The dataset contains estimates for total nitrogen and total phosphorus loads from point sources, combined sewer overflows, wastewater treatment plants that discharge to surface water for selected Chesapeake Bay watersheds. For source information, please refer to the process steps in this metadata report.

This dataset contains estimates of the yearly sum of total nitrogen and total phosphorus (hereafter referred to as nitrogen and phosphorus) inputs from fertilizer applications and from manure applications in selected Chesapeake Bay watersheds from 1985 through 2012.

This dataset contains estimates of the yearly sum of total nitrogen and total phosphorus (hereafter referred to as nitrogen and phosphorus) inputs from fertilizer applications and from manure applications in selected Chesapeake Bay watersheds from 1985 through 2012.

Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in major rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay River Input Monitoring Network (RIM) stations for the period 1985 through 2017. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). Yields (represents the mass of constituent transported from a unit area of a given watershed) are used to compare the export loads from one basin to another. Yield results are obtained by dividing the annual load (pounds) of a given constituent by the respective watershed area (acres) from which the constituent was transported. Yield results presented represent the average annual per-acre loads of nitrogen, phosphorus, and suspended sediment exported from each of the Chesapeake Bay River Input Monitoring stations for two possible time periods: 2008-2017 (10 year average yield) and 2013-2017 (5 year average yield).

Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in major rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay River Input Monitoring Network (RIM) stations for the period 1985 through 2018. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). Yields (represents the mass of constituent transported from a unit area of a given watershed) are used to compare the export loads from one basin to another. Yield results are obtained by dividing the annual load (pounds) of a given constituent by the respective watershed area (acres) from which the constituent was transported. Yield results presented represent the average annual per-acre loads of nitrogen, phosphorus, and suspended sediment exported from each of the Chesapeake Bay River Input Monitoring stations for two possible time periods: 2009-2018 (10 year average yield) and 2014-2018 (5 year average yield).

Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in major rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay River Input Monitoring Network (RIM) stations for the period 1985 through 2018. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). Yields (represents the mass of constituent transported from a unit area of a given watershed) are used to compare the export loads from one basin to another. Yield results are obtained by dividing the annual load (pounds) of a given constituent by the respective watershed area (acres) from which the constituent was transported. Yield results presented represent the average annual per-acre loads of nitrogen, phosphorus, and suspended sediment exported from each of the Chesapeake Bay River Input Monitoring stations for two possible time periods: 2009-2018 (10 year average yield) and 2014-2018 (5 year average yield).

Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in major rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay River Input Monitoring Network (RIM) stations for the period 1985 through 2019. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). Yields (represents the mass of constituent transported from a unit area of a given watershed) are used to compare the export loads from one basin to another. Yield results are obtained by dividing the annual load (pounds) of a given constituent by the respective watershed area (acres) from which the constituent was transported. Yield results presented represent the average annual per-acre loads of nitrogen, phosphorus, and suspended sediment exported from each of the Chesapeake Bay River Input Monitoring stations for two possible time periods: 2010-2019 (10 year average yield) and 2015-2019 (5 year average yield).

Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in major rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay River Input Monitoring Network (RIM) stations for the period 1985 through 2019. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). Yields (represents the mass of constituent transported from a unit area of a given watershed) are used to compare the export loads from one basin to another. Yield results are obtained by dividing the annual load (pounds) of a given constituent by the respective watershed area (acres) from which the constituent was transported. Yield results presented represent the average annual per-acre loads of nitrogen, phosphorus, and suspended sediment exported from each of the Chesapeake Bay River Input Monitoring stations for two possible time periods: 2010-2019 (10 year average yield) and 2015-2019 (5 year average yield).

To estimate changes in nitrogen, phosphorus, and sediment loads from technologies and management practices (TMPs), the Chesapeake Bay Program Partnership's CAST model was used to run scenarios with and without TMPs for years between 1985 and 2020 for the Chesapeake Bay watershed. Scenarios were run using the native model segmentation of land-river segments and downscaled to the National Hydrography Dataset (NHD) plus version 2 catchments. The land-river segment loads were disaggregated to the National Hydrography Dataset Plus, Version 2.0 using methods described in "CAST Data Input Disaggregation from County and Land-River Segment Scale to National Hydrography Dataset Plus". The estimated total nitrogen (TN), total phosphorus (TP), and total suspended solids (TSS) for each scenario are in the data and are organized by the NHDPlus v2 catchments. There are 50,336,640 rows of data. The data include the amount of each contaminant that is delivered to the edge of a small stream. These data allow researchers to assess the overall impact of TMPs over time for various land uses. The data file is named ProgNA_RA_C1920220313. The file is uploaded as a zipped file and as a .txt file. The files are identical and the data user can choose the format that is best for them. The file name refers to the progress (prog) scenarios for each year with TMPs and the no action (NA) or no TMP scenarios with regulation air (RA) in CAST version 19 (C19) and the data were created on 3/13/2022.

To estimate changes in nitrogen, phosphorus, and sediment loads from technologies and management practices (TMPs), the Chesapeake Bay Program Partnership's CAST model was used to run scenarios with and without TMPs for years between 1985 and 2020 for the Chesapeake Bay watershed. Scenarios were run using the native model segmentation of land-river segments and downscaled to the National Hydrography Dataset (NHD) plus version 2 catchments. The land-river segment loads were disaggregated to the National Hydrography Dataset Plus, Version 2.0 using methods described in "CAST Data Input Disaggregation from County and Land-River Segment Scale to National Hydrography Dataset Plus". The estimated total nitrogen (TN), total phosphorus (TP), and total suspended solids (TSS) for each scenario are in the data and are organized by the NHDPlus v2 catchments. There are 50,336,640 rows of data. The data include the amount of each contaminant that is delivered to the edge of a small stream. These data allow researchers to assess the overall impact of TMPs over time for various land uses. The data file is named ProgNA_RA_C1920220313. The file is uploaded as a zipped file and as a .txt file. The files are identical and the data user can choose the format that is best for them. The file name refers to the progress (prog) scenarios for each year with TMPs and the no action (NA) or no TMP scenarios with regulation air (RA) in CAST version 19 (C19) and the data were created on 3/13/2022.