Snowmelt contributions to discharge of the Ganges

• Himalayan snowmelt contribution estimates to Ganges flow remain conjectural
• Estimates at seasonal and sub-basin scales are even more uncertain
• Using four models, annual snowmelt contribution to flow was estimated at 1% to 5%
• In spring, snowmelt contribution is high and reaches far into the Ganges plain

Himalayan headwaters supply large quantities of runoff derived from snowmelt and monsoon rainfall to the Ganges River. Actual snowmelt contribution to discharge in the Ganges remains conjectural under both present and future climatic conditions. As snowmelt is likely to be perturbed through climatic warming, four hydrological models, VIC, JULES, LPJmL and SWAT, appropriate for coupling with regional climate models, were used to provide a baseline estimate of snowmelt contribution to flow at seasonal and annual timescales. The models constrain estimates of snowmelt contributions to between 1% and 5% of overall basin runoff. Snowmelt is, however, significant in spring months, a period in which other sources of runoff are scarce.