Biological Community

Biological community samples (fish, invertebrates, algae) are collected in streams and rivers as part of ecological studies in the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program. Information from these ecological studies, together with chemical and physical data, provide an integrated assessment of water quality at local, regional, and national scales. During the program's first decade of operation (1991 - 2001), ecological studies were conducted to assess the occurrence and distribution of algal, invertebrate, and fish communities in about 59 study units (Gilliom and others, 1995). In the second decade of the program (2001 - 2011), biological community samples will be collected at selected sites to provide long-term trends monitoring. Ecological studies are also part of nationally guided studies addressing selected water-quality issues such as the effects of watershed urbanization on nutrient enrichment and stream ecosystems.