Glacier plays an important role in streamflow regimes of mountainous drainage basins and is a vital source of runoff in the summer months (Kaser et al., 2010). Even a basin where glacier fraction is less than 0.5% can provide a significant contribution from glacial meltwater to summer runoff. Glaciers have generally experienced retreat and thinning since the beginning of the 20th century (IPCC, 2007). The continued glacier shrinkage due to the ongoing effects of global climate change has raised concerns about the role of the glaciers as a source of freshwater, because these impacts affect not only the local catchment area but also adjacent lowlands far beyond the limits of the glacierized mountain ranges. Hence, there is a need for analyzing the long-term trend in glacier runoff variability and its impact on river runoff for regional water supplies.