The study estimates the average contribution of snow and glacier melt runoff in the annual flow of Satluj river at Bhakra dam. This study is restricted to the Indian part of Satluj basin. A water balance approach was used to determine the average snow and glacier contribution to the annual flows.
The total water budget of the basin was computed for ten years (Oct 1986 to Sept 1996). Rainfall data of ten stations were used to compute total rainfall input to the basin over the water budget period. The total volume of flow for the same period is computed using the discharge data at Bhakra reservoir.
Evapotranspiration losses from the basin are taken into account only from the snow free area as the evaporation losses from the rain falling on the snow covered area can be taken to be negligible. The snow covered area in the basin has been determined using satellite data.
It is observed that on an average about 65 % area of the basin is covered with snow in the month of March and April, which reduces to about 20 % in the month of September and October. The average snow and glacier runoff contribution in the annual flow of Satluj river at Bhakra is estimated to be about 61 %. Markedly, most of the streamflow into the Bhakra reservoir is generated from snow and glacier melts. Even during the monsoon period significant amounts of snow and glacier melt are generated from the high altitude regions in the Satluj basin.
The contribution of snow and glacier melt runoff in all the Himalayan rivers originating from Himalayas is very significant. The estimation of snow and glacier melt runoff is required for water resources development of the region.
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