Assessment of surface water availability in Arjuna river basin using ArcSWAT

Abstract

The present investigation was to study water availability in Arjuna River basin of Ratnagiri District of the Maharashtra state utilizing the ArcSWAT model, an advanced tool for hydrological simulation. The study encompasses the collection and analysis of extensive historical meteorological and hydrological data, aiming to understand the dynamics of surface water availability across different seasons and from 1996-2016 with the model undergoing rigorous calibration and validation processes to ensure accuracy. Employing the ArcSWAT model for hydrological simulation, the research aims to understand the intricate dynamics of water availability and its distribution across the basin, essential for strategic planning and sustainable management. The entire basin was divided into 8 subbasins, each further subdivided into 294 hydrological resource units (HRU) based on land use, land cover and topography. ArcSWAT underwent calibration and validation, including a 3-year model warm-up period. Output data covered a span of 21 years from 1996 to 2016. Calibration occurred from 1996 to 2003, followed by validation from 2007 to 2012. The ArcSWAT model demonstrated statistically promising results in hydrological simulations, with R² values of 0.78 for calibration and 0.67 for validation, indicating satisfactory performance in replicating monthly runoff values. NSE values of 0.75 for calibration and 0.65 for validation, as well as RMSE values of 0.50 for calibration and 0.60 for validation, further confirmed the model's effectiveness.