Snow Melt Runoff Status in Part of Ganga Basin

Abstract

The temporal and permanent snow cover along with glaciers form an important part of Himalayan ecosystem and hydrological cycle. The Ganga River with its origin from glaciers of Gangotri and Alakhnanda valley has significant water contributions from melt waters of these glaciers and snowmelt runoff. The percent contribution of snowmelt and glacier melt water is highest in headwater reaches of Ganga basin. The present chapter has focused on mapping of these snow bound areas using remote sensing and integrating the Snow Cover Area (SCA) with hydrometeorological data in temperature index based snowmelt runoff models. The Bhagirathi river basin upto Uttarkashi and Alakhnanda river basin upto Joshimath are taken for this study. Landsat, Resourcesat-1 and MODIS satellites were used for SCA estimation. WINSRM has been used for snowmelt runoff simulation. The discharge data from central water commission was used to calibrate and validate the simulated snowmelt runoff. The Coefficient of determination, R² for Bhagirathi river basin comes in range of 0.76–0.84 for 2002–2007 time periods, similarly for Alakhnanda river it comes about 0.87 and 0.90 for year 2000 and 2008. Overall this study shows that snowmelt runoff can be estimated using temperature index approach in this area and well distributed network of hydrometeorological stations will give better accuracy for snowmelt runoff models.