Cultivating temple tanks
Legally armed
The President has recently approved the legal
provisions introduced to the Chennai Metropolitan Area Groundwater (Regulation) Act, 1997
by the State Assembly. Consequently, the state government has issued two orders to be
executed in and around Chennai. One, is mandatory installation of rainwater harvesting and
waste water treatment systems within a year. Two, groundwater use for non potable or
commercial purposes has been banned. Further, while granting groundwater licenses the
views of locals will be considered.
The first violation of the orders will invite a fine of Rs
2,000 (earlier Rs 500) which will go up to Rs 5,000 (earlier Rs 1,000) if the offense is
repeated. Rs 500 (earlier Rs 100) per day will be fined for further defiance. The
enforceability is an issue that concerns many.
Source: T Ramakrishnan 2002, More curbs on groundwater use, The Hindu |
Realising the pivotal role of temple tanks in maintaining
city’s hydrological balance, Chennai Corporation took up the responsibility of
restoring 38 tanks as rainwater reservoirs. With the assistance of local NGOs, the work
has started for five tanks like, Kapaleeswarar tank in Mylapore and Marudeeshwarar tank in
Thiruvanmiyur.
At Marudeeshwarar temple tank, the restoration plans also
involve diverting the rooftop water from all the surrounding houses into the tank. Even
the state Highways Department is gauging the feasibility of enriching the reservoir with
the storm water drain network on the east coast road. Worthy plans. But can be executed
only when encroachments are removed. And, here lies the acid test for the Corporation.
Besides, efforts are also being made at the community level.
One such initiative was taken in Thirunindravur, about 40 kilometres from Chennai, to
refurbish the tank of a century old lord Shiva’s temple. The local community has
formed a trust to raise funds for desiltation and to raise the compound walls. It will
check encroachments and the entry of waste water in the tank. Once operational the tank
while meeting the daily needs of the temple will also improve the surrounding water
tables.
After facing the heat of drought this year, both state and
society are turning to their traditional wisdom for respite.
|
Syndicate residency's endeavour
Syndicate residential colony of six multi-storied buildings
has installed rainwater harvesting system. It diverts rooftop runoff from an area of 4,800
sq m to either open wells or underground sump before passing it through a filtration bed.
"About 9,36,000 litres of water was conserved during this (2002) monsoon. Residents
water problem has been solved at such a low cost of Rs 60,000", shared D V
Subramanian, a consultant, who gave designs to the colony. (vijayamani@vsnl.com,
Tel: 4661743) |
Optimising benefits
 |
Storm
drain diverting water to pond |
TVS Motor Company’s efforts to harness rainwater in
two of their factories situated in Mysore and Hosur has made them water sufficient. As
they have started amassing the liquid gold (water), the cost incurred on buying it has
gone down to zero, thereby saving nearly Rs 20 lakhs annually.
The factory at Mysore covering an area of 180 acres has a sloppy terrain. Geophysical
survey indicated the poor groundwater potential of the region. From the seven borewells
drilled only one is presently operational, yielding 35,000 litres per day (l / day) - much
below the requirement of eight lakh l / day. Further, a study revealed that even if they
harvest 50 per cent of the annual 720 mm rainfall, the daily needs could be easily met.
The entire factory was landscaped in 1998. The runoff from the built up area ie, roofs
(about 40,000 sq m) and roads were diverted to storm water drains. A pond of 15 lakh l
storage capacity was built to collect surface and excessive runoff from the storm drains.
In addition, recharge structures were introduced near the existing borewell. Contour
trenches checked soil erosion while increasing the groundwater recharge rate. At an
implementation cost of Rs 1.5 lakhs, the daily water availability has risen from 3,500 l
per hour to 25,000 l per hour - meeting their present needs. To optimise their gains, TVS
has prepared a detail water conservation plan.
As the TVS plant at Hosur started expanding, the water requirements also increased from
12 lakh l / day in 1996 to 16 lakh l / day in 1999. Due to overexploitation the yield (in
terms of quantity and quality) of the borewells started depleting. The factory started
buying water. To arrest this trend, rainwater harvesting (RWH) was initiated in 1999.
A hydrological study helped in delineating the favorable areas for groundwater
recharge. A pond with a storing capacity of 12 lakh l was created to divert the runoff
from surface and rooftops. Recharge structures near the existing borewells helped in
replenishing the yields from 600 l / day to 3,600 l / day. Few shallow ponds were also dug
in the complex covering an area of 289 acres. Nearly 50 per cent of the daily consumption
is recycled and reused. Despite of receiving less than average annual rainfall for two
consecutive years, the yield of borewells remains unaffected.
Regular staff briefings on RWH helped in spreading the message across. |
