Methods of Water Conservation
Exploitation of water resources has increased manifold due to the continuous increase in population, industrialisation and expansion in irrigation. Consumption of water is nearly 50 litres a day per person in rural areas and 150 litres per person in urban areas, on an average. Industries also use large quantities of water. Industrial and urban areas face scarcity of water on a regular basis. The agriculture sector is a major water consuming sector. All arable lands are using huge quantities of water for irrigation purposes. Thus, water is becoming scarce day by day.
For conserving water it is essential that rainwater is collected, It’s drainage is regulated and then it is stored for maximum utilisation. It is also necessary that suitable conditions are created so that sufficient rainwater goes underground. It will control loss of water through evaporation besides maintaining soil moisture. To ensure this, plantation of trees is essential since their roots absorb water and help accumulation of ground water. Forests thus help in maintaining the flow of water and its conservation.
Other methods necessary for conservation of water includes:
Redistribution of Water
Some areas abound in water resources while others are deficient. Redistribution of water helps in creating regional balance. River water can be redistributed in two forms: reservoirs and canals.
- Reservoirs: Rivers are dammed to create huge reservoirs which store excess water and thus help in controlling floods. In summer, when the demand is high, this stored water is utilised. Reservoirs solve the problem of energy by generating hydro-electricity. They also provide water for irrigation and for developing water transport. Besides, they supply water for domestic and industrial purposes. Though basically useful, reservoirs have some negative effects too. Large areas of fertile land are submerged under the water.
- Canals: Canals are highly useful for irrigation purposes besides serving as a means of inland transport. They provide water for various other needs of the population.
Rational Use of Underground Water
Underground water is a major source of water on the earth’s surface. It is particularly useful in areas of deficit rainfall. Its overuse has created many adverse ecological effects in USA, Australia, Mexico, Libya, etc. These adverse effects include: lowering of the water table, intrusion of saline water and subsidence of land. Therefore, rational use of underground water is required. Small reservoirs and percolation tanks can be dug to hold runoff water recharging ground water. Used water from municipal and domestic sources can be fed into pits, trenches, depressions to be filtered and percolated through the soil for recharging underground water. Also, desiltation of canals and tanks should be done regularly.
Use of Geothermal Water
Geothermal water is obtained from great depths below the earth’s surface. Hydroelectricity can be generated from this hot water. In Siberia, this hot water is used for fish breeding.
Protection of Water From Pollution
Rapid increase in population, industrialisation and means of transportation has led to an increase not only in the consumption of water but also in the pollution of lakes, rivers and oceans at an alarming rate. Pollution of lakes and rivers has assumed an alarming proportion because of discharge of industrial effluents and community waste water into them. For example, Rhine and Volga rivers are highly polluted rivers.Therefore, It is essential that waste water should be purified and reused. The effluents should not be discharged directly into water bodies. Rather, it should be treated before discharging into rivers and lakes. Some of the methods of purifying wastewater are:
- In mechanical purification methods, the dissolved materials are separated from water.
- In physio-chemical purification, chemical elements are used to purify dissolved organic and inorganic substances. Various methods including hydrolysis, electrolysis, ion exchange, absorption, coagulation, chlorination, ozonization, etc are applied.
- In biological purification method, micro-organisms are used to destroy carbonic elements dissolved in water.
Restructuring of Production Technology
Purification of river and lake water is important but it does not solve the problem completely. The amount of waste materials dissolved in water is too much to be purified. It becomes imperative then to restructure production technology in a way that minimises the amount of dissolved waste products and the level of pollution. For this, methods like water supply through closed system, safe use of raw materials, water cooling devices and technological processes requiring less amount of water need to be adopted. This technology has been successful in oil refining. According to specialists, such ecological technology used on an extensive scale will prove economical. Several chemical industries are likely to benefit from this technology.
Desalinization involves the removal of dissolved salts from water that is too salty for irrigation and human use. The two major methods of desalting are distillation and osmosis. In distillation, energy is used to evaporate fresh water from salt water to leave the salts behind. In osmosis, energy is used to force saltwater through membranes with very tiny pores that prevent the salts from passing through.
Most people think of desalinization with regard to oceans which make up 97% of our total water supply. Some people see it as a major solution to fresh water shortages but widespread use of desalinization has two major problems: economic and ecological. It is a very expensive process. Moreover, building and using a vast network of desalinization plants would release a significant amount of heat and other air pollutants.
Cloud seeding has been known to be an effective way to increase rainfall. It is a form of weather modification, a way of changing the amount of rainfall. The common chemicals used in this process include silver iodide, potassium iodide and dry ice. Liquid propane is also used sometimes. But there are some problems associated with cloud seeding. It does work in very dry areas and large scale seeding could change regional and global rainfall patterns in undesirable ways.
Water is an indispensable natural resource which is becoming scarce day by day. The future seems to be bleak in respect of availability of water resources. Therefore, its overuse needs to be controlled. It is high time now that rational exploitation of water resources is made world over.