Water being one of the most essential necessity of life, becoming an increasing scare resource, needs careful planning and management. Availability of safe quality drinking water is being reduced due to pollution from sewage and industrial waste. So water should be meticulously harnessed and carefully conserved. It should be economically used and safely disposed off after usage.
The need of the hour is sustainable water management, specially in the context of meeting the demands of an increasing population. Simply put, it means managing our finite water resources for present needs while keeping in mind the future requirement of next generation. It also means looking at fresh water as an exhaustible, natural and essential resource and seeing watershed areas as sustainable units of water resource development and management
                                                            Sources of water
Rain is liquid water in the form of droplets that have condensed from atmospheric water vapor and then precipitated—that is, become heavy enough to fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth.
          A lake is an area of variable size filled with water, localized in a basin, that is surrounded by land, apart from any river or other outlet that serves to feed or drain the lake.[1] Lakes lie on land and are not part of the ocean, and therefore are distinct from lagoons, and are also larger and deeper than ponds, though there are no official or scientific definitions  
A pond is a body of standing water, either natural or artificial, that is usually smaller than a lake.[1] They may arise naturally in floodplains as part of a river system, or they may be somewhat isolated depressions.
A sea is a large body of salt water that is surrounded in whole or in part by land.[1] More broadly, "the sea" is the interconnected system of...