Food security and economic livelihood of millions of people in Asia and Africa shall continue to depend upon the flows in the major rivers. Variability of water and other resources in time and space is the major natural impediment for sustainable agriculture, food production and development at large. The extremes of variability - floods and droughts - are the primary "agents" of destruction, severe crop damage and loss of human life. According to EM-DAT (2012), about 3 billion people in more than 110 countries are affected by catastrophic flooding.

Integrated water resources management is a combination of managing blue and green water resources. Often the main focus is on the blue water resources, as information on spatially distributed evaporative water use is not as readily available as the link to river flows. Physically based, spatially distributed models are often used to generate this kind of information. These models require enormous amounts of data, which can result in equifinality, making them less suitable for scenario analyses.