CONFERENCE / REACT-2025

The Meenachil River Basin faces critical challenges in managing rainfall runoff, which often leads to adverse effects such as soil erosion and flooding. Effective management of runoff is essential for mitigating these issues and for improving the overall health of the watershed. Implementation of Best Management Practices (BMPs) can reduce runoff and improve water quality of the watershed. The primary objective of this study is to identify the most effective management practice to reduce runoff in the Meenachil river basin. Hydrological simulations of the watershed were performed using the SWAT model. To ensure accuracy sensitivity analysis, calibration, and validation of the model were conducted using SWAT-CUP software, employing the SUFI-2 (Sequential Uncertainty Fitting) technique. The model was calibrated using streamflow data of 13 years from 2001 to 2014 and validated another set of data of 3 years from 2015 to 2017.The Nash Sutcliffe Efficiency (NSE) value for calibration and validation (0.55 and 0.66) shows the models good performance. BMPs implemented in this study bench terrace, contour farming, contour bunding, filter strips. The annual runoff for the river basin was 93.074mm. This was reduced to 82.93, 82.93, 87.72, 92.57, 82.7, 82.7 and 87.25 respectively by bench terrace, contour bunds, contour farming, and filter strip, combination of bench terrace and filter strip, combination of contour bunding and filter strip, and combination of contour farming and filter strip respectively. The reduction efficiency was calculated and it was observed that combination of contour farming and bench terracing with filter strip achieved highest runoff reduction. These results revealed that the combined implementation of various BMPs significantly reduced runoff compared to individual BMPs. These finding underscores the effects of integrating multiple management practices. The study offers valuable insights for sustainable watershed management in the Meenachil River Basin.