality criteria; providing a benchmark for understanding environmental stressors on aquatic communities; quantifying episodic events with sufficient sampling frequency; and providing access to data for reference water-quality conditions. Increased collaboration among Federal and State agencies is a key mechanism for the success and support of a national reference site network that ultimately serves multiple agency objectives and program goals.

*Corresponding Author: 703-648-6878,