Estimation of snow and glacier-melt contribution to the Chenab River, Western Himalaya

The contribution of snow and glacier-melt runoff to Himalayan rivers is significant and an estimation of the amount is necessary for the development, planning, and management of water resources. In this study, the average contribution of snow and glacier-melt runoff in the annual streamflow of the Chenab River at Akhnoor was estimated using a water balance approach. For a period of 10 years (October 1982-September 1992) the total water budget of the basin was assessed; rainfall data of 25 well-distributed stations were used to compute total rainfall input to the basin, and total volume of flow was computed using discharge data at the Akhnoor gauging site. Evapotranspiration losses only from the snow-free area were taken into account, considering that evaporation from rain falling on the snow-covered area, and from the snow-covered area itself, is negligible. The snow-covered area in the basin was determined using satellite imagery. It is observed that, on average, about 70% of the area of the basin is covered with snow in March/April and this is reduced to about 24% in September/October. The average snow and glacier runoff contribution to the annual flow of the Chenab River at Akhnoor is estimated to be about 49 percent.