The U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Project will characterize the status and trends of water quality and aquatic ecosystems by monitoring ambient water-quality and ecological conditions through the newly established National Water Quality Network (NWQN) for Rivers and Streams. The NWQN is the primary source of data for the systematic annual reporting of ambient conditions nationally. The NWQN will also be a primary source of data for periodic interpretive analysis of status and trends for selected topics and regions, but these more intensive interpretive analyses will also utilize other sources of data, including compatible historical and current data from other monitoring networks and from NAWQA Regional Synoptic Studies (http://water.usgs.gov/nawqa/studies/msqa/index.html).
Primary objectives of the NWQN are to:
- determine the status and trends of loads and concentrations of contaminants, nutrients, and sediment in the Nation's large rivers, including loads to selected major estuaries;
- determine the status and trends of concentrations of contaminants, nutrients, and sediment for selected wadeable streams in selected land-use and environmental settings; and
- determine trends in ecological condition in relation to trends in contaminants, nutrients, sediment, and streamflow alteration for selected wadeable streams in selected land-use and environmental settings.
Relative to the NAWQA Cycle 2 network design (see Previous Network Information), the Cycle 3 network was modified to include the following:
- yearly sampling at all sites, rather than the rotational schedule used in the latter part of Cycle 2;
- integration of the large river and coastal sites monitored by the National Stream Quality Accounting Network (NASQAN) and the National Monitoring Network (NMN) . Sites operated by NAWQA, NASQAN, and the NMN (all three programs are now part of the NWQN for Rivers and Streams) use the same sampling protocols and laboratory methods, and samples are analyzed for the same constituents;
- integration of selected monitoring sites operated by the USGS Cooperative Water Program in areas of the country previously underrepresented by the NWQN;
- reduction of number of wadeable stream sites in urban, agricultural, and reference watersheds; and
- addition of real-time monitoring, including nitrate sensors, at a subset of sites.
The new NWQN includes 20 large river coastal sites, 41 large river inland sites, 30 wadeable stream reference sites, 10 wadeable stream urban sites, and 10 wadeable stream agricultural sites. An additional 3 large inland river monitoring sites from the USGS Cooperative Water Program are also included in this annual water-quality reporting Web site to be consistent with previous USGS studies of nutrient transport in the Mississippi-Atchafalaya River Basin.
The long term vision for this Web site is to include additional USGS and other Federal and State Agency water-quality monitoring stations that meet the needs of a national water-quality monitoring network. In addition to the inclusion of additional water-quality monitoring stations, additional constituents such as pesticides, carbon, and chloride, as well as information on aquatic ecology, will be incorporated into this Web site in subsequent versions.