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

Abstract

The study aims to investigate the impact of hydro climate and land uses on water quantity and quality in the watershed of Karatoa River in Bangladesh by developing a hydrologic and water quality model in ArcSWAT. We used ArcGIS and ArcSWAT modeling software to obtain information on the nitrogen load and flow and projected surface overflow runoff for the project's chosen watershed area. ArcGIS - ArcSWAT was used to process spatiotemporal data. Microsoft - MS Excel was used to compare actual data with simulated data from software and display various graphs. By altering the curve number and slope number, manual calibration (R2 value = 0.73) was performed using observed discharge data during 2019-2020. Comparing observed data for 2021 with model simulated data for 2021, the validation (R2 = 0.54) was performed. Using data from 2053 simulations of surface overflow, a comparison chart was made. For the year 2022, we designed a vegetative filter strip as a natural way to reduce (28%) the nitrogen load in the peak month (January). The projection of future surface overflow data also indicated that, after 30 years, there will be a considerable reduction in surface overflow runoff.