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WATER ON THE EARTH

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India is endowed with a rich and vast diversity of natural resources, water being one of them. Its

development and management plays a vital role in agriculture production. Integrated water

management is vital for poverty reduction, environmental sustenance and sustainable economic

development.

97 percent of the water on the Earth is salt water and only three percent is fresh water; slightly over

two thirds of this is frozen in glaciers and polar ice caps. The remaining unfrozen freshwater is found

mainly as groundwater, with only a small fraction present above ground or in the air.

Fresh water is a renewable resource, yet the worlds supply of groundwater is steadily decreasing,

with depletion occurring most prominently in Asia and North America, although it is still unclear

how much natural renewal balances this usage, and whether ecosystems are threatened. The

framework for allocating water resources to water users (where such a framework exists) is known as

water rights.

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Surface water is water in a river, lake or fresh water wetland. Surface water is naturally replenished

by precipitation and naturally lost through discharge to the oceans, evaporation, and sub-surface

seepage.

Brazil is the country estimated to have the largest supply of fresh water in the world, followed by

Russia and Canada.

It is estimated that 70% of worldwide water use is for irrigation, with 15-35% of irrigation

withdrawals being unsustainable. It takes around 2,000 3,000 liters of water to produce enough

food to satisfy one persons daily dietary need.

It is estimated that 22% of worldwide water is used in industry. Major industrial users include

hydroelectric dams, thermoelectric power plants, which use water for cooling, ore and oil refineries,

which use water in chemical processes, and manufacturing plants, which use water as a solvent.

It is estimated that 8% of worldwide water use is for household purposes. These include drinking

water, bathing, cooking, sanitation, and gardening.

Environmental water usage includes watering of natural or artificial wetlands, artificial lakes

intended to create wildlife habitat, fish ladders, and water releases from reservoirs timed to help fish

spawn, or to restore more natural flow regimes.

Water pollution is one of the main concerns of the world today. Many pollutants threaten water

supplies, but the most widespread, especially in developing countries, is the discharge of raw sewage

into natural waters; this method of sewage disposal is the most common method in underdeveloped

countries, but also is prevalent in quasi-developed countries such as China, India, Nepal and Iran.

Sewage, sludge, garbage, and even toxic pollutants are all dumped into the water.