Water-quality assessment of the Eastern Iowa Basins: Hydrologic and biologic data, October 1996 through September 1998

Hydrologic and biologic data collected from October 1996 through September 1998 in the Eastern Iowa Basins study unit of the U.S. Geological Survey National Water-Quality Assessment Program are presented in this report. Monthly data collected from 12 sites on rivers and streams included measurements of physical properties and determinations of the concentrations of nutrients, major ions, organic carbon, trace elements, suspended sediment, and dissolved pesticides. Fish-tissue samples were collected at two sites in September 1997 and analyzed for organochlorine pesticides. In addition, water-quality assessments were made at 25 sites as part of a synoptic study in August 1997 and May 1998. A ground-water study was conducted to evaluate the effects of agricultural and urban land use on the water quality of shallow alluvial aquifers in the study unit. Samples were collected and analyzed from wells in 31 agricultural and 30 urban land-use areas during June-August 1997. Samples were collected and analyzed from 32 domestic wells during June-July 1998 to provide a broad assessment of the water quality of shallow alluvial aquifers throughout the study unit. Samples were collected during August 1998 from 27 shallow monitoring wells completed in the Iowa River alluvial aquifer to evaluate the effects of changing land use on shallow ground-water quality. Ground-water samples were analyzed for physical properties, nutrients, major ions, organic carbon, trace elements, dissolved pesticides, volatile organic compounds, radon-222, and tritium.