Maps

This map displays the segmentsheds used by the Chesapeake Bay Program. A segmentshed is the discrete land area that drains into each of the 92 Bay Program segments (see map of Chesapeake Bay Segmentation Scheme) that have TMDLs associated with them.

This map displays the segmentsheds used by the Chesapeake Bay Program. A segmentshed is the discrete land area that drains into each of the 92 Bay Program segments (see map of Chesapeake Bay Segmentation Scheme) that have TMDLs associated with them.

This map shows the location of point sources of nutrient pollution and priority agricultural watersheds as identified by the Chesapeake Bay Program with input from the Natural Resources Conservation Service (NRCS). Point sources include both monitored and estimated data submitted from or approved by each jurisdiction. Priority agricultural watersheds include SPARROW catchments ranking in the top quartile for delivered loads of nitrogen or phosphorus from agricultural sources normalized by the total amount of agricultural areas within the catchment. The priority areas were further refined to emphasize high loading areas which also contained potential agriculture-related water quality impairments based on individual state 303d (impaired waters) lists.

This map shows the location of point sources of nutrient pollution and priority agricultural watersheds as identified by the Chesapeake Bay Program with input from the Natural Resources Conservation Service (NRCS). Point sources include both monitored and estimated data submitted from or approved by each jurisdiction. Priority agricultural watersheds include SPARROW catchments ranking in the top quartile for delivered loads of nitrogen or phosphorus from agricultural sources normalized by the total amount of agricultural areas within the catchment. The priority areas were further refined to emphasize high loading areas which also contained potential agriculture-related water quality impairments based on individual state 303d (impaired waters) lists.

This map shows a quartile ranking within Maryland of the delivered yield (load per area) of Total Nitrogen from urban sources. Delivered yield is the amount of nutrient that is generated locally for each stream reach and weighted by the amount of in-stream loss that would occur with transport from the reach to Chesapeake Bay. The cumulative loss of nutrients from generation to delivery to the Bay is dependent on the travel time and instream-loss rate of each individual reach. This map shows estimates of Total Nitrogen based on mean conditions for the late 1990's time period using the SPARROW model from USGS. SPARROW, or SPAtially Referenced Regressions On Watershed (SPARROW) attributes, uses a nonlinear regression approach to spatially relate nutrient sources and watershed characteristics to nutrient loads of streams throughout the Chesapeake Bay watershed.

This map shows the percent of the Water Clarity goal achieved for each Chesapeake Bay Segment in 2010.

Over the past 24 years, sediment concentration trends show mixed responses among the monitoring sites with the majority of results being not significant or downward. The trend results indicate that in some locations, management actions, such as erosion and runoff controls have reduced sediment concentrations in streams. The flow-adjusted trends indicator is calculated, and published annually by the U.S. Geological Survey as part of a larger effort to determine loads and trends in nutrient and sediment concentrations and streamflow in the Chesapeake Bay watershed. A complete description of data analysis methods can be found in Langland, M. J., and others, Changes in streamflow and water quality in selected nontidal basins in the Chesapeake Bay watershed, 1985-2004: U.S. Geological Survey Scientific Investigations Report 2006-5178, 75 p., available online at http://pubs.usgs.gov/sir/2006/5178/

Over the past 24 years, phosphorus concentration trends are downward at the majority of long-term monitoring sites within the Bay watershed. The trend results indicate that in many locations, management actions, such as improved wastewater treatment and nonpoint-source pollution controls (i.e. urban stormwater runoff and agricultural runoff controls), have reduced phosphorus concentrations in streams. The flow-adjusted trends indicator is calculated, and published annually by the U.S. Geological Survey as part of a larger effort to determine loads and trends in nutrient and sediment concentrations and streamflow in the Chesapeake Bay watershed. A complete description of data analysis methods can be found in Langland, M. J., and others, Changes in streamflow and water quality in selected nontidal basins in the Chesapeake Bay watershed, 1985-2004: U.S. Geological Survey Scientific Investigations Report 2006-5178, 75 p., available online at http://pubs.usgs.gov/sir/2006/5178/

Over the past 24 years, nitrogen concentration trends are downward at the majority of long-term monitoring sites within the Bay watershed. The trend results indicate that in many locations, management actions, such as improved wastewater treatment and nonpoint-source pollution controls (i.e. urban stormwater runoff and agricultural runoff controls), have reduced nitrogen concentrations in streams. The flow-adjusted trends indicator is calculated, and published annually by the U.S. Geological Survey as part of a larger effort to determine loads and trends in nutrient and sediment concentrations and streamflow in the Chesapeake Bay watershed. A complete description of data analysis methods can be found in Langland, M. J., and others, Changes in streamflow and water quality in selected nontidal basins in the Chesapeake Bay watershed, 1985-2004: U.S. Geological Survey Scientific Investigations Report 2006-5178, 75 p., available online at http://pubs.usgs.gov/sir/2006/5178/.

Over the past 10 years, sediment concentration trends show mixed responses among the monitoring sites with the majority of results being not significant, 5 sites indicate improving conditions while 6 sites indicate degrading conditions. The trend results indicate that in some locations, management actions, such as erosion and runoff controls may have contributed to reducing sediment concentrations in streams. The short-term flow-adjusted trends and yields indicator is calculated, and results and maps are published annually by the U.S. Geological Survey as part of a larger effort to determine loads and trends in nutrient and sediment concentrations and streamflow in the Chesapeake Bay watershed.