Application of SWAT model for simulation of runoff in micro watersheds of lower Himalayan region of India

The physically based Soil and Water Assessment Tool (SWAT) was applied to two micro watersheds of lower Himalayan region of India. Areas of the micro-watersheds are 21 ha (watershed) and 70.45 ha (W3B watershed), respectively, with the land use of range brush and mixed forest. Nine years and twelve years monthly rainfall data, respectively were used to simulate the hydrological behaviour of these watersheds. In order to establish the effectiveness of model to simulate hydrological responses to climatic variations, the simulated values were subjected to rigorous calibration with observed runoff data on a monthly time scale. The model was calibrated for the period 1973–1978 and 1971 to 1980, respectively for monsoon months and validated for the period 1979–1981 and 1982–1984, respectively for micro watersheds, Choe and W3F. Both, calibration and validation outputs were found to be reasonably acceptable with Nash Sutcliffe efficiency (NSE) as 66.4 and 80.2% for calibration period for Choe and W3B watersheds, respectively. NSE values for validation for Choe and W3B watersheds were also found to be 73.3 and 72.1%, respectively suggesting better parameterization and simulation performance. Since the database on SWAT model's potential in simulation performance on micro watershed scale is scanty, this paper was successful in showcasing the potential of SWAT in simulating the runoff of micro-watersheds of lower Himalayan regions.