Development of a SWAT Model to Investigate the Impact of Hydroclimate and Land Uses on Water Quantity and Quality in the ‘Dhurang Khal’ River, Bangladesh

Abstract

The surface-overflow runoff and nitrogen load of the designated watershed of Dhurang Khal River were estimated by developing a hydrologic model in ArcSWAT platform. ArcGIS-ArcSWAT was used to process the spatiotemporal data. MS Excel was used to compare observed and simulated data from software and to generate graphs. The curve number was changed manually to accomplish manual calibration. By comparing 2020 simulated surface overflow data with 2020 observed surface overflow data, good calibration (R2 = 0.66) was discovered. The Validation (R2 = 0.61) was accomplished by comparing observed data for 2021-2022 to model generated data for 2021-2022. A comparison graphic was developed by comparing data from 2021 observed surface overflow to data from 2052 simulated surface overflow. We used a vegetative strip as a natural way to minimize nitrogen load in 2021. We were able to lower nitrogen load by about 20% after installing the vegetative filter strip during the peak agricultural month of August. The projection of future surface overflow data also suggested that after 30 years, there will be a significant decline in surface overflow runoff during growing season, while an increase was observed in non-growing season.