Maps

Long-term trends were computed by state partners using the Seasonal Kendall non-parametric technique for annual data collected from 1999-2013. Highly significant trends are indicated with triangles and possible trends are show with colored circles. Surface total nitrogen concentrations are decreasing/improving significantly at 41 stations, possibly decreasing at 16 stations, increasing/degrading significantly at 1 station, and possibly increasing at 1 station.

Long-term trends were computed by state partners using the Seasonal Kendall non-parametric technique for annual data collected from 1999-2013. Highly significant trends are indicated with triangles and possible trends are show with colored circles. Surface chlorophyll-a concentrations are decreasing/improving significantly at 2 stations, possibly decreasing at 7 stations, increasing/degrading significantly at 25 stations, and possibly increasing at 16 stations.

This map demonstrates the attainment status of those Chesapeake Bay Program monitoring segments that have SAV and/or water clarity standards for the Shallow Water Bay Grasses designated use during the 2010-2012 assessment period.

Watershed Yield: Sediment yields ranged from 9.3 to 648 tons per square mile. Each of the 17 sites in the high yield category carries more than 200 tons of sediment per square mile of watershed. High yielding sites are spatially dispersed across the Susquehanna, Potomac and Rappahannock watersheds. The lowest sediment yielding sits are located on the Eastern Shore and the York River Basin.

Watershed Yield: Total Phosphorus yields ranged from 0.036 to 0.57 tons per square mile. Each of the 17 sites in the high yield category carries more than 0.19 tons of phosphorus per square mile of watershed. High yielding sites were found in the Eastern Shore, Susquehanna, Potomac, and Rappahannock Watersheds. The lowest yields are generally in the western areas of the Bay watershed and the York River Basin.

Watershed Yield: Total Nitrogen yields ranged from 0.33 to 9.87 tons per square mile. Each of the 17 sites in the high yield category carries more than 3.4 tons of nitrogen per square mile of watershed. These sites are generally located on the Eastern Shore, Lower Susquehanna and Northern Potomac Watersheds. The lowest yields, which are less than 1.2 tons per square mile, are generally in the Upper Potomac and Southern Virginia Rivers.

Short Term Trend: Over the past 10 years, 49 percent of sites show little change while 41 percent show degrading flow-adjusted sediment concentrations. Between 2003 and 2012: - 4 out of 39 sites show improving flow-adjusted trends for sediment concentrations, - 16 site shows degrading trends, and - 19 sites show small changes that are not statistically significant.

Short Term Trend: Over the past 10 years, 63 percent of the monitoring stations show little or no change in flow-adjusted phosphorus concentrations. Between 2003 and 2012: - 9 out of 43 sites show improving flow-adjusted trends for phosphorus concentrations, - 7 site shows degrading trends, and - 27 sites show small changes that are not statistically significant.

Short Term Trend: Over the past 10 years, 54 percent of the monitoring stations show improving flow-adjusted nitrogen concentrations. Only one site showed degrading nitrogen conditions. Between 2003 and 2012: - 25 out of 46 sites show improving flow-adjusted trends for nitrogen concentrations, - 1 site shows degrading trends, and - 20 sites show small changes that are not statistically significant.

Long Term Trend: Forty-four percent of long-term stream monitoring sites in the Chesapeake Bay Watershed show little change in flow-adjusted concentrations of sediment. The remaining sites were evenly split between improving and degrading conditions. Between 1985 and 2012: - 8 out of 29 sites show improving flow-adjusted trends for sediment concentrations, - 8 sites show degrading trends, and - 13 sites show small changes that are not statistically significant.