Integrated Crop Management

Water quality in the eastern Iowa basins

This article summarizes major findings about nutrients in surface and groundwater in the eastern Iowa basins (see map) between 1996 and 1998. The data were collected as part of the U.S. Geological Survey (USGS) National Water-Quality Assessment Program (NAWQA). Water quality is discussed in terms of local and regional issues and compared with conditions found in all 36 National NAWQA study areas assessed to date. Findings are explained in the context of selected national U.S. Environmental Protection Agency (EPA) benchmarks, such as those for drinking water quality and the protection of aquatic organisms.

The Eastern Iowa Basins Study Unit includes the Wapsipinicon, Cedar, Iowa, and Skunk River basins and covers approximately 19,500 square miles in eastern Iowa and southern Minnesota. More than 90 percent of the land in the study unit is used for agricultural purposes. Forested areas account for only 4 percent of the land area.

Eastern Iowa Basins

Stream and river highlights

Nitrogen (N) and phosphorus (P) concentrations in streams in the Eastern Iowa Basins Study Unit rank as some of the highest in the Corn Belt, as well as the nation, and were higher than the drinking water standard in many samples. These conditions reflect the intensive use of the land for growing crops and dense populations of livestock in some basins.

Ground water highlights

Compared with surface water, groundwater in the eastern Iowa basins had substantially lower nutrient concentrations.

For more information on the Eastern Iowa Basins Report, go to the USGS NAWQA website [1] or contact USGS State Representative, U.S. Geological Survey, Water Resources Division, P.O. Box 1230, 400 South Clinton St., Rm. 269, Iowa City, IA 52244, E-mail: [2]

Some of the information in this article was taken from Water Quality in the Eastern Iowa Basins, Iowa and Minnesota, 1996-98 [3]. U.S. Department of the Interior-U.S. Geological Survey Circular 1210.

This article originally appeared on pages 185-186 of the IC-486(23) -- October 22, 2001 issue.

Source URL: