Evaluation of the SWAT Model for Analysing the Water Balance Components for the Upper Sabarmati Basin

Abstract

Evaluation of various components of hydrologic cycle is necessary for planning and management of a river basin/watershed. The present study evaluated the water balance components in parts of upper Sabarmati basin (6211.56 km2) of central India using the soil and water assessment tool (SWAT) hydrologic model. The river basin was delineated to 31 sub-basins encompassing 116 hydrologic response units (HRUs). Monthly calibration (1992–1999) and validation (2000–2005) of the SWAT model were carried out using observed discharge data at Derol Bridge, Gujarat, India. Trend analysis results over the period of 1992–2005 for run-off and evapotranspiration shows an insignificant decreasing trend, along with decrease in precipitation with a magnitude of 21 mm/year, The model simulation results indicated a reduction in surface run-off (323.49–232.14 mm) and potential evapotranspiration(1935.71–1875.71 mm) between years 1992 and 2005. The present study also revealed a considerable decrease in water yield (493.2–317.6 mm) for same duration.