Water Balance Study for a Basin Integrating Remote Sensing Data and GIS

Water balance of a basin involves estimation of input precipitation, runoff, infiltration and evapotranspiration (ET). Although ET may have large variations over a big basin, it is commonly estimated using a few point measurements and this makes the estimation error prone. Satellite based remote sensing data provides few parameters for estimation of energy fluxes, at the land surface and atmosphere interaction in a distributed manner using the meteorological parameters. These parameters through surface energy balance equation have been used for the estimation of ET in this study. Various spatially distributed variables required for ET estimation; viz. NDVI, surface albedo, surface temperature etc. have been derived using remote sensing and ancillary data for Tapi basin located in western India. Beside this field data such as rainfall, air temperature, relative humidity, sunshine hours etc. have been used. For computation of runoff, Soil Conservation Services (SCS) approach has been considered. Tapi basin up to Ukai dam has been selected as the study area. Satellite data from National Oceanic and Atmospheric Administration (NOAA), Polar Orbiting Environmental Satellite, which carries the Advanced Very High Resolution Radiometer (AVHRR), have been used for preparation of various maps required for runoff and ET analysis. The results of runoff and ET have been compared with observed data for 2 years, 2002–2003 and the results have been found in good agreement with observed data.