Urban rainwater harvesting
Urban centres in India are facing an
ironical situation today. On one hand there is the acute water
scarcity
and on the other, the streets
are often flooded during the monsoons. This has led to serious
problems with quality and quantity of groundwater.
This is despite the fact that all these cities receive good
rainfall.
However, this rainfall occurs during short spells of high intensity.
(Most of the rain falls in just 100 hours out of 8,760 hours
in a year). Because of such short duration of heavy rain, most
of the rain falling on the surface tends to flow away rapidly
leaving very little for recharge of groundwater. Most of the
traditional water harvesting systems in cities have been neglected
and fallen into disuse, worsening the urban water scenario.
One of the solutions to the urban water crisis is rainwater
harvesting - capturing the runoff.
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Water harvesting
system at
CSE's office in Delhi
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This is practiced on a large scale in cities like Chennai,
Bangalore and Delhi where rainwater harvesting is a part of
the state policy. Elsewhere, countries like Germany, Japan,
United States, and Singapore are also adopting rainwater harvesting.
Why
to harvest rain?
n
In areas where there is inadequate groundwater supply
or surface
resources are either lacking or insufficient,
rainwater harvesting offers an ideal solution.
n Helps in utilising the primary source
of water and prevent the runoff from
going into sewer or storm drains, thereby reducing the
load on treatment plants.
n
Reduces urban flooding.
n
Recharging water into the aquifers help in improving the
quality of existing groundwater through
dilution.
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