ABSTRACT
Rivers originating from the Himalayan Region carry enormous amounts of sediment. Milliman and Syvitski (1992) stated that a third of the estimated contemporary global flux of about 18 Giga Tonnes per year (GT/yr) of fluvial suspended sediment is transported by the rivers of southern Asia. Of this total annual global flux, about 9% (1.6 GT/yr) is carried by five large rivers which originate in the Himalaya, the Brahmaputra, Ganga, Indus, Irrawaddy and Mekong. In general the sediment fluxes of these rivers are substantially higher than those of rivers draining other mountainous regions of the world. If dams and barrages had not been constructed, the three principal rivers of the Indian Sub-continent would annually deliver a combined 1.2 GT/yr (7% of the total global flux) to the coast (Milliman and Meade, 1983; Milliman and Syvitski, 1992). An earlier estimate by Meybeck (1976) suggested that the Brahmaputra, Ganga and Indus transport an aggregated pre-dam flux of 1.6 GT/yr.
