CHENNAI: In the narrow bylanes in Mylapore are numerous small houses that were mostly unaffected during heavy rains. Meanwhile, at posh apartment complexes, the slightest rain causes the common areas to turn into swimming pools. With the monsoons approaching, questions arise on how to avoid flooding and effectively harvest all the excess rainwater.
“Our house is over 100 years. But we have never been affected by rains; the area has natural drainage because of this tank,” says Sridhar Krishnamachari, who lives in Chitrakulam Street, pointing to the temple tank near his old house. The tank is not the pristine and vibrant water-body that it used to be, but it has managed to act as a catchment area during the rains.
Of the four tanks in this area, the main Kapaleshwar Temple tank is water-filled after numerous efforts to restore it. The Chitrakulam tank and another nearby tank of the Madhava Perumal Temple remain mostly dry, with grass and flocking pigeons. The tank in the Virupaksha Temple was dry even after the December floods, according to an audit by Rain Centre, Chennai.
“Most areas with temple tanks were traditional habitats. These neighbourhoods had a discipline, where the houses were built on an elevated spot. There is no respect for this in new neighbourhoods. Reviving this can be an important step in flood mitigation,” says Sekar Raghavan, director, Rain Centre, who is involved in reclaiming temple tanks as an advisor to the Corporation of Chennai, along with Chennai Metro Water and the Hindu Religious and Charitable Endowments Department.
Today, the tanks are the only surface water-bodies left in the city, making their preservation and importance more crucial. Attempts are being made to use these tanks as recharge ponds, by cleaning, de-silting, and diverting all the runoff water from the surrounding areas into the tanks.
While some tanks like the Marundeeshwar Temple, Thiruvanmiyur have good quality and quantity of water because of conscious maintenance and a better water table, others like the Madhava Perumal Temple remain dry. According to a database of temple tanks prepared by the C P Ramaswami Aiyar Environmental Educational Center, a majority of temples in the city have poor quality of water or no water at all. “One of the reasons for dry tanks is the lack of maintenance and blockage of inlets. Secondly, old houses do not have any rainwater harvesting; so water flows into the street to the nearest canal and gets wasted. Hence groundwater is not recharged,” explains Raghavan.
To alleviate this problem, the group is working on a system where all the excess water from surrounding streets can be diverted into the nearest tank after doing a careful analysis of the runoff patterns and slopes. “While restoring the tanks, we take the advice of the temple stapathis and use their traditional knowledge,” he adds.
Outlining traditional construction technology, Meera Natampally, explains that the tanks used a system of interlocking stones without any cement or mortar, which made it possible for water to seep through the crevices in the stone and percolate the surroundings. “It is important for a tank to allow this percolation. If it is filled with concrete, then it just becomes nothing but a watertight swimming pool,” says the architect who researches temple tanks.
“Of the 39 tanks in Chennai, there are 17 tanks identified by the government where work will begin soon,” says Raghavan. If that happens, brimming temple tanks during the monsoon season could be good news for water-scarce regions.
Nearly 39 temple tanks in the city are in need of renovation & upkeep
Adhipureeswarar Temple
Chintadripet
Adi Kesava Perumaal Temple
Mylapore
Agastishwarar Prasanna
Venkatesha Perumaa Temple
Nungambakkam
Agastishwarar Temple
Villivakkam
Angala Parameshwari Amman Temple
Choolai
Angala Parameshwari Temple
Royapuram
Arunachaleshwarar Temple
Tondairpet
Chengazhunir PUllaiyar Temple
Mannadi
Dandeeshwarar Temple
Velachery
Ekambareshwarar Temple
Park Town
Gangadeeswarar Temple
Purasaiwalkam
Kabaleeswarar Temple
Mylapore
Kalyana Varadharaja Perumal Temple
Kaaladipet
Kandaswamy Temple
Kosapet & Park Town
Karaneeswarar Temple
Saidapet
Kashi Vishwanathar Temple
George Town & Ayanavaram
Kothandaramar Temple
Mambalam
Kurungaleeswarar Temple
Koyambedu
Madhava Perumaal Temple
Mylapore
Marundeeshwarar Temple
Thiruvanmiyur
Masilamaneeshwarar Temple
Thirumullaivoyal
Parashuramalingeshwarar Temple
Ayanavaram
Parthasarathi Temple
Thiruvallikeni
Prasanna Venkata Narasimha Perumaal Temple
Saidapet
Raveeswarar Temple
Vyasarpadi
Thiruvatteeswaran Temple
Thiruvatteeswaran Pettai
Thyagarajaswami Temple
Thiruvotriyur
Virupaksheeshwarar Temple
Mylapore
The water from each tank will replenish the surrounding areas, keep the area fertile and help in reducing water scarcity. The tanks are also interconnected, and maintaining these connections is also crucial
— Meera Natampally, an architect researching temple tanks
why we need temple tanks
Chennai has 39 temple tanks, having an average depth of 4.5 metres. Through these, it is possible to harvest and conserve about 1,300,000 m3 rain water
The catchment area required to fill a temple tank located in urban surrounding has to be at least 10 times the surface area of the tank
Taking the normal rainfall as 1,200 mm, the tank could get water to a depth of 0.6 metres by direct rainfall
They can be filled to their capacity by having storm drains from the surrounding urban area directed to the tanks
(Source: Temple tank: Ancient water storage approach by Madhavi Ganesan Indian Society for Education and Environment, Indian Journal for Science and Technology)