Maps

Over the past decade, none of the monitoring sites in the Chesapeake Bay watershed have shown improving flow-adjusted trends in sediment concentrations. Between 2004 and 2013: zero sites have shown improving trends for sediment concentrations. Four sites—including the Appomattox, Choptank, Pamunkey and Patuxent rivers—have shown degrading trends. Five sites—including the James, Mattaponi, Potomac, Rappahannock and Susquehanna rivers—have shown minor changes that are not statistically significant.

One-third of the monitoring sites in the Chesapeake Bay watershed show improving long-term flow-adjusted trends in suspended sediment concentrations. Between 1985 and 2013: three out of nine sites—including the Choptank, Patuxent and Potomac rivers—have shown improving trends for sediment concentrations. One site—the Pamunkey River—has shown degrading trends. Five sites—including the Appomattox, James, Mattaponi, Rappahannock and Susquehanna rivers—have shown minor changes that are not statistically significant.

Over the past decade, none of the monitoring sites in the Chesapeake Bay watershed have shown improving flow-adjusted trends in phosphorus concentrations. Between 2004 and 2013: zero sites have shown improving trends for phosphorus concentrations. Two sites—including the Choptank and Susquehanna rivers—have shown degrading trends. Seven sites—including the Appomattox, James, Mattaponi, Pamunkey, Patuxent, Potomac and Rappahannock rivers—have shown minor changes that are not statistically significant.

One-third of the monitoring sites in the Chesapeake Bay watershed show improving long-term flow-adjusted trends in phosphorus concentrations. Between 1985 and 2013: three out of nine sites—including the James, Patuxent and Potomac rivers—have shown improving trends for phosphorus concentrations. Three sites— including the Appomattox, Choptank and Pamunkey rivers—have shown degrading trends. Three sites—including the Mattaponi, Rappahannock and Susquehanna rivers—have shown minor changes that are not statistically significant.

Over the past decade, one-third of the monitoring sites in the Chesapeake Bay watershed have shown improving flow-adjusted trends in nitrogen concentrations. Between 2004 and 2013: three out of nine sites—including the Patuxent, Potomac and Susquehanna rivers—have shown improving trends for nitrogen concentrations. One site—the Choptank River—has shown degrading trends. Five sites—including the Appomattox, James, Mattaponi, Rappahannock and Pamunkey rivers—have shown minor changes that are not statistically significant.

Fifty-five percent of monitoring sites in the Chesapeake Bay watershed show improving long-term flow-adjusted trends in nitrogen concentrations. Between 1985 and 2013: five out of nine sites—including the James, Patuxent, Potomac, Rappahannock and Susquehanna rivers—have shown improving trends for nitrogen concentrations. Two sites—including the Choptank and Pamunkey rivers—have shown degrading trends. Two sites—including the Appomattox and Mattaponi rivers—have shown minor changes that are not statistically significant.

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.