Water Quality in Indiana: Trends in Concentrations of Selected Nutrients, Metals, and Ions in Streams, 2000-10.

摘要

Water quality in Indiana streams generally improved during the 2000-10 study period, based on trends in selected nutrients, metals, and ions. This study combined water-quality data from the Indiana Fixed Station Monitoring Program (FSMP) with streamflow data from nearby U.S. Geological Survey streamgages. A parametric time-series model, QWTREND, was used to develop streamflow-adjusted constituent concentrations, to adjust for seasonal variance and serial correlation, and to identify trends independent of streamflowrelated variability. This study examined 7,345 water samples from 57 FSMP sites for 11 years. Concentration trends were analyzed for 12 constituentsthe nutrients nitrate, organic nitrogen, and phosphorus; suspended solids; the metals copper, iron, lead, and zinc; the ions chloride, and sulfate together with hardness as a measure of the calcium carbonate ion; and dissolved solids.