Water is a prerequisite for the existence of life. but 1.5 billion people in the world don't have access to safe drinking water. Some eighty countries in the world suffer serious water shortage. It is now widely understood that pressure on water resources, especially in urban areas, is creating a serious crisis for the planet.
Check dam is a temporary structure constructed with locally available materials. The various types are brush wood dam, loose rock dam, woven wire dam etc. The main function of the check dam is to impede the soil and water removed from the watershed. These dams serve as rainfall storage tanks and were also used for minor irrigation. These dams also help to recharge the ground water level and facilitate the soil conservation and improve the moisture in the soil.
Percolation pond or, pit is another way to conserve water. It is a multipurpose conservation structure depending on its location and size. It stores water for live stock and recharges the ground water. It is constructed by excavating a depression, forming a small reservoir or, by constructing an embankment in a natural ravine or, gully to form an impounded type of reservoir.
Irrigation tank is a storage structure that irrigates crops. It is constructed below the percolation pond structure in a watershed. In South India there are about 2 million tanks irrigating about 13514 section.
Excess rainwater usually flows through agricultural fields in the form of seasonal streams. Such excess rainfall is collected into small farm ponds. This is another way to conserve water.
Tanka is a rain water harvesting system in India that developed several centuries ago.Rainwater falling from the sloping roofs of the house is collected through a pipe into an underground tank built in the main house or, in the courtyard. It is the most reliable source of drinking water in the desert towns of India.
Human beings use about 54 percent of all accessible fresh water supplies. By 2025, this share will increase to 70 per cent. This will have serious impact on all other life forms, including plants.
Water has become an issue of major concern as it is the most critical limiting factor for many aspects of life. Thus there is a constant need for conservation and management of water throughout the world.