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Water is one of the prime element responsible for life on earth.
97 % of the water on the earth is salt water only 2.5 of the total water on the earth is exists as fresh water.
Around 70 % of fresh water is frozen in glaciers and ice sheets.
Only 30 % of water is stored as ground water.
Around 0.3 % of the total fresh water exists in rivers, lakes, streams, ponds and springs are natural sources of water.
The water pollution are caused by increasing industrialization and human activities.
Mostly the water bodies get polluted by industrial, municipal and agricultural wastes.
Rains in India are largely due to the monsoons.
The monsoon of South Asia is among several geographically distributed global monsoons.
It affects the Indian subcontinent.
Most of the rain falls in a few months of the year i.e. from June to September.
Irrigation in India includes a network of major and minor
canals from Indian rivers, groundwater well based
systems, tanks, and other rainwater harvesting projects
for agricultural activities.
During ancient time irrigation system were managed by
local people.
The use of stored water was strictly regulated.
The optimum cropping patterns was based on the
availability of water and on the basis of decades/
centuries of experience.
The maintenance of these irrigation systems was a
local affair.
Irrigation in India
The arrival of the British changed the irrigation
systems.
The conception of large scale projects – large dams
and canals traversing large distances were first
conceived and implemented by the British.
Mega-projects led to the neglect of the local irrigation
methods.
After independence the government took over the
administration of these systems leading to the loss of
control over the local water sources by the local
people.
Storage of adequate
water for irrigation
Hydro power generation
Water for drinking and
industrial use
Flood control
Inland navigation
Recreation
Tehri Dam in Uttarakhand
Disadvantages
1. Social problems – Displacement of large number of
peasants and tribal without adequate compensation
or rehabilitation.
2. Economic problems - Swallow up huge amounts of
public money without the generation of proportionate
benefits.
3. Environmental problems - Deforestation and the loss
of biological diversity.
Disadvantages of Constructing Dams
The following issues to be settled during construction
of dams : -
Resettlement and Rehabilitation
Environment and forests
Sedimentary issues
Socio economic issues
Safety aspects
Issues for construction of dams
Water harvesting means capturing rain where it falls or collection of runoff for productive purposes.
It also takes measure to keep that water clean by not allowing polluting activities to take place in the catchment.
Watershed management emphasises scientific conservation of soil and water.
Objectives of watershed management
increases the production and income of the watershed community
mitigates droughts and floods
increases the life of the downstream dam and reservoirs
Age old water harvesting systems in India:-
Rajasthan - Khadins, tanks and nadis
Maharashtra - Bandharas and tals
Uttar Pradesh & M.P. - Bundhis
Bihar - Ahars and pynes
Himachal Pradesh - Kulhs
Kandi belt of Jammu region - Ponds
Tamil Nadu - Eris (tanks)
Kerala - Surangams
Karnataka - Kattas
Traditional water harvesting system —an ideal setting of the khadin system
The advantages of water stored in the ground are:
It does not evaporate, but spreads out to recharge
wells
It provides moisture for vegetation over a wide area.
It does not provide breeding grounds for mosquitoes
like stagnant water collected in ponds or artificial lakes.
The ground-water is relatively protected from
contamination by human and animal waste.
Why do we need to conserve water?
What are the ways to conserve water?
Make a poster for conservation of water.
Write a slogan on ‘water conservation’.