Nontidal Monitoring Network Loads and Trends 2020
Explore Interactive Maps, View Results, and Query Data
RIM Data 2023
Most recent River Input Monitoring data for nitrogen, phosphorus, and suspended-sediment loads and trends.
NTN Data 2020
Most recent Nontidal Network data for nitrogen, phosphorus, and suspended-sediment loads and trends.
Summary of 2020 NTN Results
Nitrogen, Phosphorus, and Suspended-Sediment Loads and Trends Measured at the Chesapeake Bay Nontidal Network Stations for Water Years 2011–2020
Summary of 2023 RIM Results
Nitrogen, Phosphorus, and Suspended-Sediment Loads and Trends Measured at the Nine Chesapeake Bay River Input Monitoring Stations: Water Year 2022 Update
Access the most recent data gathered from the Chesapeake Bay Nontidal Monitoring Network, learn about the techniques used to collect this data, and read about the history of the Chesapeake Bay Nontidal Monitoring Program.
Nontidal Network (NTN) data refers to data from the 123 monitoring stations where nutrients and sediment are collected monthly and during storms.
River Input Monitoring (RIM) data refers to data from nine stations within the NTN network. This data is used to estimate the total amount of nutrient and sediment delivered to the Chesapeake Bay annually.
This page provides data access to our partners, cooperators, decision-makers, water quality managers, and scientists who need to access the latest data on nutrient and sediment loading to the Chesapeake Bay.
Most Recent NTN Data
Data from the Chesapeake Bay Nontidal Network (NTN) up through water year 2020.
Data for nitrogen, phosphorus, and suspended-sediment loads and trends in the Chesapeake Bay Nontidal Network is updated every two years.
Most Recent RIM Data
Data from the Chesapeake Bay River Input Monitoring (RIM) stations up through water year 2023.
Data for nitrogen, phosphorus, and suspended-sediment loads and trends in the Chesapeake Bay River Input Monitoring stations is updated annually.
The Chesapeake Bay Nontidal Monitoring Program
Runoff in the Chesapeake Bay watershed carries pollutants, such as nutrients and sediments, to rivers and streams that drain to the Chesapeake Bay. The health of the Chesapeake Bay is therefore affected by changes in streamflow and the amount of pollution the water flowing to the Bay contains. The Chesapeake Bay Nontidal Monitoring Program measures the nutrient and sediment loads coming from the nontidal rivers within the Chesapeake Bay watershed. This data is used to estimate trends in sediment and nutrient loads, so that scientists and managers can assess the effectiveness of our efforts to reduce nutrient and sediment loads to the Bay.
The Chesapeake Bay Nontidal Network (NTN) is made up of 123 monitoring stations throughout the Chesapeake Bay watershed. Nine of these stations are part of the original monitoring network, which began collecting discharge data in 1985, and are referred to as River Input Monitoring (RIM) stations. RIM stations are generally located close to the tidal zone, where major rivers flow directly into the Chesapeake Bay. Roughly 78% of the Chesapeake Bay watershed area drains through one of the nine RIM sites. This is why nutrient and sediment loads from these nine stations are used to model the total loads to the Chesapeake Bay.
Most Recent Data Highlights
The nontidal network mapper is an interactive web page that summarizes the latest findings for nitrogen, phosphorus and suspended-sediment trends. Click the image below to explore the nontidal network mapper.
Loads
In 2020, estimated average annual streamflow entering the Chesapeake Bay was 77,800 cubic feet per second, which is only 2% below the long-term average of 79,404 cubic feet per second. The combined loads from the nine RIM stations were as follows:
- Total nitrogen: 156 million pounds, 48 million pounds less than the long-term average of 204 million pounds for 1985-2020.
- Total phosphorus: 8.41 million pounds, 3.66 million pounds less than the long-term average of 12.07 million pounds for 1985-2020.
- Suspended-sediment: 2.32 million tons, 1.8 million tons less than the long-term average of 4.12 million tons for 1985-2020.
Trends
Water quality trends as of 2020 are as follows:
- Total nitrogen: Thirty-four of 89 stations (38%) have improving trends. Thirty-seven of 89 stations (42%) have degrading trends. Eighteen of 89 stations (20%) show no statistical change. Click for interactive map.
- Total phosphorus: Thirty-one of 70 stations (44%) have improving trends. Sixteen of 70 stations (23%) have degrading trends. Twenty-three of 70 stations (33%) show no statistical change. Click for interactive map.
- Suspended sediment: Nine of 70 stations (17%) have improving trends. Twenty-three of 70 stations (44%) have degrading trends. Twenty of 70 stations (39%) show no statistical change. Click for interactive map.
Here you can find our most recent Nontidal Network (NTN) and River Input Monitoring (RIM) data releases, as well as links to our RIM station data feeds, our 2020 interactive results page, legacy data tables, and archived data releases.
Explore loads and trends data using interactive maps and graphs
Click below to access our NTN Loads and Trends 2020 Results page, then scroll down to find trend summaries, data querying tools, interactive loading graphs, and trend maps.
Data Release Archive
Looking for a previous version of our data? The most recent years of archived data releases can be found below. Older data releases can be found at the very bottom of this page.
Data Tables
Download full data tables (as CSV files) of NTN data through water year 2020 and RIM data through 2023.
Most Recent NTN Data (2020)
Most Recent RIM Data (2023)
Choptank River RIM Data Feed
Susquehanna River RIM Data Feed
Patuxent River RIM Data Feed
Potomac River RIM Data Feed
Rappahannock River RIM Data Feed
Pamunkey River RIM Data Feed
Mattaponi River RIM Data Feed
James River RIM Data Feed
Appomattox River RIM Data Feed
The Chesapeake Bay Nontidal Network is a cooperative effort between U.S. Geological Survey (USGS), the U.S. Environmental Protection Agency (USEPA), and agencies in the states of the Chesapeake watershed and the District of Columbia.
Environmental Protection Agency (EPA)
None of this work would be possible without funding from our partners at the Environmental Protection Agency.
Susquehanna River Basin Commission (SRBC)
The Susquehanna River Basin Commission is a federal-interstate coordinating agency which works to ensure future availability of flows to the Chesapeake Bay.
State Environmental Agencies
- Delaware Department of Natural Resources and Environmental Control
- District Department of Energy and Environment
- Maryland Department of Natural Resources
- New York State Department of Environmental Conservation
- Pennsylvania Department of Environmental Protection
- Virginia Department of Environmental Quality
- West Virginia Department of Environmental Protection
Access the most recent data gathered from the Chesapeake Bay Nontidal Monitoring Network, learn about the techniques used to collect this data, and read about the history of the Chesapeake Bay Nontidal Monitoring Program.
Nontidal Network (NTN) data refers to data from the 123 monitoring stations where nutrients and sediment are collected monthly and during storms.
River Input Monitoring (RIM) data refers to data from nine stations within the NTN network. This data is used to estimate the total amount of nutrient and sediment delivered to the Chesapeake Bay annually.
This page provides data access to our partners, cooperators, decision-makers, water quality managers, and scientists who need to access the latest data on nutrient and sediment loading to the Chesapeake Bay.
Most Recent NTN Data
Data from the Chesapeake Bay Nontidal Network (NTN) up through water year 2020.
Data for nitrogen, phosphorus, and suspended-sediment loads and trends in the Chesapeake Bay Nontidal Network is updated every two years.
Most Recent RIM Data
Data from the Chesapeake Bay River Input Monitoring (RIM) stations up through water year 2023.
Data for nitrogen, phosphorus, and suspended-sediment loads and trends in the Chesapeake Bay River Input Monitoring stations is updated annually.
The Chesapeake Bay Nontidal Monitoring Program
Runoff in the Chesapeake Bay watershed carries pollutants, such as nutrients and sediments, to rivers and streams that drain to the Chesapeake Bay. The health of the Chesapeake Bay is therefore affected by changes in streamflow and the amount of pollution the water flowing to the Bay contains. The Chesapeake Bay Nontidal Monitoring Program measures the nutrient and sediment loads coming from the nontidal rivers within the Chesapeake Bay watershed. This data is used to estimate trends in sediment and nutrient loads, so that scientists and managers can assess the effectiveness of our efforts to reduce nutrient and sediment loads to the Bay.
The Chesapeake Bay Nontidal Network (NTN) is made up of 123 monitoring stations throughout the Chesapeake Bay watershed. Nine of these stations are part of the original monitoring network, which began collecting discharge data in 1985, and are referred to as River Input Monitoring (RIM) stations. RIM stations are generally located close to the tidal zone, where major rivers flow directly into the Chesapeake Bay. Roughly 78% of the Chesapeake Bay watershed area drains through one of the nine RIM sites. This is why nutrient and sediment loads from these nine stations are used to model the total loads to the Chesapeake Bay.
Most Recent Data Highlights
The nontidal network mapper is an interactive web page that summarizes the latest findings for nitrogen, phosphorus and suspended-sediment trends. Click the image below to explore the nontidal network mapper.
Loads
In 2020, estimated average annual streamflow entering the Chesapeake Bay was 77,800 cubic feet per second, which is only 2% below the long-term average of 79,404 cubic feet per second. The combined loads from the nine RIM stations were as follows:
- Total nitrogen: 156 million pounds, 48 million pounds less than the long-term average of 204 million pounds for 1985-2020.
- Total phosphorus: 8.41 million pounds, 3.66 million pounds less than the long-term average of 12.07 million pounds for 1985-2020.
- Suspended-sediment: 2.32 million tons, 1.8 million tons less than the long-term average of 4.12 million tons for 1985-2020.
Trends
Water quality trends as of 2020 are as follows:
- Total nitrogen: Thirty-four of 89 stations (38%) have improving trends. Thirty-seven of 89 stations (42%) have degrading trends. Eighteen of 89 stations (20%) show no statistical change. Click for interactive map.
- Total phosphorus: Thirty-one of 70 stations (44%) have improving trends. Sixteen of 70 stations (23%) have degrading trends. Twenty-three of 70 stations (33%) show no statistical change. Click for interactive map.
- Suspended sediment: Nine of 70 stations (17%) have improving trends. Twenty-three of 70 stations (44%) have degrading trends. Twenty of 70 stations (39%) show no statistical change. Click for interactive map.
Here you can find our most recent Nontidal Network (NTN) and River Input Monitoring (RIM) data releases, as well as links to our RIM station data feeds, our 2020 interactive results page, legacy data tables, and archived data releases.
Explore loads and trends data using interactive maps and graphs
Click below to access our NTN Loads and Trends 2020 Results page, then scroll down to find trend summaries, data querying tools, interactive loading graphs, and trend maps.
Data Release Archive
Looking for a previous version of our data? The most recent years of archived data releases can be found below. Older data releases can be found at the very bottom of this page.
Data Tables
Download full data tables (as CSV files) of NTN data through water year 2020 and RIM data through 2023.
Most Recent NTN Data (2020)
Most Recent RIM Data (2023)
Choptank River RIM Data Feed
Susquehanna River RIM Data Feed
Patuxent River RIM Data Feed
Potomac River RIM Data Feed
Rappahannock River RIM Data Feed
Pamunkey River RIM Data Feed
Mattaponi River RIM Data Feed
James River RIM Data Feed
Appomattox River RIM Data Feed
The Chesapeake Bay Nontidal Network is a cooperative effort between U.S. Geological Survey (USGS), the U.S. Environmental Protection Agency (USEPA), and agencies in the states of the Chesapeake watershed and the District of Columbia.
Environmental Protection Agency (EPA)
None of this work would be possible without funding from our partners at the Environmental Protection Agency.
Susquehanna River Basin Commission (SRBC)
The Susquehanna River Basin Commission is a federal-interstate coordinating agency which works to ensure future availability of flows to the Chesapeake Bay.
State Environmental Agencies
- Delaware Department of Natural Resources and Environmental Control
- District Department of Energy and Environment
- Maryland Department of Natural Resources
- New York State Department of Environmental Conservation
- Pennsylvania Department of Environmental Protection
- Virginia Department of Environmental Quality
- West Virginia Department of Environmental Protection