Spatial and temporal distribution of water availability in a small watershed to combat agricultural drought

Abstract

The most significant challenges the world currently facing is “Water Scarcity”. To reduce water scarcity in a locality, quantifying various components of water balance at a micro watershed scale is vital, either weekly or monthly. Therefore, a study was performed to quantify water accessibility in a small ungauged sub watershed namely Valanchery. In order to know the various hydrologic processes in the watershed, SWAT model was employed which is a physically based distributed watershed model. After initial simulation, the model was tested for its accuracy and the adjusted model was utilized to produce the required elements which are crucial in water management decision making. The obtained NSE and R² values indicate that the model was highly efficient at water balance components prediction both spatially and temporally. Using the calibrated model, the hydrologic processes of Valanchery watershed was simulated at micro watershed scale. The average annual discharge at the outlet was 3.44 m3/s. Surface runoff and groundwater were found to be the primary elements of water yield, while lateral flow accounted for only a small fraction, constituting just 2% of the annual rainfall. The study showed that analyzing the water balance and river flow at various reaches was highly effective in developing location-specific interventions to address water scarcity.