‘We have forgotten the art of drainage. We only see land for buildings, not for water’.
Chennai is perhaps experiencing the worst impact of freak weather, but the city could have fared better had it protected and preserved its natural water bodies and drainage channels, experts at the Centre for Science and Environment (CSE) said on Thursday.
The unprecedented deluge that Chennai has been subjected to is a reminder of increasing frequency of such freak weather events across the Indian sub-continent, they said.
Speaking on the subject, CSE director-general Sunita Narain said: “We have repeatedly drawn attention to the fact that our urban sprawls such as Delhi, Kolkata, Mumbai, Chennai, Srinagar etc. have not paid adequate attention to the natural water bodies that exist in them. In Chennai, each of its lakes has a natural flood discharge channel which drains the spillover. But we have built over many of these water bodies, blocking the smooth flow of water. We have forgotten the art of drainage. We only see land for buildings, not for water.”
CSE’s research shows that Chennai had more than 600 waterbodies in the 1980s, but a master plan published in 2008 said that only a fraction of the lakes could be found in a healthy condition. According to records of the State’s Water Resources Department, the area of 19 major lakes has shrunk from a total of 1,130 hectares (ha) in the 1980s to around 645 ha in the early 2000s, reducing their storage capacity. The drains that carry surplus water from tanks to other wetlands have also been encroached upon.
The analysis also shows that the stormwater drains constructed to drain flood waters are clogged and require immediate desiltation. Chennai has only 855 km of stormwater drains against 2,847 km of urban roads. Thus, even a marginally heavy rainfall causes havoc in the city.
A number of cities including Chennai are both water-scarce as well as prone to flooding. Both problems are related — excessive construction leads to poor recharge of groundwater aquifers and blocking of natural drainage systems.
Sushmita Sengupta, deputy programme manager with CSE’s water team, said: “While Chennai has been struggling to meet its water needs and has been even desalinating seawater at a huge expense, it allowed its aquifers to get depleted.”
Chennai’s human-made drainage is no replacement for its natural drainage systems — a CSE analysis shows that there are natural canals and drains that directly connect the city with wetlands, waterbodies and rivers such as the Cooum and the Adyar that run through Chennai. The Cooum is supposed to collect surplus water from 75 tanks in its catchment area within the Chennai Metropolitan Area, while the Adyar is supposed to carry the surplus water of about 450 tanks in its catchment area and also from the Chembarambakkam tank (which is not in its catchment).
The rains in Chennai have broken a 100-year record (374 mm in just 24 hours). In November, the city had received 1,218 mm of rain, which was almost three times more than the average the city receives (407 mm).
A 2006 study by the Indian Institute of Tropical Meteorology (IITM) in Pune had said that extreme precipitation events were increasing in frequency and intensity in India during the period from 1950 to the 2000s.
CSE’s climate change experts say that while detailed attribution studies needed to be done to find out more links between the Chennai catastrophe and climate change, existing scientific studies do establish the possibility of a connection.
Over 5,000 people rescued so far by NDRF. Train service hit. Airport shut till December 6.
Chennai reels under heavy floods following record-breaking rainfall and overflowing lakes. Thousands were left homeless or stranded in their homes without food or electricity. Telephone services too took a hit in many areas.
Prime Minister Narendra Modi on Thursday flew to Chennai to take stock of the flood situation. After an aerial survey, he met with Tamil Nadu Chief Minister J. Jayalalithaa and announced Rs.1,000 crore for Tamil Nadu flood relief. He said this is in addition to the Rs. 940 crore which were released by the Centre earlier.
The floods have left over 269 dead in Tamil Nadu and 54 in Andhra Pradesh, said Home Minister Rajnath Singh in Lok Sabha. He described the situation as "alarming".
At the parlimentary meet, the Centre described the situation in Chennai as "worrisome".
Tamil Nadu Chief Minister J. Jayalalithaa today conducted an aerial survey of the flood-hit areas in Chennai and sururbs on Thursday.
The India Meterlogical Department (IMD) has predicted heavy rains for the next two to three days in Tamil Nadu.
The Airports Authority of India on Wednesday announced that operations at the Chennai airport will be shut till December 6 due to waterlogging on the runway. Many trains have been cancelled or diverted.
In case of any help and emergency tweet with #ChennaiRainsHelp and you can also look for people offering services or help here.
A view of the flooded Chennai airport runway taken from an Indian Air Force helicopter.
Latest updates:
8:06 p.m: Trujet Airlines, to operate to Arakkonam naval base airport till December 6, to offer complimentary bus service between Arakkonam & Koyambedu.
7:05 p.m: "Given the alarming situation in TN, we have ordered the suspension of toll collection on all NHs in the state till December 11, 2015," says Road Transport Minister Nitin Gadkari. He added that an order has been issued to ease rescue, relief & rehab operations being undertaken by various central and state agencies.
The severe flooding in Chennai again proves that India's cities are unprepared for extreme weather events like rains, droughts and cyclonic storms which are becoming more frequent and intense.
Many parts of India suffer flooding every year during the annual monsoon rains from June to September. The northeast monsoon has been particularly vigorous over southern India and more so in Tamil Nadu state, of which Chennai is the capital.
Last month was the wettest November in a century in the city of 4.3 million people. And, at 490 mm, rainfall on 1 December was the highest in 100 years.
The floods are a wake up call for India's teeming cities that were built with the expectation that the environment would adjust itself to accommodate the need for the city to grow.
The disconnect with nature is also manifest in the failure of planners, builders, administrators and even common people to fathom the sheer power of natural events.
The Corporation of Chennai and Chennai Metropolitan Development Authority are responsible for approving building plans and town planning, and for enforcing urban planning. A masterplan was prepared in 2008.
But much of the city has grown without a plan and with no regard to water flows, and without anticipating extreme weather events.
Then there's illegal construction.
What may have been a tank, lake, canal or river 20 years ago is today the site of multi-storey residential and industrial structures.
There are more than 150,000 illegal structures in the city, according to the city's municipality. More than 300 tanks, canals and lakes have disappeared.
An information technology park in Chennai is flooded because it is located at a place where waters from two separate lakes converge and flow to a neighbouring creek. Many of the city's info-tech facilities are built on marshlands, water-bodies and water courses. The city's famous automobile manufacturing hubs are located in the catchment area of lakes.
The premier engineering school IIT Madras has been accused of clearing more than 52 acres of forests, including 8,000 trees between 2001 and 2013 as part of a major construction spree that saw 39 renovation projects and new constructions in its campus adjoining a national park. Reports say none of the projects have local body approval or environmental clearance.
Plastics are another culprit. After the first intense downpour in mid-November, plastic trash washed into rivers by rainwater was pushed to sea by the swollen rivers.
At high-tide, the trash was thrown right back onto the city's beaches by the sea. The large quantity of plastics visible in the city's beach trash exposed another chink in the city's defences.
Plastics are virtually indestructible. What doesn't get washed out to sea tends to accumulate in water channels and storm water and sewage networks, impeding and even blocking flows.
Clearly, indiscriminate development and shoddy urban planning have led to the floods in India's fourth most populous city.
No comments:
Post a Comment