Skip to main content
U.S. flag

An official website of the United States government

Geonarrative: Nontidal Network Mapper

August 13, 2022

Release notes

Updates to this application are expected every two years to coincide with the release of the latest short-term nontidal network data. Visit the Chesapeake Bay Water-Quality Loads and Trends web page for additional information or to access the data used in the application.

  • August 2022 - updated to share 2011-2020 water year results

  • July 2020 - initial release, 2009-2018 water year results


About this tool

Chesapeake Bay watershed map showing the distribution of nontidal network stations.
Figure 1. A map of the Chesapeake Bay watershed showing the distribution of nontidal network  stations, as of 2020. 

The Nontidal Network Mapper geonarrative shares the short-term nutrient and suspended-sediment load and trend results for the Chesapeake Bay Program’s nontidal network (Figure 1).

Data collected from the 123 nontidal network stations are analyzed by the U.S. Geological Survey every two years and are used to quantify the changes in nutrient (primarily nitrogen and phosphorus) and suspended-sediment loads. The results are used by the Chesapeake Bay Program partnership to help assess response in nontidal rivers and streams to nutrient and sediment reduction efforts.

The mapper provides the primary findings for nitrogen, phosphorus, and sediment trends and gives the user tools to further examine the results for river basins and individual sites.


Tool features

For each constituent (total nitrogen, total phosphorus, and suspended sediment), interactive maps, graphs, and query tools allow users to view both site-specific load, trend, and yield information as well as patterns across the Chesapeake Bay and its seven major watersheds. 

A screenshot showing a portion of the nontidal mapper, which shares the short-term nontidal network water quality results.
Figure 2. Nontidal network mapper screenshot (August 2022).

For more information:

For more information on the nontidal network: Chesapeake Bay Water-Quality Loads and Trends