Seasonal Rainfall and Stream-flow in the Ganges-Brahmaputra Basins of Bangladesh: Variability and Predictability

The flows of the Ganges and Brahmaputra in Bangladesh are highly seasonal, and heavily influenced by the monsoon rainfall. As a result the rivers in the region swell to brims and often overflow during the monsoon months whereas during the dry months (Nov. – May) the flows in the rivers reduce dramatically. The region, therefore, faces two major hazards: floods during the monsoon and scarcity of water during the dry season. These hazards are most pronounced in the downstream regions, particularly in Bangladesh, which is the lowest riparian of the Ganges. The objects of this paper are i) to study the hydro-meteorological variability and change for the greater Ganges and Brahmaputra regions, including the headwater regions and their role in stream flow in Bangladesh, and ii) to quantify the variability of key stream flow features of the seasonal hydrographs for Ganges and Brahmaputra Rivers, and iii) to explore the climatic factors influencing these hydrologic changes.