Water is the most vital element and crucial for the survival of all living organisms. The environment, economic growth and development are highly influenced by water. Spatial and seasonal availability of surface and groundwater is highly responsive to the monsoon climate and physiography of the country and upstream withdrawal for consumptive and non-consumptive uses. Our country is the lower riparian of three major river systems, the Ganges-Padma, the Brahmaputra-Jamuna and the Meghna (GBM). The problem is that we have too much water during the monsoon and too little in the dry season.