Water Scarcity And the Need For Water Conservation And Management
Though three-fourth of the earth’s surface is covered with water, only a small proportion of it is fresh water that can be used for drinking.
96.5 per cent of the total volume of world’s water is estimated to exist as oceans.2.5 per cent is fresh water. 70 per cent of this fresh water occurs as ice sheets and glaciers in Antarctica, Greenland and the mountainous regions of the world, less than 30 per cent is stored as groundwater in the world’s aquifers.
India receives nearly 4 per cent of the global precipitation and ranks 133 in the world in terms of water availability per person per annum.
Overexploitation, increased business activities etc. are some of the factors that lead to water shortage.
In order to conserve water and to solve the problem of scarcity of water we should construct dams as we used to do in ancient times. From ancient times we have been constructing hydraulic structures like dams built of stone rubble, reservoirs or lakes, embankments and canals for irrigation.
Water scarcity in most cases is caused by over exploitation, excessive use and unequal access to water among different social groups.
(i) Due to large and growing population, water resources are being over-exploited to expand irrigated areas and dry season agriculture.
(ii) Most farmers have their own wells and tube wells for irrigation to increase their produce. This leads to fall in groundwater level.
(iii) The ever-increasing industries have made matters worse by exerting pressure on freshwater resources. Much of the energy required for industries comes from hydroelectric power.
(iv) Coming up of new urban centres, changing lifestyle, more requirement of energy and water etc. have aggravated the problems.
(v) Lot of people can’t get water because they live in remote areas which are far off from water sources because they are poor and can not have their own water arrangements.
The possible solutions to tackle the problem of water scarcity are :
(i) Rainwater harvesting
(ii) Bamboo drip irrigation system
(iii) Avoiding wastage of water in day to day life activities
(iv) Recycling of used water
Groundwater is a highly overused resource because of the following reasons :
(i)Growing population has continuously created a high demand for water.
(ii)This growing population doesn’t have equal access to the sources of fresh water.
(iii)To facilitate higher food grain production for a large population, water resources are being over exploited to expand irrigated areas for dry season agriculture.
(iv)In the cities, every housing society or colony is exploiting groundwater for daily use with the help of pumping devises.
Multi-purpose projects and integrated Water Resources Management
A river project where many uses of the impounded water are integrated with one another is known as multipurpose project.
The purposes served by a multipurpose river project are: irrigation, power generation, water supply, flood control, recreation, etc.
Advantages of multi- purpose projects are:
(i) These are the main source of power generation.
(ii) They provide us with neat, pollution free and cheapest energy which is the backbone of industry and agriculture.
(iii) These projects control the floods because water storage is effectively provided for These projects have converted many, “rivers of sorrows” into “rivers of boon”.
(iv) These projects are the main source of irrigation and also help in conserving soil.
Disadvantages of multipurpose projects
(i) Due to the construction of dams, there are no adequate floods in the river. Because of this, the soil of the downstream region does not get nutrient-rich silt.
(ii) Dams also fragment rivers making it difficult for aquatic fauna to migrate for spawning, i.e., to produce eggs.
(iii) It results in the displacement of local communities.
(iv) The multi-purpose projects induce earthquake.
(v) Construction of dams causes waterborne diseases caused waterborne diseases.
Large-scale displacement of local communities as a result of which movements like the ‘Narmada Bachao Andolan’ and the ‘Tehri Dam Andolan’, etc. came into existence.
Narmada Bachao Andolan is a Non-Governmental Organisation (NGO) that activated tribal people, farmers, environmentalists and human rights activists to fight against the Sardar Sarovar Dam being built across the Narmada river in Gujarat. This was initiated in order to save trees from getting destroyed due to building of dams and to get full rehabilitation facilities from the government for the displaced people.
Rainwater harvesting is gathering, accumulating and storing of rainwater for different uses. In other words, rainwater harvesting is a technique for capturing and storing rainwater through hydro-structures such as recharge through hand pumps and abandoned dug well.
In India people have been practising rainwater harvesting for many years. This practice of water conservation is very economical and can be molded as per suits the social and cultural values of a region.
Moreover, multipurpose projects have faced resistance for different social groups. Hence, rainwater harvesting is regarded as more viable option socioeconomically.
Different methods of rainwater harvesting practised in India are:
(i)In hilly and mountainous regions, people build diversion channels like ‘gul’ or ‘kul’ in western Himalaya for agriculture.
(ii)Rooftop rainwater harvesting was commonly practised to store drinking water particularly in Rajasthan and Gujarat.
(iii)In West Bengal, people develop inundation channels to irrigate their fields.
(iv)In semi-arid regions, agricultural fields are converted into rainfed storage structures that allow the water to stand and moist the soil .
The benefits of rainwater harvesting are many, such as relief of strain on other water supply, water security etc.
Rooftop Rainwater Harvesting
Rooftop rainwater harvesting is the most common practice in Shillong, Meghalaya. Though Cherapunjee and Mawsynram situated at a distance of 55 km from Shillong receive the highest rainfall in the world, yet the state capital Shillong faces acute shortage of water.
Nearly every household in the city has a rooftop rainwater harvesting structure. Nearly 15-25 per cent of the total water requirement of the household comes from roof top water harvesting.
Tamil Nadu is the first and the only state in India which has made rooftop rainwater harvesting structure compulsory to all the houses across the state. There are legal provisions to punish the defaulters.
Rainwater harvesting in semi-arid regions of Rajasthan
(i) In semi-arid and arid regions of Rajasthan, almost all the houses traditionally had underground tanks for storing drinking water.
(ii) The tanks can be as large as big rooms.
(iii) The tanks are part of the well-developed rooftop rainwater harvesting system.
(iv) Tanks are connected to the sloping roofs of the houses through a pipe.
(v) Rain falling on these rooftops travel down the pipe and gets stored in these underground tanks.
(vi) Usually, first rainwater is not collected. It is used to clean the rooftop and the pipe.
Bamboo Drip Irrigation System
Bamboo drip irrigation system is a 200-year old system of tapping stream and spring water by using bamboo pipes, is widespread. About 18-20 litres of water enters the bamboo pipe system, gets transported over hundreds of metres, and finally reduces to 20-80 drops per minute at the site of the plant.
(a) Nearly 18-20 liters of water enter the bamboo pipe system, get transported over hundreds of meters and finally reduced to 20-80 drops per minute at the site of the plant.
(b) The flow of water into the pipes is controlled by manipulating the pipe positions.
Jawaharlal Nehru proclaimed the dams as the “temples of modern India” because :
(i) They eliminate or reduce flooding.
(ii) They provide water for agriculture.
(iii) They provide water for human and industrial consumption.
(iv) They provide hydroelectricity for houses and industries.