These data are associated with the manuscript entitled: “Watershed Scale Nitrate-N Abatement of Instream Wetlands: An Appraisal Using the Soil and Water Assessment Tool” (doi: 10.13031/aea.13736). The study elucidated the watershed-scale nitrate-N abatement potential of constructed instream wetlands (ISWs). Hence, the Soil and Water Assessment Tool (SWAT) was used to model nitrate-N export in a highly agricultural watershed located in the Coastal Plain of North Carolina. SWAT was first calibrated and validated for streamflow and for nitrate-N export using data collected from the inlet and outlet of an experimental instream wetland. The validated SWAT model was used to simulate a decade of nitrate-N export under two scenarios: 1) watershed with ISWs implemented; and 2) watershed without ISWs. The results of the case study indicated that a watershed-wide implementation of ISWs is likely to curtail annual nitrate-N export by 49%. The study also evaluated cases where ISWs are implemented in selected percentage of sub-basins across the watershed. The outcomes show higher increments of nitrate-N curtailment when ISWs are implemented in the first top agricultural sub-basins. Hence, implementation of ISWs on selected sub-basins can mitigate nitrate-N from non-point sources and enhance water quality in the watershed’s stream network. The dataset provided here includes input weather data used for SWAT, flow, and nitrate-N observation data used to calibrate and validate SWAT, simulated data associated with figures, and tables reported in the manuscript.  

Measurements of streamflow and nitrate-N loading were continuously collected at the inlet and outlet of an experimental instream wetland located in the Herrings Marsh Run watershed. Additional data were retrieved from the United States Geological Survey and the National Oceanic and Atmospheric Administration databases.