U.S. Geological Survey’s National Water Quality Assessment Program

In 1991, the U.S. Geological Survey (USGS) begins the National Water Quality Assessment (NAWQA) Program, with the long term goals being to “describe the status of, and trends in, the quality of a large, representative part of the Nation’s surface- and ground-water resources and to identify the major natural and human factors that affect the quality of these resources” (USGS 1998). The emphasis of the NAWQA program is on regional scale, water-quality problems. This program will help provide a framework for understanding the regional and national water-quality conditions.

USGS is examining 60 hydrologic systems that include at least parts of most major river basins and aquifer systems in the nation. The Lower Illinois River Basin (LIRB) is selected as one of the study units to begin in 1994. The components to be studied are ground water, surface water, ecology, bed sediment, and fish tissue. Each will aid in assessing characteristics related to water quality.

Water quality issues identified by the LIRB NAWQA are sedimentation, toxic chemicals in sediments, high concentrations of nutrients and agricultural chemicals, and low dissolved oxygen. Sediment studies show that of the 300 backwater lakes that once existed, only 53 remain in 1991. Continued LIRB NAWQA examination will provide information critical to the management and restoration within the Illinois River basin.