Maps

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.

This map demonstrates the attainment status of those Chesapeake Bay Program monitoring segments that have dissolved oxygen standards for the Open Water, Deep Water, and Deep Channel designated use during the 2010-2012 assessment period.

Tidal waters that are impaired for part or all of the indicated Bay segment by toxic chemicals based on each state's implementation of the Clean Water Act.

This map demonstrates the attainment status of those Chesapeake Bay Program monitoring segments that have numeric chlorophyll a standards for the Open Water designated use during the 2009-2011 assessment period.

This map demonstrates the attainment status of those Chesapeake Bay Program monitoring segments that have dissolved oxygen standards for the Open Water, Deep Water, and Deep Channel designated use during the 2009-2011 assessment period.

The 2012 Dissolved Oxygen Indicator showing Percent of Goal Achieved using the three year analysis method.

Average yields for total sediment (TS) were estimated for the last five years at 65 sites and classified into thirds as high, medium, and low. While the distribution was spatially variable, there were some general patterns in location. Generally, spatial patterns not very discernible for sediment except for higher yields in the middle of the watershed, areas where total nitrogen and total phosphorus yields are also highest. The lowest yields are generally in the western areas of the Bay watershed, an area dominated by forests and on the Eastern Shore of Maryland and Delaware.

Average yields for total phosphorus (TP) were estimated for the last five years at 65 sites and classified into thirds as high, medium, and low. While the distribution was spatially variable, there were some general patterns in location. Generally, higher yields for TP are dominant in the middle of the watershed, areas that also coincide with large urban and agricultural land uses. The lowest yields are generally in the western areas of the Bay watershed, an area dominated by forests.

Average yields for total nitrogen (TN) were estimated for the last five years at 65 sites and classified into thirds as high, medium, and low. While the distribution was spatially variable, there were some general patterns in location. Generally, higher yields for TN are dominant in the middle of the watershed, areas that also coincide with large urban and agricultural land uses. The lowest yields are generally in the Virginia watersheds.

Over the past 10 years, the majority of sediment concentration trends are non-significant monitoring at sites within the Bay watershed with many sites showing degrading condition and only a few are improving. The trend results indicate that at some monitored locations, short-term trends indicate that management actions, such as efforts to curb erosion and runoff have reduced concentrations of sediment. While these reductions provide evidence of improving conditions in some upstream areas, additional reductions will be needed to have healthier streams and meet water-quality goals for the Bay.