Simulating Surface Runoff Response to Land Use Change Using ArcSWAT in Jonk Subbasin

Abstract

Land use and land cover (LULC) changes are widely recognized as key drivers of hydrological variability, particularly in tropical regions where observational data are often limited. The present study evaluates the influence of long-term LULC transformations on surface runoff dynamics in the Jonk sub-basin of the Mahanadi River basin using the Arc Soil and Water Assessment Tool (ArcSWAT). Multi-temporal spatial datasets, including satellite-derived LULC maps, soil information, and a Digital Elevation Model (DEM), were integrated with hydro-meteorological data for the period 1991–2021. The watershed was delineated into 11 sub-watersheds and further discretized into 277 Hydrological Response Units (HRUs) to represent spatial heterogeneity. Model calibration (1993–2010) and validation (2011–2021) showed strong performance with R² = 0.83 and NSE = 0.82, indicating reliable simulation of streamflow. Analysis of LULC changes revealed a significant expansion of agricultural and built-up areas, accompanied by a decline in forest cover. These changes resulted in increased Curve Number values and reduced infiltration capacity, ultimately leading to a 9–11% increase in mean annual surface runoff. The study highlights the critical role of anthropogenic land transformations in altering watershed hydrology and emphasizes the need for sustainable land management strategies in data-scarce regions.