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dam-l LS: CSE River Pollution Conf + Delhi Water Harvesting
Stories from CSE web site:
Right to Clean Water
The Centre for Science and Environment (CSE) aims to hold a National
Conference on Water Pollution - with special emphasis on River pollution,
in December, 1999 The aim of the conference being to get an overview of
how stressed rivers in India are, and to come with practical policy
recommendations. We propose to come out with a document based on papers
presented at the conference, as well as assist in setting up of a network
of all people working on this vital issue.
We would like NGOs, academics, scientists and others working in the
different river basins in India, keen to participate in this conference,
to send us an abstract of about 250 words on their work, by Sept 10th. We
would be especially interested to share experiences (case studies), impact
on aquatic life, health and agriculture. Kindly keep in mind the special
emphasis: river pollution. The sessions that we intend conducting at the
Conference are;
Industrial pollution.
Pollution from agricultural sources.
Impact of urban wastes.
Policy issues such as appropriate technology for pollution
control, river cleaning plans,basin approach towards
river management.
Kindly remember, your work must reach us by September 10th, 1999. A
screening committee shall go through all abstracts for final selection.
Please send abstracts / querries to Rajat Banerji, Centre for Science and
Environment.
Email: rajat@cseindia.org
_______________________________________________________
(from 'Down to Earth', CSE fortnightly magazine)
Vol 8, No 6 August 15, 1999
SPECIAL REPORT
MANNA FROM HEAVEN
Delhi is at the mercy of its riparian neighbours for water. Experts now
say, water harvesting might be a step in the right direction towards
achieving self-sufficiency in this precious resource
Every summer discussions in Delhi revolve around one word water or
rather the lack of it. Citizens, almost unfailingly, lash out at the
incompetence of the government to provide clean, potable water. The
government, religiously, promises the sky. While charges and
counter-charges are traded, concrete steps are put to the backburner. Now,
experts are proposing sustainable systems like rainwater harvesting to
mitigate this problem.
The need to harvest water in Delhi is manifold. First, surface water in
the capital suffers in terms of quality and quantity. This has increased
pressure on groundwater resources, leading to a marked decline in the
ground watertable in different parts of Delhi. The average decline of
water table during the last decade was about 0.4 metre per year. The
problems do not end here. The groundwater is brackish and the river
Yamuna, a major source of freshwater to - Delhi, contains pesticides and
chemicals like aldrin, dieldrin, heptochlor, bhc and endosulphan. Some of
these are organochlorines, which are known to cause cancer. These are
present at levels that far exceed permissible limits.
Thus, with no solution in sight for the augmentation of raw water
supplies by conventional means, the only option is to capture rainwater
where it falls. This also makes ecological, financial and political sense
while promoting community and household-based water harvesting systems. To
understand the efficacy of such an initiative, it is important to look
into the experiences of Chennai, where water harvesting has proved to be
effective.
The Chennai experiment
Acknowledging the problem facing metros today, the Chennai Metropolitan
Water Supply and Sewerage Board (CMWSSB) or Metro Water altered their
strategy from extraction-based supply to a more sustainable
conservation-based water supply system. Chennai's Rotary Club has started
the process by reviving temple tanks to solve the water scarcity in the
city. (See Down To Earth, Vol 7, No 10, October 15, 1998).
Metro Water was quick to realise the importance of saving coastal aquifers
and other groundwater potential zones in and around the city. An act to
regulate and control extraction, use or transportation of groundwater was
passed in 1987. To complement these strategies and following the 1993
drought in Chennai, Metro Water took initiatives to harvest rainwater both
at the macro and micro level. At the macro level largescale recharging of
water sources like injection wells and check dams were undertaken to
overcome sea water intrusion. At the micro level, along with Chennai
Metropolitan Development Authority (CMDA), CMWSSB made rainwater
harvesting structures compulsory for multistoried building plans which
have been submitted for approval since 1997. It is estimated about 500
complexes in Chennai have rainwater harvesting systems. Though this is not
mandatory, both agencies ensure that the structures are constructed before
the water supply and sewerage connections are provided to these buildings.
In the initial stages, the response from the builders was lukewarm. But a
sustained campaign evinced positive responses from the construction
industry.
Water harvesting in Delhi The capital receives an average annual rainfall
of 611 millimetres (mm). But
80 per cent or 4,23,663.4 million litres of water that the National
Capital Region receives per year is lost as runoff. If this water is
harvested, it can meet 50 per cent of the region's needs. Delhi also
receives 772 million litres of water per day from the river Yamuna, as
monsoon season allocation. If this water is conserved, Delhi will have a
surplus and can even supply nearby regions.
There have been efforts in Delhi to harvest rainwater. The Central Ground
Water Board (CGWB) conducted pilot projects at the Jawahar Lal Nehru
University (JNU), the Indian Institute of Technology (IIT) and in
residential areas of Malviya Nagar. Check dams and rooftop water
harvesting structures were installed at JNU. These efforts resulted in a
rise in water levels in a radius of 60m from the dams. The total storage
capacity of 49,000 cubic metres was created in these four dams and
1,25,000 cubic metres had already been restored to the aquifers. In
addition to this, capacity utilisation up to 300 per cent has already been
achieved in one of the dams. In 1998, about 8,00, 000 litres of water was
harvested from rooftop structures covering 1,666 square metres at IIT.
CSE's EFFORTS
At the invitation of President K R Narayanan, the Centre for Science and
Environment (CSE), sent experts to investigate the possibility of
rainwater harvesting at the President's Estate.After visiting the estate,
the team proposed to harvest rainwater from the estate rooftops, paved and
unpaved areas. This was calculated to be around 856.8 millimetres. The
team decided to harvest water from the rooftops of Rashtrapati Bhavan and
store it in underground tanks. The excess water will be used to recharge
dug and bore wells. The water collected in the two underground tanks (each
with a capacity of 1 lakh litres) will be used for low-quality usage. If
found acceptable, the water will also be used for drinking purposes. The
CSE team, with help from the estate engineers, has also proposed to tap
surface runoff through johads, or ponds for groundwater recharge. In
addition, the engineers are planning to divert stormwater drains for
recharging abandoned wells.
This will enable the estate to meet a part of its needs from its own water
resources, without depending on Municipal water supply and also to improve
the estate's groundwater quality, which is has traces of flourides. In
fact, this will help reduce the Rs 50 lakh bill which the estate pays to
the New Delhi Municipal Corporation as water charges.
CSE has also harvested water on its Tughlakabad office premises. Rainwater
is collected in underground tanks and used to recharge borewells. From
about 20 mm of rain water on June 21 and July 5, the centre harvested
about 2,800 litres which was stored in their tank.
The height of stormwater drains has been increased to avoid flow of
rainwater into these drains. Assuming the annual average rainfall is about
700 mm, it is estimated that from these measures about 6.7 lakh litres of
water can be reused. Around 3.3 lakh litres will be used to recharge
borewells and the rest will be collected and reused.
In March, INTACH tabled a blueprint on water augmentation through water
harvesting and recycling within Delhi. According to the report, water
harvesting and recycling will yield 675 mld and 2,205 mld, respectively.
This amount together is sufficient to close the projected demand-supply
gap at affordable costs. INTACH proposes to augment water supply by 9.8
lakh million litres per year through rooftop water harvesting and other
harvesting techniques. They also plan to use paleo-channels, village ponds
and local eco-parks to harvest water. The Central Ground Water Board
(CGWB) will extract and refill the unconfined aquifer group underlying the
Yamuna floodplains. The first phase of the scheme is expected to supply
Delhi with an additional 900 mld of water at a cost of Rs 25 crores. Pani
Morcha, an NGO, has proposed to treat 70 cusecs of sewage water that will
be pumped into the river Yamuna.
Reported by Kum Kum Das Gupta, Indira Khurana and Saravanan V S