Development of a SWAT Model to Investigate the Impact of Hydroclimate and Land Uses on Water Quantity and Quality in the 'Atrai' River, Bangladesh

Abstract

A project on the Atrai River was studied to calculate the surface-overflow runoff and nitrogen load of the selected watershed area. To get the data on present and future surface-overflow load and nitrogen load of the selected watershed area of the project, we used ArcGIS and ArcSWAT modeling software. The spatiotemporal data were processed in ArcGIS-ArcSWAT. The comparison of observed and simulated data from software and graph plotting was done by using MS Excel. Manual calibration was performed by changing the curve number. Good calibration (R2 = 0.654) was found by comparing 2020 simulated surface overflow data with 2020 observed surface overflow data. The validation (R2 = 0.67) was done by comparing observed data for 2021- 2022 and model simulated data for 2021-2022. A comparison chart was created comparing 2021 observed surface overflow with 2052 simulated surface overflow data. We applied a vegetative strip as a nature-based solution to reduce nitrogen load for the year 2021. After applying the vegetative filter strip, we were able to reduce nitrogen load by almost 25% in the peak farming month of June. The forecast of future surface overflow data also showed that in the future there will be a drastic decrease in surface overflow load after 30 years.