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Water
conservation
Our ancient religious texts and epics give a good insight
into the water storage and conservation systems that prevailed
in those days.
Over the years rising populations, growing industrialization,
and expanding agriculture have pushed up the demand for water.
Efforts have been made to collect water by building dams and
reservoirs and digging wells; some countries have also tried
to recycle and desalinate (remove salts) water. Water conservation
has become the need of the day. The idea of ground water recharging
by harvesting rainwater is gaining importance in many cities.
In the forests, water seeps gently into the ground as vegetation
breaks the fall. This groundwater in turn feeds wells, lakes,
and rivers. Protecting forests means protecting water 'catchments'.
In ancient India, people believed that forests were the 'mothers'
of rivers and worshipped the sources of these water bodies.
Some ancient Indian methods of water conservation
The Indus Valley Civilization, that flourished along the banks
of the river Indus and other parts of western and northern
India about 5,000 years ago, had one of the most sophisticated
urban water supply and sewage systems in the world. The fact
that the people were well acquainted with hygiene can be seen
from the covered drains running beneath the streets of the
ruins at both Mohenjodaro and Harappa. Another very good example
is the well-planned city of Dholavira, on Khadir Bet, a low
plateau in the Rann in Gujarat. One of the oldest water harvesting
systems is found about 130 km from Pune along Naneghat in
the Western Ghats. A large number of tanks were cut in the
rocks to provide drinking water to tradesmen who used to travel
along this ancient trade route. Each fort in the area had
its own water harvesting and storage system in the form of
rock-cut cisterns, ponds, tanks and wells that are still in
use today. A large number of forts like Raigad had tanks that
supplied water.
- In ancientmes, houses in parts of western Rajasthan were
built so that each had a rooftop water harvesting system.
Rainwater from these rooftops was directed into underground
tanks. This system can be seen even today in all the forts,
palaces and houses of the region.
- Underground baked earthen pipes and tunnels to maintain
the flow of water and to transport it to distant places,
are still functional at Burhanpur in Madhya Pradesh, Golkunda
and Bijapur in Karnataka, and Aurangabad in Maharashtra.
Rainwater harvesting
In urban areas, the construction of houses, footpaths and roads
has left little exposed earth for water to soak in. In parts
of the rural areas of India, floodwater quickly flows to the
rivers, which then dry up soon after the rains stop. If this
water can be held back, it can seep into the ground and recharge
the groundwater supply.
This has become a very popular method of conserving water especially
in the urban areas. Rainwater harvesting essentially means collecting
rainwater on the roofs of building and storing it underground
for later use. Not only does this recharging arrest groundwater
depletion, it also raises the declining water table and can
help augment water supply. Rainwater harvesting and artificial
recharging are becoming very important issues. It is essential
to stop the decline in groundwater levels, arrest sea-water
ingress, i.e. prevent sea-water from moving landward, and conserve
surface water run-off during the rainy season.
Town planners and civic authority in many cities in India are
introducing bylaws making rainwater harvesting compulsory in
all new structures. No water or sewage connection would be given
if a new building did not have provisions for rainwater harvesting.
Such rules should also be implemented in all the other cities
to ensure a rise in the groundwater level.
Realizing the importance of recharging groundwater, the CGWB
(Central Ground Water Board) is taking steps to encourage it
through rainwater harvesting in the capital and elsewhere. A
number of government buildings have been asked to go in for
water harvesting in Delhi and other cities of India.
All you need for a water harvesting system is rain, and a place
to collect it! Typically, rain is collected on rooftops and
other surfaces, and the water is carried down to where it can
be used immediately or stored. You can direct water run-off
from this surface to plants, trees or lawns or even to the aquifer.
Some of the benefits of rainwater harvesting are as follows
- Increases water availability
- Checks the declining water table
- Is environmentally friendly
- Improves the quality of groundwater through the dilution
of fluoride, nitrate, and salinity
- Prevents soil erosion and flooding especially in urban
areas
Agriculture
Conservation of water in the agricultural sector is essential
since water is necessary for the growth of plants and crops.
A depleting water table and a rise in salinity due to overuse
of chemical fertilizers and pesticides has made matters serious.
Various methods of water harvesting and recharging have been
and are being applied all over the world to tackle the problem.
In areas where rainfall is low and water is scarce, the local
people have used simple techniques that are suited to their
region and reduce the demand for water.
- In India's arid and semi-arid areas, the 'tank' system
is traditionally the backbone of agricultural production.
Tanks are constructed either by bunding or by excavating
the ground and collecting rainwater.
- Rajasthan, located in the Great Indian Desert, receives
hardly any rainfall, but people have adapted to the harsh
conditions by collecting whatever rain falls. Large bunds
to create reservoirs known as khadin, dams called johads,
tanks, and other methods were applied to check water flow
and accumulate run-off. At the end of the monsoon season,
water from these structures was used to cultivate crops.
Similar systems were developed in other parts of the country.
These are known by various local names ¾ jal talais in Uttar
Pradesh, the haveli system in Madhya Pradesh, ahar in Bihar,
and so on.
Reducing water demand
Simple techniques can be used to reduce the demand for water.
The underlying principle is that only part of the rainfall or
irrigation water is taken up by plants, the rest percolates
into the deep groundwater, or is lost by evaporation from the
surface. Therefore, by improving the efficiency of water use,
and by reducing its loss due to evaporation, we can reduce water
demand.
There are numerous methods to reduce such losses and to improve
soil moisture. Some of them are listed below.
- Mulching, i.e., the application of organic or inorganic
material such as plant debris, compost, etc., slows down
the surface run-off, improves the soil moisture, reduces
evaporation losses and improves soil fertility.
- Soil covered by crops, slows down run-off and minimizes
evaporation losses. Hence, fields should not be left bare
for long periods of time.
- Ploughing helps to move the soil around. As a consequence
it retains more water thereby reducing evaporation.
- Shelter belts of trees and bushes along the edge of agricultural
fields slow down the wind speed and reduce evaporation and
erosion.
- Planting of trees, grass, and bushes breaks the force
of rain and helps rainwater penetrate the soil.
- Fog and dew contain substantial amounts of water that
can be used directly by adapted plant species. Artificial
surfaces such as netting-surfaced traps or polyethylene
sheets can be exposed to fog and dew. The resulting water
can be used for crops.
- Contour farming is adopted in hilly areas and in lowland
areas for paddy fields. Farmers recognize the efficiency
of contour-based systems for conserving soil and water.
- Salt-resistant varieties of crops have also been developed
recently. Because these grow in saline areas, overall agricultural
productivity is increased without making additional demands
on freshwater sources. Thus, this is a good water conservation
strategy.
- Transfer of water from surplus areas to deficit areas
by inter-linking water systems through canals, etc.
- Desalination technologies such as distillation, electro-dialysis
and reverse osmosis are available.
- Use of efficient watering systems such as drip irrigation
and sprinklers will reduce the water consumption by plants.
Water conservation
The most important step in the direction of finding solutions
to issues of water and environmental conservation is to change
people's attitudes and habits¾this includes each one of us.
Conserve water because it is the right thing to do. We can follow
some of the simple things that have been listed below and contribute
to water conservation.
- Try to do one thing each day that will result in saving
water. Don't worry if the savings are minimal¾every drop
counts! You can make a difference.
- Remember to use only the amount you actually need.
- Form a group of water-conscious people and encourage your
friends and neighbours to be part of this group. Promote
water conservation in community newsletters and on bulletin
boards. Encourage your friends, neighbours and co-workers
to also contribute.
- Encourage your family to keep looking for new ways to
conserve water in and around your home.
- Make sure that your home is leak-free. Many homes have
leaking pipes that go unnoticed.
- Do not leave the tap running while you are brushing your
teeth or soaping your face.
- See that there are no leaks in the toilet tank. You can
check this by adding colour to the tank. If there is a leak,
colour will appear in the toilet bowl within 30 minutes.
(Flush as soon as the test is done, since food colouring
may stain the tank.)
- Avoid flushing the toilet unnecessarily. Put a brick or
any other device that occupies space to cut down on the
amount of water needed for each flush.
- When washing the car, use water from a bucket and not
a hosepipe.
- Do not throw away water that has been used for washing
vegetables, rice or dals¾use it to water plants or to clean
the floors, etc
- You can store water in a variety of ways. A simple method
is to place a drum on a raised platform directly under the
rainwater collection source. You can also collect water
in a bucket during the rainy season.
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