Streamflow assessment of the lower Godavari river basin using the SWAT model
摘要
Reliable streamflow assessment is essential for sustainable water resource management, particularly in large tropical basins affected by data scarcity, climatic variability, and land-use change. This study evaluates long-term streamflow dynamics in the Lower Godavari River Basin using the Soil and Water Assessment Tool (SWAT) within the ArcSWAT framework. Spatially distributed meteorological, land-use, topographic, and soil datasets were integrated to simulate hydrological processes over a 36-year period. Model calibration (1984–2014) and validation (2015–2020) were performed using the SUFI-2 algorithm in SWAT-CUP, with performance assessed through NSE, R², and RSR statistics. Sensitivity analysis identified the runoff curve number (CN2) and groundwater delay (GW_DELAY) as the most influential parameters controlling streamflow response. The model achieved satisfactory performance, yielding NSE values of 0.86 and 0.84 and R² values of 0.89 and 0.85 for calibration and validation, respectively. Results indicate that SWAT effectively captures the temporal variability and hydrological behaviour of this monsoon-driven, data-scarce basin. The study provides a robust multi-decadal assessment of catchment response and hydrological variability, offering valuable insights for basin-scale water management, climate-resilient planning, and flood risk mitigation in similar tropical and semi-humid river systems.