Water Resources

Water: Some Facts and Figures

• 3/4th of Earth is covered with water.

• Out of total volume of water on Earth 97.5% exists in oceans and seas.
• About 2.5% of water is available as fresh water. And, 70% of this is present in
frozen ice in icebergs and glaciers.
• Less than 30% of freshwater is stored as groundwater.
• India receives nearly 4 percent of the global precipitation and ranks 133 in the
world in terms of water availability per person per annum.
• By 2025, it is predicted that large parts of India will join countries or regions
having absolute water scarcity.

Why there is need for Water Conservation & Management?

• In a country like India, where population is growing at a fast rate. Demand for
water is increasing.
• Indiscriminate pumping of water from tube wells leads to falling groundwater
levels. This adversely affects water availability and food security of the people in the
long.
• Increasing numbers of industries has made matter worse by exerting pressure on
existing freshwater resources.
• Electricity used by industries comes from hydroelectric power.
• Most housing societies or colonies in the cities, have their own groundwater
pumping devices to meet their water needs. In most cases these are uncontrolled
leading to depletion in ground water levels.
• Also, the scarcity may be due to bad quality of water. Much of water may be
polluted by domestic and industrial waste, chemicals, pesticides and fertilisers used in
agriculture, thus, making it hazardous for human use.
• This excess use of chemical fertilisers and insecticides has contaminated
groundwater at many places, thus, making it hazardous for human use.

DAMS- A dam is a barrier across flowing water that obstructs, directs or retards the flow, often
creating a reservoir, lake or impoundment
 Multi-Purpose River Projects

• Multi-purpose river projects large dams that serve several purposes in addition to
impounding the water of a river and used later to irrigate agricultural fields.
• They help to control flood, check soil erosion, provide water for irrigation and drinking
purpose, generate electricity for industries, villages, cities, provide inland navigation,
help in preservation of wildlife and development or fisheries.
• Dams are classified according to structure, intended purpose or height. Based on
structure and the materials used, dams are classified as timber dams, embankment
dams or masonry dams, with several subtypes.

Advantages of multi-purpose river projects are:

• Electricity generation
• Irrigation
• Water supply for domestic and industrial uses
• Flood control
• Recreation
• Inland navigation
• Fish breeding

Disadvantages of Multi-purpose river projects are:

• Affects the natural flow of river causing poor sediment flow and excessive
sedimentation at the bottom of the reservoir.
• Destroys the habitats for the rivers' aquatic life.
• Submerges the existing vegetation and soil if created on the floodplains.
• Displaces the local people of the place where it is created.
• These are unsuccessful in controlling floods at the time of excessive rainfall.
• These projects induced earthquakes, caused water- borne diseases and pests and
pollution resulting from excessive use of water.

Opposition of Multipurpose projects

• Multi-purpose projects and large dams have also been the cause of many new
environmental movements like the ‘Narmada Bachao Andolan’ and the ‘Tehri dam
Andolan’ etc.

• Large-scale displacement of local communities.

• Local people often had to give up their land, livelihood and their meagre access and
control over resources for the greater good of the nation
• Irrigation has also changed the cropping pattern of many regions with farmers shifting to
water intensive and commercial crops.
 • Excessive irrigation leads to increase in the salt content in the soil.
• Increasing the social gap between the rich landowners and the landless poor
• The dams did create conflicts between people wanting different uses and benefits from
the same Water Resources.
• In Gujarat, the Sabarmati-basin farmers were agitated and almost caused a riot over the
higher priority given to water supply in urban areas.
• Inter-state water disputes are also becoming common regarding sharing the costs and
benefits of the multi-purpose project
• Krishna - Godavari Dispute
• Kaveri Dispute
• Most of the objections to the projects arose due to their failure to achieve the purposes
for which they were built.
• Dams were constructed to control flood, but they have triggered the flood.
• Due to sedimentation in the reservoir.
• Unsuccessful in controlling floods at the time of excessive rainfall.

Rainwater Harvesting

• Is a technique of increasing the recharge of groundwater by capturing and

storing rainwater by constructing wells, percolating pits and check dams.
• Main objectives of the rainwater harvesting are:
o To meet increasing demand of water To reduce runoff.
o To avoid the flooding of roads.
o To augment the groundwater storage and raise the water table.
o To reduce groundwater pollution.
o To improve the quality of groundwater.
o To supplement domestic water requirement during summer and long dry spells

Traditional rainwater harvesting methods practiced in different parts of the country:

o In mountainous areas ‘Guls’ and ‘Kuls’ the diversion channels were built for agriculture.
o ‘Rooftop rainwater harvesting’ was commonly practiced to store drinking water,
especially in Rajasthan.
o Inundation channels for irrigation were developed in the flood plains of West Bengal.
o In arid and semi-arid regions, agricultural fields were converted into rain fed
storage structures, e.g., ‘Khadins’ in Jaisalmer and ‘Johads’ in other parts of Rajasthan.
o In semi-arid and arid regions of Rajasthan, particularly in Bikaner, Phalodi and Barmer,
all the houses had underground tanks or ‘tankas’ built inside the house for storing
drinking water. They were a part of the well-developed rooftop rainwater harvesting
system.