Water resource is an important natural resource, which is the basis of all resources, and exploitation as well as conservation of other natural resources is possible mainly due to the presence of water.
It is a renewable resource, which can be made re-usable after using it once through the process of purification.
Water alone is the only resource whose regular supply is essential for us and we get it through rivers, lakes, ponds, groundwater and other traditional water conservation areas.
Seawater can also be used, but it is necessary to remove its salinity. In present times, Libya, Qatar, Saudi Arabia, United Arab Emirates, Israel, Yemen and a few other countries are using oceanic water after purifying it.
The maximum use of water (70%) is made for irrigation whereas industries (23%) are at the second place. Only 7 per cent water is utilized for domestic and other purposes. People are using less than 10 per cent pure water available on the earth, but since this resource is not equitably distributed hence, water cannot be equally supplied at all places. Consequently, a few countries are facing grave water crisis at present. At many other places, a situation of water crisis is created in spite of availability of water because of continuous quality deterioration of available water resources.
Water resource can be utilized in the following areas:
1. In irrigation
2. In industries
3. For domestic purposes
4. For navigation
5. For canals
6. For hydropower
1. In irrigation:
Maximum use of water is made for irrigation. Surface and groundwater is used for this purpose. Surface water is used through canals and tanks whereas, groundwater is used through dug wells and tube wells. One-fourth part of the world has arid conditions, which is fully dependent on irrigation. Russia, Turkey, West Asian region, Egyptian valley, European River Basin, Laplata Basin (South America), Nigeria, Murry Darling Basin of Australia etc., are under canal area irrigation. Even in Asia, besides rain-fed areas, some areas depend on irrigation, which are important areas for crop production. Large-scale production of rice, wheat, sugarcane, cotton etc., takes place in such areas.
In some countries like China, India, Bangladesh, Southern Japan, Vietnam and Malaysia having greater burden of population, two to three crops of rice are grown, which need irrigation. Likewise irrigation is also needed for raising summer crops.
At present, some countries, which have exploited more groundwater as compared to surface water, are facing acute water problem. United States of America has been using 25 per cent groundwater and 75 per cent surface water for irrigation, whereas in countries like India, groundwater is being blindly used for irrigation while the major portion of surface water flows away without use into oceans. Consequently, water crisis is assuming dangerous proportions in India.
2. In industries:
About 23 per cent of pure water is utilized by industries. That is why most of the industries are established near water sources (bank of river or lake). Many industrial units also have their own water purifying plants so as to have regular supply of water.
Water is used in industries for making steam, condensation of steam, solutions of chemicals, washing, dyeing, printing, temperature control through humidifiers and refrigerators, smelting of iron in steel industries, coal washing, leather processing and tanning, paper pulp making, and for preparing acids and alkalies. Presently, the increasing number of industries in the wake of industrialization has greatly deteriorated the quality of water due to which scarcity of water is being felt in spite of its availability.
3. For domestic purpose:
Water is not equitably distributed in nature, but man has made adjustment with nature by developing different practices regarding use of water as per its availability. In arid regions, multipurpose use of water is made due to scarcity of water. Water is needed for drinking, cooking, bathing, washing clothes etc. in the domestic sector.
Even in cities inhabited on riverbanks, problems have arisen in spite of availability of water because cities have contaminated these water sources. London on Thames River, St. Louis on Bainjar and Kanpur, Varanasi, on river Ganges, Kolkata on river Hoogly and Delhi and Agra on river Yamuna, are also facing problems of water supply. These cities are draining domestic wastewater into rivers.
4. For navigation:
Surface water resources contained in rivers, canals and lakes are used for navigation. Direction of flow of water, quantum of water, seasonal effects, and length of rivers and canals play an important role in navigation. Rhine River of Europe is highly useful from the point of view of navigation.
Besides it, rivers Nile, Danube, Yangtze, Volga, Mississippi, St. Lawrence, Siene, Elbe, Mekong, Iravadi, Parana, Amazon, and in India rivers Brahmaputra (up to Dibrugarh) Ganges (Farakka Barrage), Godavari etc. have navigation facility. The main problems faced in navigation are virulent flow of water, hurdles during route, presence of waterfalls and streams, and floods and changes in the route of the river.
5. For canals:
Canals are constructed by the side of rivers in case of uneven surface of the soil. Canals are made for multipurpose uses of water like irrigation, navigation, hydropower, flood control etc. From the point of view of multipurpose uses of water. Grand Canal of China (1,900 km long) is most important. From the point of view of navigation, Eric Canal of United States of America, Seattle (on the Western Coast) 500 Canal are important. 500 Canal remains closed for four months during the winter season. Volga, Dnepr, Don and Danube rivers in Russia have been connected with canal system. Similarly, in southern India, transportation has developed between Vijaywada and Tidivanam on Coromandal coast through Kombaumur canal and Buckingham canal.
6. For hydropower:
Water resource is a renewable resource which can never end. Hence, as an alternative to depleting energy resources, power is being produced in different forms from water. The equatorial regions receive maximum rainfall on earth, but due to its unevenness, possible hydropower has not been produced.
In Africa, 23 per cent of hydroelectric power of the world exists but developed hydropower is only one per cent of the world’s potential. In Asia also, 23 per cent of hydropower of the world exists but developed hydropower is only eleven per cent. Similarly, in South America, as against the potential of 17 per cent hydroelectric power, developed hydropower is only four per cent.
Thus, we are expediting development by utilizing available water reserves of the water zone like oceanic water, surface and groundwater for different purposes. Many countries are utilizing seawater for drinking and irrigation purposes after purifying it.
Oceans are being mainly used for navigation. Besides, oceans are reservoirs of energy for the future. Tidal power is being produced from ocean tides. Oceans are also food reservoirs where sufficient quantity of food is found in the form of plankton fish. Many countries prepare food items from various creatures of the sea.