Estimation of Runoff by SWAT Model in Noyyal River Basin

Accurate assessment of water balance components holds paramount importance for the sustainable management of water resources in river basins. This study specifically concentrates on the application of the Soil and Water Assessment Tool (SWAT) model to evaluate water balance elements within the Noyyal River basin, a tributary of the Kaveri River originating from the Vellingiri hills in Western Tamil Nadu grapples with escalating water stress brought about by both anthropogenic activities and climatic fluctuations.The methodology adopted encompasses the harmonious integration of diverse spatial and temporal datasets. These datasets are seamlessly incorporated within the confines of a Geographic Information System (GIS) framework. Through the process of watershed delineation 21 sub-basin was partitioned and which is further subdivided into 217 unique Hydrological Response Units (HRUs) are derived, each corresponding to a distinct hydrological reaction. The simulation employs 33 years of daily precipitation, coupled with minimum and maximum temperature records, enabling the continuous execution of the SWAT model for runoff prediction. The findings elucidate fluctuating runoff volumes over time, spanning from a minimum of 11.17 mm to a maximum of 610.32 mm. Notably, the annual average runoff stands at 206.7 mm, representing approximately 25.6% of the cumulative rainfall experienced within the Noyyal river basin.