Updated 2020 Nutrient and Suspended-Sediment Trends for the Nine Major Rivers Entering the Chesapeake Bay

Science Center Objects

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.

Location of the nine River Input Monitoring (RIM) stations in the Chesapeake Bay watershed

Figure 1. Location of the nine River Input Monitoring (RIM) stations in the Chesapeake Bay watershed.

From Mason and others, 2021

Major Findings

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.

Trends in nitrogen, phosphorus, and suspended-sediment loads for RIM

Table 1. Summary of long-term (1985-2020) and short-term (2011-2020) 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.

From Mason and others, 2021

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

 

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

 

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