Geonarrative: Nontidal Network Mapper
Nontidal Network Mapper (2014 to 2023)
The Nontidal Network Mapper shares the short-term water-year nutrient and suspended-sediment load and trend results for the Chesapeake Bay Program’s nontidal network.
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.
- March 2025 - updated to share 2014 to 2023 water year results
- August 2022 - updated to share 2011 to 2020 water year results
- July 2020 - initial release, 2009 to 2018 water year results
About this tool
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.

For more information:
Related
USGS develops tool to further examine nutrient and sediment trends in the Chesapeake Bay Watershed
Chesapeake Bay Water-Quality Loads and Trends
Access the data used in this application below.
Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay Nontidal Network stations: Water years 1985-2023
Application of a Weighted Regression Model for Reporting Nutrient and Sediment Concentrations, Fluxes, and Trends in Concentration and Flux for the Chesapeake Bay Nontidal Water-Quality Monitoring Network, Results Through Water Year 2012
A bootstrap method for estimating uncertainty of water quality trends
User guide to Exploration and Graphics for RivEr Trends (EGRET) and dataRetrieval: R packages for hydrologic data
Comparison of two regression-based approaches for determining nutrient and sediment fluxes and trends in the Chesapeake Bay watershed
Weighted regressions on time, discharge, and season (WRTDS), with an application to Chesapeake Bay River inputs
Load and trend results would not be possible without the ongoing monitoring and program support of our partners.
Related
USGS develops tool to further examine nutrient and sediment trends in the Chesapeake Bay Watershed
Chesapeake Bay Water-Quality Loads and Trends
Access the data used in this application below.
Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay Nontidal Network stations: Water years 1985-2023
Application of a Weighted Regression Model for Reporting Nutrient and Sediment Concentrations, Fluxes, and Trends in Concentration and Flux for the Chesapeake Bay Nontidal Water-Quality Monitoring Network, Results Through Water Year 2012
A bootstrap method for estimating uncertainty of water quality trends
User guide to Exploration and Graphics for RivEr Trends (EGRET) and dataRetrieval: R packages for hydrologic data
Comparison of two regression-based approaches for determining nutrient and sediment fluxes and trends in the Chesapeake Bay watershed
Weighted regressions on time, discharge, and season (WRTDS), with an application to Chesapeake Bay River inputs
Load and trend results would not be possible without the ongoing monitoring and program support of our partners.