Abstract:
Water is a precious resource essential for all forms of life. It is abundant in nature but has
significant temporal and spatial variability. With increasing population, the per capita share of water on
earth is decreasing, and in some regions has reached levels where communities face water stress and
water scarcity. Whereas lack of safe drinking water is a major problem for close to a billion inhabitants
of the earth, too much water also bring about misery, agony and destruction to many people, places and
infrastructure. The former may be attributed to the physical lack of water, pollution or unaffordability
whereas the latter is attributed mainly to population growth, urbanization and livelihood issues. Optimal
management and use of the available water in the 21st century needs a paradigm shift to a holistic
approach since all aspects of water as well as social and economic infrastructures of the world are now
more interdependent than ever before. Coping with water problems in the 21st century therefore poses
many challenges to water managers. Drinking water security, food security, energy security, climate
change, water-related disaster management and maintaining acceptable environmental quality in a
sustainable manner are among the major challenges at present and in the foreseeable future
