Surface Water
Surface-water sites were selected to measure how natural factors and human activities affect water quality. During Cycle I (1991-2000) of the NAWQA study, 11 sites were in the White River (WHIT) Study Unit and 8 sites were in the Great and Little Miami (MIAM) Study Unit. These sites represent the dominant hydrologic, geologic, and land-use settings in the Study Unit. Two types of sites were sampled in Cycle I: basic and intensive. Intensive sites were sampled more frequently than the basic sites and were sampled for more pesticides.
Five of the intensive sites sampled during Cycle I are scheduled to be resampled in Cycle II (2001-2010) to measure how water chemistry has changed in the past 10 years. The five sites include two basins representing agricultural land use, two basins representing urban land use, and one large river site that integrates all the land use in the White River Basin. A sixth site to be sampled serves as a reference site within the Eastern Corn Belt ecoregion. This site, Big Walnut Creek near Roachdale, Indiana, was selected because it represents exceptional ecological community typical of reference conditions, even though it is not free of the effects of human activity. Constituents sampled include nutrients, heavily used pesticides, polar pesticides, major metabolites of triazines and acetanalides, volatile organic compounds, and glyphosate.
To access water-chemistry data from Cycles I and II of the NAWQA study for the WHIT and MIAM Study Units, go to the NAWQA Data Warehouse.