Water For All

Water is a basic necessity for all terrestrial forms of life. Human intervention also changes the availability of water in various regions. Failure to sustain water availability underground has resulted from the loss of vegetation cover, diversion for high water demanding crops, and pollution from industrial effluents and urban wastes.

Irrigation methods like dams, tanks and canals have been used in various parts of India since ancient times. The use of this stored water was strictly regulated and the optimum cropping patterns based on the water availability were arrived and at on the basis of decades/centuries of experience and the maintenance of these irrigation systems was also a local affair. The arrival of the British changed these systems as it changed many other things.

The conception of large scale projects-large dams and canals traversing large distances were first conceived and implemented by the British and carried on with no less gusto by our newly formed independent government. These mega-projects led to the neglect of the local irrigation methods, and the government also increasingly took over the administration of these systems leading to the loss of control over the local water sources by the local people.

Water For All Definitions, Equations and Examples

Mismanagement of Water

  1. Canal systems leading from these dams can transfer large amounts of water great distances. However, mismanagement of the water has largely led to the benefits being cornered by a few people.
  2. There is no equitable distribution of water, thus people close to the source grow water-intensive crops like sugarcane and rice while people farther downstream do not get any water.
  3. The woes of these people who have been promised benefits which never arrived are added to the discontentment among the people who have been displaced by the building of the dam and its canal network.

Problems Caused by Building Dams

Criticisms about large dams address three problems in particular:

  1. Social problems because they displace large number of peasants and tribals without adequate compensation or rehabilitation.
  2. Economic problems because they swallow up huge amounts of public money without the generation of proportionate benefits.
  3. Environmental problems because they contribute enormously to deforestation and the loss of biological diversity.

Water For All Definitions, Equations and Examples

Watershed Management

  1. Watershed management emphasizes scientific soil and water conservation in order to increase biomass production.
  2. The aim is to develop primary resources of land and water, to produce secondary resources of plants and animals for use in a manner which will not cause ecological imbalance.
  3. Watershed management not only increases the production and income of the watershed community but also mitigates droughts and floods and increases the life of the downstream dam and reservoirs.
  4. Various organizations have been working on rejuvenating ancient systems of water harvesting as an alternative to the ‘mega-projects like dams.

Water Harvesting

Water harvesting is an age-old concept in India. Some of the ancient water-harvesting techniques used in different parts of our country are given below:

Region Ancient Water harvesting structure
Rajasthan Khakis, tanks and nadis
Maharashtra Banderas and tals
Madhya Pradesh and Uttar Pradesh Bundhis
Bihar Ahars and pynes
Himachal Pradesh Kulhs
Jammu region Ponds
Tamil Nadu Eris (Tanks)
Kerala Surangams
Karnataka Kattas

Water harvesting techniques are highly locale-specific and the benefits are also localized. In largely level terrain, the water harvesting structures are mainly crescent-shaped earthen embankments or low, straight concrete and rubble “check dams” built across seasonally flooded gullies. Monsoon rains fill ponds behind the structures. Only the largest structures hold water year-round; most dry up six months or less after the monsoons.

Their main purpose, however, is not to hold surface water but to recharge the groundwater beneath.

The advantages of water stored in the ground are many.

  1. It does not evaporate but spreads out to recharge wells.
  2. It provides moisture for vegetation over a wide area.
  3. It does not provide breeding grounds for mosquitoes like stagnant water collected in ponds or artificial lakes.
  4. The ground water is also relatively protected from contamination by human and animal waste.

Class 10 Science Notes