Modeling the impact of future Land Use Land Cover changes on surface runoff in the Periyar River Basin, India

In modern times, anthropogenic induced urbanization has become a major urban environmental and natural concern, particularly in most developing countries. In India, rapid urbanization, especially in coastal regions, has had a significant impact on runoff resulting in more frequent floods and greater havoc in many coastal cities. Hence, prior knowledge on impacts of urbanization on runoff is critical for urban planners and policymakers to control flood associated hazards. The objective of the present study is to assess the impact of Land Use Land Cover Changes (LULC) on runoff in the Periyar River Basin (PRB) in rapidly urbanizing Indian Coastal District, Ernakulum under present and future scenarios with the aid of Soil Water and Assessment Tool (SWAT). The model performance was evaluated using the Sequential Uncertainty Fitting algorithm (SUFI-2) using observed streamflow data; results demonstrate the satisfactory performance of the model. The Cellular Automata Markov Chain model was used to predict future LULC maps for 2045, 2073, and 2100. The land use maps for all three scenarios were then used in the calibrated SWAT model to project future runoff. The results illustrate that there is a substantial increase in runoff under projected LULC scenarios. The surface runoff volume was noticed to increase in the future by 48%, 61%, and 65% under future LULC scenarios of 2045, 2073, and 2100 respectively. The outcomes of the study provide insight about LULC change impacts on runoff in PRB, and has immediate implications for land use conversion planning.