Biology as an integrated component of the U.S. Geological Survey's National Water-Quality Assessment Program

The U.S. Geological Survey?s (USGS) National Water-Quality Assessment (NAWQA) Program is designed to integrate chemical, physical, and biological data to assess the status of and trends in the Nation?s water quality at local, regional, and national levels. The Program consists of 60 study units (major river basins and large parts of aquifers) located throughout the Nation (fig. 1). Data are collected at stream, river, and ground-water sites that represent the Nation?s mix of major natural and human factors that influence water quality. Biological data are collected from streams and rivers, and include (1) fish and other aquatic organisms whose tissues are analyzed for a wide array of chemical contaminants; (2) characterizations of algal, benthic invertebrate, and fish communities; and (3) characterizations of vegetation growing in streams and along streambanks. These biological data are collected in conjunction with physical (streamflow, characterizations of instream, bank, and flood-plain habitats) and chemical data.