USGS calculates loads and trends through 2021 for the nine major rivers entering Chesapeake Bay Active
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: 1985-2021 (long term) and 2012-2021 (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%.
For more information
The USGS data release can be accessed here:
Mason, C.A., and Soroka, A.M., 2022, Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay River Input Monitoring stations: Water years 1985-2021: U.S. Geological Survey data release, https://doi.org/10.5066/P90CZJ1Y.
A more detailed summary of the results, RIM Load and Trend Summary 2021.pdf, is available under Attached Files on the link above.
- Overview
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.
Sources/Usage: Public Domain. View Media DetailsFigure 1. Location of the nine River Input Monitoring (RIM) stations in the Chesapeake Bay watershed. Major Findings
Changes in loads for nitrogen, phosphorus, and suspended sediment were estimated for two time periods: 1985-2021 (long term) and 2012-2021 (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%.
Sources/Usage: Public Domain. View Media DetailsTable 1. Summary of long-term (1985-2021) and short-term (2012-2021) trends in nitrogen, phosphorus, and suspended-sediment loads for the River Input Monitoring stations. “Improving” or “Degrading” trends are classified as likelihood estimates greater than or equal to 67 percent, whereas “No trend” estimates are greater than 33 and less than 67 percent. For more information
The USGS data release can be accessed here:
Mason, C.A., and Soroka, A.M., 2022, Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay River Input Monitoring stations: Water years 1985-2021: U.S. Geological Survey data release, https://doi.org/10.5066/P90CZJ1Y.A more detailed summary of the results, RIM Load and Trend Summary 2021.pdf, is available under Attached Files on the link above.
- Data