WATER
RESOURCES
71 per cent of the earth’s surface is
covered with it but fresh water constitutes only about 3 per cent of the total
water.
Water
Resources of India
1. India accounts for about 2.45 per cent of world’s surface area
2. 4 per cent of the world’s
water resources and about 16 per cent of world’s population.
3.
The total water available from precipitation in the country in a year
is about 4,000
cubic km.
4. The availability from surface water and replenish able groundwater is 1,869 cubic
km.
5.
Out of this only 60 per cent can be
put to beneficial uses
6.
Thus, the total utilisable water
resource in the country is only 1,122 cubic km.
Surface
Water Resources
1. There are four major sources of surface water
2.
These are rivers, lakes, ponds, and tanks
3. There are about 10,360 rivers and
their tributaries
longer than 1.6 km each.
4.
The mean annual flow in all the river basins in India is estimated to be 1,869 cubic km.
5.
Only about 690 cubic km (32 per cent) of the
available surface water can be utilised.
6.
Ganga, the Brahmaputra and the Barak rivers,
7.
Although account for only about
one-third of the total area in the country
8.
Have 60 per cent of
the total surface water resources.
Groundwater
Resources
1.
The total replenishable groundwater resources in the country are about 432 cubic km.
2. The Ganga
and the Brahmaputra basins, have
about 46 per cent
of the total replenishable groundwater resources.
3.
The level of groundwater utilisation is
relatively high in the river basins lying in north-western
region and parts of south India.
4.
The groundwater utilisation is very
high in the states of Punjab, Haryana, Rajasthan, and Tamil Nadu.
5.
However, there are States like Chhattisgarh, Orissa, Kerala, etc., which
utilise only a small proportion of their groundwater potentials.
6.
States like Gujarat, Uttar
Pradesh, Bihar, Tripura and Maharashtra are utilising their ground water
resources at a moderate rate.
Lagoons and
Backwaters
1.
India has a vast coastline and
the coast is very indented in some states
2.
The States like Kerala, Orissa
and West Bengal have vast surface water resources in these lagoons and lakes.
3.
Although, water is generally
brackish in these water-bodies, it is used for fishing and irrigating certain
varieties of paddy crops, coconut, etc.
Water
Demand and Utilisation
1.
India has traditionally been an
agrarian economy, and about two-third of its population have been dependent on
agriculture.
2.
Hence, development of
irrigation to increase agricultural production has been assigned a very high
priority in the Five Year Plans
3.
And multipurpose river valleys
projects like the Bhakra-Nangal, Hirakud, Damodar Valley, Nagarjuna Sagar,
Indira Gandhi Canal Project, etc. have been taken up.
4.
Agriculture accounts for most of the surface and
ground water utilisation, it accounts for 89 per cent of the surface water and 92 per
cent of the groundwater utilisation.
5.
While the share of industrial sector is
limited to 2 per cent of the surface water utilisation and 5 per cent of the
ground-water.
6.
The share of domestic sector is
higher (9 per cent) in surface water utilisation as compared to groundwater.
Demand of
Water for Irrigation
1.
The large tracts of the country
are deficient in rainfall and are drought prone.
2.
North-western India and Deccan
plateau constitute such areas.
3.
Winter and summer seasons are
more or less dry in most part of the country.
4.
Water need of certain crops
also makes irrigation necessary. For instance, water requirement of rice,
sugarcane, jute, etc. is very high which can be met only through irrigation.
5.
Provision of irrigation makes
multiple cropping possible.
6.
It has also been found that
irrigated lands have higher agricultural productivity than unirrigated land.
7.
The high yielding varieties of
crops need regular moisture supply,
8.
This is why that green
revolution strategy of agriculture development in the country has largely been
successful in Punjab, Haryana and western Uttar Pradesh.
9.
In Punjab, Haryana and Western
Uttar Pradesh more than 85 per cent of their net sown area is under irrigation.
10.
Wheat and rice are grown mainly
with the help of irrigation in these states.
11.
Of the total net irrigated area 76.1 per cent in
Punjab and 51.3 per cent in Haryana are irrigated through wells and tube wells.
12.
In fact, over withdrawals in
some states like Rajasthan, and Maharashtra has increased fluoride
concentration in ground-water
13.
This practice has led to
increase in concentration of arsenic in parts of West Bengal and Bihar.
Emerging
Water Problems
1.
The per capita availability of
water is dwindling day by day due to increase in population.
2.
The available water resources
are also getting polluted with industrial, agricultural and domestic effluents,
3.
Water quality refers to purity
of water, or water without unwanted foreign substances.
4.
Water gets polluted by foreign
matters such as microorganisms, chemicals, industrial and other wastes
5.
The Ganga and the Yamuna are
the two highly polluted rivers in the country.
Water
Conservation and Management
1.
Besides developing water saving
technologies and methods, attempts are also to be made to prevent the
pollution.
2.
There is need to encourage
watershed development, rainwater harvesting, water recycling and reuse, and
conjunctive use of water for sustaining water supply in long run.
3.
Prevention of Water Pollution
4.
Available water resources are
degrading rapidly.
5.
The Central Pollution Control
Board (CPCB) in collaboration with State Pollution Control Boards has been
monitoring water quality of national aquatic resources at 507 stations.
6.
Data obtained from these
stations show that organic and bacterial contamination continues to be the main
source of pollution in rivers.
7.
The Yamuna River is the most
polluted river in the country between Delhi and Etawah.
8.
Other severely polluted rivers
are: the Sabarmati at Ahmedabad, the Gomti at Lucknow, the Kali, the Adyar, the
Cooum (entire stretches), the Vaigai at Madurai and the Musi of Hyderabad and
the Ganga at Kanpur and Varanasi.
9.
Groundwater pollution has
occurred due to high concentrations of heavy/toxic metals, fluoride and
nitrates at different parts of the country.
10.
The legislative provisions such
as the Water (Prevention and Control of Pollution) Act 1974,
11.
Environment Protection Act 1986
12.
Have not been implemented
effectively.
13.
The Water Cess Act, 1977, meant
to reduce pollution has also made marginal impacts.
Recycle and
Reuse of Water
1.
Another way through which we
can improve fresh water availability is by recycle and reuse.
2.
Use of water of lesser quality
such as reclaimed waste-water would be an attractive option for industries for
cooling and firefighting to reduce their water cost.
3.
Similarly, in urban areas water
after bathing and washing utensils can be used for gardening.
4.
Watershed Management
5.
Watershed management basically
refers to efficient management and conservation of surface and groundwater
resources.
6.
It involves prevention of
runoff and storage and recharge of groundwater through various methods like
percolation tanks, recharge wells, etc.
7.
However, in broad sense
watershed management includes conservation, regeneration and judicious use of
all resources – natural (like land, water, plants and animals) and human with
in a watershed.
8.
Watershed management aims at
bringing about balance between natural resources on the one hand and society on
the other.
9.
Haryali is a watershed
development project sponsored by the Central Government which aims at enabling
the rural population to conserve water for drinking, irrigation, fisheries and
afforestation.
10.
The Project is being executed
by Gram Panchayats with people’s participation.
11. Neeru-Meeru
(Water and You) programme (in Andhra Pradesh)
12.
Arvary Pani Sansad (in Alwar, Rajasthan) have taken up
constructions of various water-harvesting structures such as percolation tanks,
dug out ponds (Johad), check dams, etc. through people’s participation.
13.
Tamil Nadu has made water harvesting structures in
the houses compulsory. No building can be
constructed without making structures for water harvesting.
14.
Watershed development projects
in some areas have been successful in rejuvenating environment and economy.
Rainwater
Harvesting
1.
Rain water harvesting is a
method to capture and store rainwater for various uses
2.
It is also used to recharge
groundwater aquifers.
3.
It is a low cost and
eco-friendly technique for preserving every drop of water by guiding the rain
water to bore well, pits and wells
4.
In Rajasthan, rainwater
harvesting structures locally known as Kund or Tanka Irrigation.
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