| Title: | SWAT modeling of non-point source pollution in depression-dominated basins under varying hydroclimatic conditions |
| Authors: | Nasab, M.T., K. Grimm, M.H. Bazrkar, L. Zeng, A. Shabani, X. Zhang and X. Chu |
| Year: | 2018 |
| Journal: | International Journal of Environmental Research and Public Health |
| Volume (Issue): | 15(11) |
| Pages: | |
| Article ID: | 2492 |
| DOI: | 10.3390/ijerph15112492 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | hydrologic and pollutant |
| Primary Application Category: | depressional (pothole, wetland or pond) effects and/or processes |
| Secondary Application Category: | nitrogen cycling/loss and transport |
| Watershed Description: | 103,600 km^2 portion of the Red River of the North, that drains parts of northeast North Dakota, northwest Minnesota and northeast South Dakota in the north central U.S. |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | Pothole depressional areas were represented with wetlands in this study. |
| Abstract: | Non-point source (NPS) pollution from agricultural lands is the leading cause of various
water quality problems across the United States. Particularly, surface depressions often alter
the releasing patterns of NPS pollutants into the environment. However, most commonly-used
hydrologic models may not be applicable to such depression-dominated regions. The objective of this
study is to improve water quantity/quality modeling and its calibration for depression-dominated
basins under wet and dry hydroclimatic conditions. Specifically, the Soil and Water Assessment
Tool (SWAT) was applied for hydrologic and water quality modeling in the Red River of the North
Basin (RRB). Surface depressions across the RRB were incorporated into the model by employing
a surface delineation method and the impacts of depressions were evaluated for two modeling
scenarios, MS1 (basic scenario) and MS2 (depression-oriented scenario). Moreover, a traditional
calibration scheme (CS1) was compared to a wet-dry calibration scheme (CS2) that accounted
for the effects of hydroclimatic variations on hydrologic and water quality modeling. Results
indicated that the surface runoff simulation and the associated water quality modeling were
improved when topographic characteristics of depressions were incorporated into the model (MS2).
The Nash–Sutcliffe efficiency (NSE) coefficient indicated an average increase of 30.4% and 19.6% from
CS1 to CS2 for the calibration and validation periods, respectively. Additionally, the CS2 provided
acceptable simulations of water quality, with the NSE values of 0.50 and 0.74 for calibration and
validation periods, respectively. These results highlight the enhanced capability of the proposed
approach for simulating water quantity and quality for depression-dominated basins under the
influence of varying hydroclimatic conditions. |
| Language: | English |
| Keywords: | SWAT; hydrologic modeling; water quality modeling; depressions; watershed |