This dataset contains estimates of the yearly sum of nitrogen atmospheric deposition of inorganic nitrogen in selected Chesapeake Bay watersheds from 1985-2012. Data for 1985-2012 were downloaded from the National Atmospheric Deposition Program.

Reactive nitrogen is transported from the atmosphere to the landscape as wet and dry deposition that contributes to annual nitrogen loads to the Chesapeake Bay. Estimates of atmospheric inorganic nitrogen deposition to the Chesapeake Bay watershed during 1950 to 2050 are presented, and are based on field measurements, model simulations, statistical relations, and surrogate constituents used for estimates. Wet atmospheric nitrogen deposition has generally been quantified from weekly precipitation sample collections, whereas dry atmospheric nitrogen deposition has been simulated by a model at an hourly time step.

Reactive nitrogen is transported from the atmosphere to the landscape as wet and dry deposition that contributes to annual nitrogen loads to the Chesapeake Bay. Estimates of atmospheric inorganic nitrogen deposition to the Chesapeake Bay watershed during 1950 to 2050 are presented, and are based on field measurements, model simulations, statistical relations, and surrogate constituents used for estimates. Wet atmospheric nitrogen deposition has generally been quantified from weekly precipitation sample collections, whereas dry atmospheric nitrogen deposition has been simulated by a model at an hourly time step.

USGS generated Estimates of atmospheric inorganic nitrogen deposition to the Chesapeake Bay watershed, 1950-2050. This dataset is associated with the following publication: Burns, D., G. Bhatt, L. Linker, J. Bash, P. Capel, and G. Shenk. Atmospheric Nitrogen Deposition in the Chesapeake Bay Watershed: A History of Change. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, USA, 251(15): 118277, (2021).

USGS generated Estimates of atmospheric inorganic nitrogen deposition to the Chesapeake Bay watershed, 1950-2050. This dataset is associated with the following publication: Burns, D., G. Bhatt, L. Linker, J. Bash, P. Capel, and G. Shenk. Atmospheric Nitrogen Deposition in the Chesapeake Bay Watershed: A History of Change. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, USA, 251(15): 118277, (2021).

This USGS data release contains datasets, metadata, and figures associated with estimating nitrate loads and yields from groundwater to streams in the Chesapeake Bay watershed based on land use and geology. There are three shapefiles with associated metadata and figures representing the shapefiles: • Catchments_GWcontribN.shp: NHDPlus catchment estimates of groundwater contribution of nitrate to streams in the Chesapeake Bay watershed • HUC12_GWcontribN.shp: HUC 12 estimates of groundwater contribution of nitrate to streams in the Chesapeake Bay watershed • Sites_GWcontribN.shp: Sites with baseflow measurements for nitrate plus nitrite within the Chesapeake Bay watershed These data support the following publication: • Terziotti, Silvia, Capel, P.D., Tesoriero, A.J., Hopple, J.A., and Kronholm, S.C., 2017, Estimates of nitrate loads and yields from groundwater to streams in the Chesapeake Bay watershed based on land use and geology: U.S. Geological Survey Scientific Investigations Report 2017-5160, 20 p., https://doi.org/10.3133/sir20175160.

This USGS data release contains datasets, metadata, and figures associated with estimating nitrate loads and yields from groundwater to streams in the Chesapeake Bay watershed based on land use and geology. There are three shapefiles with associated metadata and figures representing the shapefiles: • Catchments_GWcontribN.shp: NHDPlus catchment estimates of groundwater contribution of nitrate to streams in the Chesapeake Bay watershed • HUC12_GWcontribN.shp: HUC 12 estimates of groundwater contribution of nitrate to streams in the Chesapeake Bay watershed • Sites_GWcontribN.shp: Sites with baseflow measurements for nitrate plus nitrite within the Chesapeake Bay watershed These data support the following publication: • Terziotti, Silvia, Capel, P.D., Tesoriero, A.J., Hopple, J.A., and Kronholm, S.C., 2017, Estimates of nitrate loads and yields from groundwater to streams in the Chesapeake Bay watershed based on land use and geology: U.S. Geological Survey Scientific Investigations Report 2017-5160, 20 p., https://doi.org/10.3133/sir20175160.

This U.S. Geological Survey data release contains datasets that combine past data with future projections of nitrogen sources and nitrogen export to the Chesapeake Bay watershed for the years 1950-2050. To help understand the effect of human and environmental changes over this time period, data for nitrogen sources from wastewater, agricultural fertilizer and manure, and atmospheric deposition are combined with datasets of population and land use. These datasets were used in conjunction with a previously calibrated SPAtially Referenced Regression On Watershed attributes (SPARROW) modeling tool to estimate the mean annual loads of total nitrogen to the Chesapeake Bay and nontidal stream reaches in the watershed at a decadal timestep from 1950-2050. SPARROW model output of incremental and total loads for each reach in the Chesapeake Bay watershed are reported in this data release.

This U.S. Geological Survey data release contains datasets that combine past data with future projections of nitrogen sources and nitrogen export to the Chesapeake Bay watershed for the years 1950-2050. To help understand the effect of human and environmental changes over this time period, data for nitrogen sources from wastewater, agricultural fertilizer and manure, and atmospheric deposition are combined with datasets of population and land use. These datasets were used in conjunction with a previously calibrated SPAtially Referenced Regression On Watershed attributes (SPARROW) modeling tool to estimate the mean annual loads of total nitrogen to the Chesapeake Bay and nontidal stream reaches in the watershed at a decadal timestep from 1950-2050. SPARROW model output of incremental and total loads for each reach in the Chesapeake Bay watershed are reported in this data release.

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).