Total Nutrient and Sediment Loads, Trends, Yields, and Nontidal Water-Quality Indicators for Selected Nontidal Stations, Chesapeake Bay Watershed, 1985-2011.

摘要

The U.S. Geological Survey, in cooperation with Chesapeake Bay Program (CBP) partners, routinely reports long-term concentration trends and monthly and annual constituent loads for stream water-quality monitoring stations across the Chesapeake Bay watershed. This report documents flow-adjusted trends in sediment and total nitrogen and phosphorus concentrations for 31 stations in the years 1985-2011 and for 32 stations in the years 2002-2011. Sediment and total nitrogen and phosphorus yields for 65 stations are presented for the years 2006-2011. A combined nontidal water-quality indicator (based on both trends and yields) indicates there are more stations classified as improving water-quality trend and a low yield than degrading water-quality trend and a high yield for total nitrogen. The same type of 2-way classification for total phosphorus and sediment results in equal numbers of stations in each indicator class.