Updated 2020 Nutrient and Suspended-Sediment Trends for the Nine Major Rivers Entering the Chesapeake Bay
Issue: The amount of nutrients and suspended sediment entering the Chesapeake Bay affect water-quality conditions in tidal waters. Excess nutrients contribute to algal blooms that lower the oxygen levels in tidal waters that are important for fish and shellfish. The algal blooms, along with suspended sediment, also decrease visibility in shallow waters for submerged aquatic grasses. The grasses are important because they put oxygen into tidal waters, provide habitat for fish and crabs, and food for waterfowl.
USGS Study
The Chesapeake Bay River Input Monitoring (RIM) network consists of monitoring stations located near the nontidal-tidal interface of the nine largest rivers in the Chesapeake Bay watershed (fig. 1). These rivers are the Susquehanna, Potomac, James, Rappahannock, Appomattox, Pamunkey, Mattaponi, Patuxent, and Choptank. The RIM stations are located near U.S. Geological Survey (USGS) streamgages to permit estimates of nutrient and suspended sediment loadings and trends of the amount of constituents delivered downstream. The USGS partners with the Maryland Department of Natural Resources, and the Virginia Department of Environmental Quality for the collection and analysis of RIM network data.
Major Findings
Changes in loads for nitrogen, phosphorus, and suspended sediment were estimated for two time periods: 1985-2020 (long term) and 2011-2020 (short term) and are summarized in table 1. The trend results are summarized as “improving” (loads are decreasing over time); “degrading” (loads are increasing over time),” and “no trend” (a statistically significant trend was not detected). Increasing and degrading trends are classified as likelihood estimates greater than or equal to 67%, whereas no trend estimates are greater than 33% and less than 67%.
Management Applications
The Chesapeake Bay partnership uses results from RIM stations to help understand changes in estuary water-quality conditions.
For more information
More information on the RIM results:
Summary of Nitrogen, Phosphorus, and Suspended-Sediment Loads and Trends Measured at the Nine Chesapeake Bay River Input Monitoring Stations: Water Year 2020 Update by Chris Mason, Alex Soroka, Doug Moyer, and Joel Blomquist.
Mason, C.A., Soroka, A.M., Moyer, D.L. and Blomquist, J.D., 2021, Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay River Input Monitoring stations: Water years 1985-2020: U.S. Geological Survey data release, doi.org/10.5066/P93PZGMM.
For more information on the RIM results and nontidal-water quality network:
Changes in Streamflow and Water Quality in Selected Nontidal Basins in the Chesapeake Bay Watershed
Read the Bay Journal article: Nutrient pollution in Bay’s 3 largest rivers trending downward
Contacts
Chris Mason (camason@usgs.gov)
Alex Soroka (asoroka@usgs.gov)
Doug Moyer (dlmoyer@usgs.gov)
Joel Blomquist (jdblomqu@usgs.gov)
Posted October 5, 2021
Nutrient pollution in Bay’s 3 largest rivers trending downward
Bay Journal — by Karl Blankenship — December 2, 2021
Issue: The amount of nutrients and suspended sediment entering the Chesapeake Bay affect water-quality conditions in tidal waters. Excess nutrients contribute to algal blooms that lower the oxygen levels in tidal waters that are important for fish and shellfish. The algal blooms, along with suspended sediment, also decrease visibility in shallow waters for submerged aquatic grasses. The grasses are important because they put oxygen into tidal waters, provide habitat for fish and crabs, and food for waterfowl.
USGS Study
The Chesapeake Bay River Input Monitoring (RIM) network consists of monitoring stations located near the nontidal-tidal interface of the nine largest rivers in the Chesapeake Bay watershed (fig. 1). These rivers are the Susquehanna, Potomac, James, Rappahannock, Appomattox, Pamunkey, Mattaponi, Patuxent, and Choptank. The RIM stations are located near U.S. Geological Survey (USGS) streamgages to permit estimates of nutrient and suspended sediment loadings and trends of the amount of constituents delivered downstream. The USGS partners with the Maryland Department of Natural Resources, and the Virginia Department of Environmental Quality for the collection and analysis of RIM network data.
Major Findings
Changes in loads for nitrogen, phosphorus, and suspended sediment were estimated for two time periods: 1985-2020 (long term) and 2011-2020 (short term) and are summarized in table 1. The trend results are summarized as “improving” (loads are decreasing over time); “degrading” (loads are increasing over time),” and “no trend” (a statistically significant trend was not detected). Increasing and degrading trends are classified as likelihood estimates greater than or equal to 67%, whereas no trend estimates are greater than 33% and less than 67%.
Management Applications
The Chesapeake Bay partnership uses results from RIM stations to help understand changes in estuary water-quality conditions.
For more information
More information on the RIM results:
Summary of Nitrogen, Phosphorus, and Suspended-Sediment Loads and Trends Measured at the Nine Chesapeake Bay River Input Monitoring Stations: Water Year 2020 Update by Chris Mason, Alex Soroka, Doug Moyer, and Joel Blomquist.
Mason, C.A., Soroka, A.M., Moyer, D.L. and Blomquist, J.D., 2021, Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay River Input Monitoring stations: Water years 1985-2020: U.S. Geological Survey data release, doi.org/10.5066/P93PZGMM.
For more information on the RIM results and nontidal-water quality network:
Changes in Streamflow and Water Quality in Selected Nontidal Basins in the Chesapeake Bay Watershed
Read the Bay Journal article: Nutrient pollution in Bay’s 3 largest rivers trending downward
Contacts
Chris Mason (camason@usgs.gov)
Alex Soroka (asoroka@usgs.gov)
Doug Moyer (dlmoyer@usgs.gov)
Joel Blomquist (jdblomqu@usgs.gov)
Posted October 5, 2021
Nutrient pollution in Bay’s 3 largest rivers trending downward
Bay Journal — by Karl Blankenship — December 2, 2021