ESTIMATION OF SNOW AND GLACIER-MELT CONTRIBUTION TO THE CHENAB RIVER,WESTERN HIMALAYA

The contribution of snow and glacier-melt runoff to Himalayan rivers i s significant and an estimation of the amount is necessary for the dev elopment, 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 19 92) the total water budget of the basin was assessed; rainfall data of 25 well-distributed stations were used to compute total rainfall inpu t 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 evaporati on from rain falling on the snow-covered area, and from the snow-cover ed area itself, is negligible. The snow-covered area in the basin was determined using satellite imagery. It is observed that, on average, a bout 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 sno w and glacier runoff contribution to the annual flow of the Chenab Riv er at Akhnoor is estimated to be about 49 percent.