The Influence of Land Use and Land Cover Transitions on Hydrology in a Tropical River Basin of Southwest India

The Kali River basin in Karnataka, India, is a vital hydropower resource, crucial to the state's economy. Understanding the region's hydrological processes and the factors influencing water availability is essential, with land use and land cover (LULC) change being a significant driver of these impacts. This study focuses on detecting LULC changes in the Kali River basin and assessing their effects on hydrological processes within the Supa Dam catchment area. Using satellite images from 1992, 2002, 2013, and 2022 and the ERDAS imagine tool, LULC classification was done with a supervised classification algorithm. The analysis revealed that from 1992 to 2022, the basin experienced a 5.97% decline in dense forest and a 5.64% decrease in open forest cover, while agricultural land expanded by 7.03%, and tree plantations increased by 1.49%. Water bodies increased by 1.44%, built-up areas and barren land rose by 0.97% and 0.76%, respectively, with grassland remaining stable. The impact of these LULC changes on hydrological processes was evaluated using the Soil and Water Assessment Tool (SWAT) model. Between 1992 and 2013, the model, which showed a surface flow increase of 212.83 mm, a water yield decrease of 46.10 mm, an increase in lateral flow by 37.95 mm, and a decrease in groundwater flow by 180.90 mm, with R2 and NSE values exceeding 0.60 for both calibration and validation, demonstrates satisfactory model performance. These findings underscore the importance of understanding LULC change impacts on streamflow to guide effective land management strategies and mitigate adverse effects on the watershed's hydrology.