Following the unprecedented deluge of the December 2015 floods, when large swathes of the city of Chennai was inundated, civic authorities and the Tamil Nadu state government came under severe criticism. One reason for outrage against the authorities was their failure to manage the release of water from the Chembarambakkam reservoir, delaying the release for reasons best known to them, and when push came to shove, letting out a massive one lakh cusecs of water into the Adyar River, which was already in spate.
The other reason, for the flak the authorities got, was their failure to desilt and maintain water bodies in Chennai, Kanchipuram and Tiruvallur districts, the overflow of which went into the Adyar River, adding to its fury. Senior officials in the Public Works Department (PWD) of the state, responsible for dredging river mouths and desilting lakes and ponds, admit in private that the Adyar River mouth was not kept completely open as the routine tender process for the dredging got delayed. By the time work began, they say, it was simply too late.
The Assembly elections arrived then, and the desilting and dredging work that should have gone into fast track mode after such a terrible flood, went into limbo instead. Political bosses got busy with campaigning and the model code of conduct kicked in, effectively putting paid to any further preemptive civic action. With the new government in place since May, and local body elections scheduled around October, civic authorities have now shifted to high gear — zealously doing just about anything in an effort to show voters, concrete flood mitigation actions were taken by the government.
Environmental activists are furious about what they are terming a knee-jerk move by the PWD. In an effort to keep the IT Corridor from flooding this year, PWD officials have decided to widen the mouth of the Muttukadu Estuary, one of the points where river water drains into the sea. Their logic — if the point where river water enters the sea is made bigger, more water can flow out and floodwaters will recede quickly.
But environmental activists are unhappy. “PWD officials have used 15 JCB earthmovers to dredge the mouth of the Muttukadu Estuary saying that this will help in flood control,” said KVRK Thirunaran, an activist. “They will destroy the whole Pallikaranai marshland, which is the best natural flood control mechanism available in our city,” he said.
An environmental disaster in the making
Wetlands or marshes are a unique water system where water of upto around six metres stagnates on the ground. With a mix of saline sea water and freshwater from rivers, the ecology of the marsh is unique. Marshes are like sponges. They absorb excess water and hold them, ensuring the surrounding areas do not get flooded. Chennai, originally, was composed of thousands of wetland ecosystems, most of which have been lost — they have been built over by real estate developers and government. The Pallikaranai marsh, about 50 square kilometers in all, has been announced as a reserved forest by the state government since 2013.
“The specialty of a marsh is that during the rains, the marsh will absorb water and then release it slowly into the sea, ensuring the city does not flood,” continued Thirunaran. “A marsh needs to have water in it through the year. That is how it is a working thriving marsh. If it becomes dry, the marsh loses the ability to absorb water. Now, thanks to the new canal being cut by PWD, the marsh is drying up rapidly. It will not be of any use in controlling floods,” he warned.
The Pallikaranai marsh is also crucial for the adjoining Tambaram, Velachery, Medavakkam and Thiruvanmiyur areas, much of Chennai’s prized IT Corridor. The existence of this protected marshland ensures that the ground water in all of these surrounding areas is kept recharged. Tens of thousands of residents in these areas will go thirsty if the marsh dries up.
Not only has the Muttukadu Estuary been dredged dangerously, the PWD is also planning to connect the Taramani-Velachery Canal and the Veerangalodai floodwater canal directly with the south Buckingham canal. This too is part of the civic authority’s plan for flood mitigation.
“We have failed to protect the marsh which protected us during the floods,” said Jayshree Vencatesan of environmental non-profit Care Earth.
This, activists warn, would ensure that river water does not head into the Pallikaranai marsh but directly into the sea — meaning that the marsh would dry up and die very soon. “We are headed towards a large-scale environmental disaster,” opined Thirunaran.
PWD officials spoke to Firstpost only on the condition of anonymity. “When the floods happened in December, Chennai turned into small islands,” said one senior official within the PWD. “Rescue work was almost impossible in many areas. Our only goal is to ensure that flood waters recede quickly from the city. We are in a situation where we cannot worry about what will happen in the future. We need to act now. We have dredged and deepened the mouths of the Coovum, Adyar and Muttukadu Estuary,” he said.
Chennai’s residents await the North East monsoon in a few months from now, many with apprehension, as the memories of the December deluge are still fresh. Whether these measures by the PWD will actually work is anyone’s guess. But the state government is yet to begin the process of looking at and implementing long term environmentally-sustainable solutions to the problem of frequent floods in its capital city.
First Published On : Jul 18, 2016 14:08 IST