Encroachment and construction on Adyar and Cooum river beds, conversion of wetlands to ‘residential use zones’ continue unabated even as Chennai braces for a battering by the Northeast monsoon
In the immediate aftermath of the floods, the Comptroller and Auditor General (CAG) had conducted a survey across the city, more importantly along the Adyar stretch, to assess the situation and the decisions that had led to the catastrophe. The CAG suggested opening Chembarambakkam lake before it reached reaching full capacity to reduce chances of flooding. It also pointed out several structures constructed on the river’s course where the bed had dried. An example of which are the piers built by Metro Rail near Ekkatuthangal. “The base of the piers are built above the surface which obstructs the free flow of flood water. A low water crossing below a bridge on the river connecting Ekkatuthangal and Jaffarkhanpet also obstructs the flow of water,” the report said.
The low crossing was partially damaged in the flood, but was repaired soon afterwards. This despite the report pointing out that the crossing was redundant. “The low water crossing has been used by the local people and it helps during traffic snarls on the bridge above,” an official said.
The CAG also pointed out that the secondary runway created in Chennai Airport increased the possibilities of inundation in the surrounding areas. “The findings of the Anna University were proved right as the airport and adjoining areas were severely inundated during 2015 floods. The pillars acted as filth accumulators,” the report said.
Meanwhile, according to sources, the Airport Authority of India has begun to desilt Adyar near the airport to prevent flooding in the area and those around it. But, two sluice gates, which were proposed by IIT Madras after the floods, are yet to be installed, the sources said.
The CAG also alleged that water discharged indiscriminately from Chembarambakkam lake aggravated the situation immensely.
“Twenty nine thousand cusecs of water was discharged on December 1 even when the lake could hold another 0.268 TMC (thousand million cubic feet) of water. This was done to save the patta lands around the lake from inundation,” the CAG stated. Interestingly, the water resources department is yet to take any steps to acquire the patta land.
An official from the department, however, said, “The Chembarambakkam lake reached its capacity rapidly as it has a catchment area of a massive 900 square kilometres. Also, the bunds of smaller lakes located higher than Chembarambakkam were broken down illegally to prevent flooding in surrounding villages. This worsened the condition as Chembarambakkam not only received heavy rainfall in its catchment areas, but also excess water from other lakes.”
The official added that Adyar now has a discharge capacity of more than 40,000 cusecs and is in no danger of causing floods unless there is a severe cloudburst.
But, even after the CAG pointed out the depletion of water bodies across the city, the Chennai Metropolitan Development Authority (CMDA) continued to allow the conversion of wetlands to residential use zones. According to the CAG, during the 13 years between the first master plan and second master plan, the CMDA allowed 439 land use conversions from agricultural zone (1,229 hectares), open space and recreation zone (345 hectares) and sensitive areas such as water bodies (14 hectares).
“During the preparation of master plans, the local authority had included many patta lands into the boundary of water bodies inadvertently. When the land owners approached CMDA with patta documents, we cannot deny the land use conversion. We will have to check the validity of patta before issuing conversion orders,” an official from CMDA said.