WATER RESOURCES
Three-fourth of the Earth's surface is covered with water. Only a
small proportion of it accounts for freshwater that can be put to use.
This freshwater is mainly obtained from surface runoff and
groundwater that is continually being renewed and recharged
through the hydrological cycle.
All water moves within the hydrological cycle ensuring that water is
a renewable resource.
The moment we speak of water shortages, we immediately
associate it with regions having low rainfall or those that are
drought prone.
We visualise the deserts of Rajasthan and women balancing many
'matkas' (earthen pots) used for collecting and storing water and
traveling long distances to get water.
The availability of water resources varies over space and time,
mainly due to the variations in seasonal and annual precipitation.
Causes of Water Scarcity
Water scarcity in most cases is caused by over-exploitation,
excessive use and unequal access to water among different social
groups.
Water scarcity may be an outcome of a large and growing
population and consequent greater demands for water, and unequal
access to it.
A large population requires more water not only for domestic use
but also to produce more food.
To facilitate higher food-grain production, water resources are being
over-exploited to expand irrigated areas for dry-season agriculture.
Irrigated agriculture is the largest consumer of water.
It is needed to revolutionise agriculture through developing drought
resistant crops and dry farming techniques.
Post-independent India witnessed intensive industrialisation and
urbanisation, creating vast opportunities. Large industrial houses
are as commonplace as the industrial units of many MNCs
(Multinational Corporations ). The ever-increasing number of
industries has made matters worse by exerting pressure on existing
freshwater resources.
Industries apart from being heavy users of water, also require
power to run them. Much of this energy comes from hydroelectric
power. In India hydroelectric power contributes approximately 22
percent of the total electricity produced.
Multiplying urban centers with large and dense populations and
urban lifestyles have not only added to water and energy
requirements but have further aggravated the problem.
The housing societies or colonies in the cities, you would find that
most of these houses have their own groundwater pumping devices
to meet their water needs.
Fragile water resources are being over-exploited and have caused
their depletion in several of these cities.
Lately, there has been growing concern that even if there is ample
water to meet the needs of the people, much of it may be polluted
by domestic and industrial wastes, chemicals, pesticides and
fertilisers used in agriculture
Making it hazardous for human use.
Jal Jeevan Mission
Government of India has accorded highest priority to improve the quality
of life and enhance ease of living of people especially those living in rural
areas by announcing the Jal Jeevan Mission (JJM). The Goal of JJM is to
enable every rural household to get assured supply of potable piped water
at a service level of 55 litres per capita per day regularly on long-term
basis by ensuring functionality of the tap water connections.
Water Pollution
India's rivers, especially the smaller ones, have all turned into toxic
streams even the big ones like the Ganga and Yamuna are far from being
pure the assault on India's rivers from population growth, agricultural
modernisation, urbanisation and industrialisation - is enormous and
growing by the day. This entire life stands threatened the need of the hour
is to conserve and manage our water resources, safeguard ourselves from
health hazards, to ensure food security, continuation of our livelihoods
and productive activities and also to prevent degradation of our natural
ecosystems.
Over exploitation and mismanagement of water resources will impoverish
this resource and cause ecological crisis that may have profound impact
on our lives.
What are Dams?
A dam is a barrier across flowing water that obstructs, directs or retards
the flow, often creating a reservoir, lake or impoundment.
"Dam" refers to the reservoir rather than the structure.
Most dams have a section called a spillway or weir over which or through
which it is intended that water will flow either intermittently or
continuously 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. According to the height, dams can be categorised as large dams
and major dams or alternatively as low dams, medium height dams and
high dams.
How do dams help in conserving and managing water?
Dams were traditionally built to impound rivers and rainwater that could
be used later to irrigate agricultural fields.
Today, dams are built not just for irrigation but for electricity generation,
water supply for domestic and industrial uses, flood control, recreation,
inland navigation and fish breeding. Dams are now referred to as multi-
purpose projects where the many uses of the impounded water are
integrated with one another.
For example, in the Sutlej-Beas river basin, the Bhakra-Nangal project
water is being used both for hydel power production and irrigation. The
Hirakud Project in the Mahanadi basin integrates conservation of water
with flood control.
Multipurpose projects, launched after Independence with their integrated
water resources management approach, were thought of as the vehicle
that would lead the nation to development and progress, overcoming the
handicap of its colonial past. Jawaharlal Nehru proudly proclaimed the
dams as the temples of modern India".
The reason being that it would integrate development of agriculture and
the village economy with rapid industrialisation and growth of the urban
economy.
Negative Impacts of Dams
In recent years, multi-purpose projects and large dams have come under
great scrutiny and opposition for a variety of reasons.
Regulating and damming of rivers affect their natural flow causing poor
sediment flow and excessive sedimentation at the bottom of the reservoir,
resulting in rockier stream beds and poor habitats for the river's aquatic
life. Dams also fragment rivers making it difficult for aquatic fauna to
migrate, especially for spawning.
The reservoirs that are created on the flood plains also submerge the
existing vegetation and soil leading to its decomposition over a period of
time.
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. Resistance to these projects has primarily
been due to the 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.
Narmada Bachao
Narmada Bachao Andolan or Save Narmada Movement is a Non
Governmental Organisation (NGO) that mobilised tribal people, farmers,
environmentalists and human rights activists against the Sardar Sarovar
Dam being built across the Narmada river in Gujarat. It originally focused
on the environmental issues related to trees that would be submerged
under the aim to enable poor citizens, especially the oustees (displaced
people) to get full rehabilitation facilities from the government. People felt
that their suffering would not be in vain. Accepted the trauma of
displacement believing in the promise of irrigated fields and plentiful
harvests .
Irrigation
Irrigation has also changed the cropping pattern of many regions with
farmers shifting to water intensive and commercial crops This has great
ecological consequences like salinization of the soil. At the same time, it
has transformed the social landscape i.e. Increasing the social gap
between the richer landowners and the landless poor.
In Gujarat, the Sabarmati-basin farmers were agitated and almost caused
a riot over the higher priority given to water supply in urban areas,
particularly during droughts.
Inter-state water disputes are also becoming common with regard to
sharing the costs and benefits of the multi-purpose project.
Disadvantages of Multi-purpose projects
Most of the objections to the projects arose due to their failure to achieve
the purposes for which they were built. Ironically, the dams that were
constructed to control floods have triggered floods due to sedimentation
in the reservoir
Moreover, the big dams have mostly been unsuccessful in controlling
floods at the time of excessive rainfall. The release of water from dams
during heavy rains aggravated the flood situation in Maharashtra and
Gujarat in 2006.
The floods have not only devastated life and property but also caused
extensive soil erosion. Sedimentation also meant that the flood plains
were deprived of silt, a natural fertiliser, further adding on to the problem
of land degradation. It was also observed that the multi-purpose projects
induced earthquakes, caused water-borne diseases and pests and
pollution resulting from excessive use of water.
Hydraulic Structures
In the first century B.C, Sringaverapura near Allahabad had a
sophisticated water harvesting system channeling the flood water of the
river Ganga. During the time of Chandragupta Maurya, dams, lakes and
irrigation systems were extensively built. Evidences of sophisticated
irrigation works have also been found in Kalinga (Odisha), Nagarjunakonda
(Andhra Pradesh), Bennur (Karnataka), Kolhapur (Maharashtra), etc, In the
11th Century, Bhopal Lake, one of the largest artificial lakes of its time
was built In the 14th Century, the tank in Hauz Khas, Delhi was
constructed by Iltutmish for supplying water to the Siri Fort area.
Rainwater Harvesting
Rainwater harvesting is a simple method by which rainfall is collected for future
usage. The collected rainwater may be stored, utilised in different ways or
directly used for recharge purposes.
Different methods have been adopted in different areas for Rain Water
Harvesting.
1. In hill and mountainous regions, people have built diversion channels like
the ‘guls’ or ‘kuls’ of the Western Himalayas for agriculture.
2. Rooftop rainwater harvesting is commonly practised to store drinking
water, particularly in Rajasthan.
3. In the flood plains of Bengal, people developed inundation channels to
irrigate their fields.
4. In arid and semi-arid regions, agricultural fields were converted into rain-
fed storage structures that allowed the water to stand and moisten the soil
such as ‘khadins’ in Jaisalmer and ‘Johads’ in other parts of Rajasthan.
5. The tankas are part of the well-developed rooftop rainwater harvesting
system and are built inside the main house or the courtyard. This is mainly
practised in Rajasthan, particularly in Bikaner, Phalodi and Barmer areas
for saving rainwater. Many houses have constructed underground rooms
adjoining the ‘tanka’ to beat the summer heat as it would keep the room
cool.
Tamil Nadu is the first state in India which has made rooftop rainwater
harvesting structures compulsory for all houses across the state. There are legal
provisions to punish defaulters.
Bamboo Drip irrigation System
In Meghalaya, a 200-year-old system of tapping stream and spring water by
using bamboo pipes, is prevalent.
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 Bamboo pipes are used to divert perennial springs on the
hilltops to the lower reaches by gravity. The channel sections, made of bamboo,
divert water to the plant site where it is distributed into branches, again made
and laid out with different forms of bamboo pipes.
The flow of water into the pipes is controlled by manipulating the pipe positions.
If the pipes pass a road, they are taken high above the land Reduced channel
sections and diversion units are used at the last stage of water application. The
last channel section enables water to be dropped near the roots of the plant
