Evaluation of the Influence of Land Use and Climate Changes in Runoff Simulation Using Semi-Distributed Hydrological Model

Water resources must be managed effectively to meet current and future demands, ensure sustainability, and meet the needs of a growing population. Identification of the characteristics of resources in the basin, such as the land use land cover (LULC), climatic parameters, and runoff, makes it possible to manage water resources for a long time. In this study, using the hydrological model, Soil and Water Assessment Tool (SWAT), a separation strategy, was implemented in the Meenachil River basin in the Kottayam district of Kerala to differentiate the effects of change in climate and LULC on runoff. The calibration and validation of the SWAT model were facilitated by runoff data available at gauging station Kidangoor within the study area from 1987 to 2010 for the calibration (1987–2004) and validation periods (2005–2010), respectively. Four distinct scenarios were examined to determine the relative impact of LULC and climate on runoff. The findings showed that the variation in streamflow over the study area is significantly affected by climate change (84.86%), with land use having a 15.13% influence.