City corpn drops plans to beautify Mambalam canal

CHENNAI: After putting the residents of T Nagar in a difficult situation in November 2021, the Greater Chennai Corporation has decided to drop the ill-conceived beautification project to create recreational spots along Mambalam Canal in T Nagar.

The decision has been taken based on the recommendation of the Thirupugazh Committee that was appointed to study the reasons for the flooding. During the November floods, debris dumped in the canal to implement the project affected the flow of water to the canal from stormwater drains resulting in waterlogging for several days.

According to a GCC official, desilting, hyacinth removal, and other works will be carried out for uninterrupted water flow. “However, plan to lay a bicycle path, walkways, parks, and seating have been dropped. It is sufficient to restore the canal to its carrying capacity,” the official said.

In January 2021, the civic body floated five tenders under the Mambalam Canal restoration project to create greenery and recreational facilities along the canal that runs through T Nagar and CIT Nagar. Contractors were selected to carry out the works for a total of 1,750 metres between Vinothya Main Road and Thyagaraya Road. Mambalam canal starts near Valluvar Kottam and passes through T Nagar and CIT Nagar before draining into the Adyar river near the Nandanam Golf Course.

The project was proposed in two phases under the Smart City fund at a total cost of around Rs 106 crore. Only 5 per cent of the works were completed before the project was stopped after the floods.

Jayaram Venkatesan, convenor of Arappor Iyakkam, opined that the beautification of Mambalam is completely useless. “The civic body has spent several crores over the years. Instead of beautifying the canal, the GCC should end water stagnation,” he said.

Hydraulic study before improvement works

After stopping the beautification of the Mambalam Canal, the Greater Chennai Corporation (GCC) has decided to conduct a hydraulic study and flood modelling of the catchment area before taking up any more improvement works.

In a report submitted to the National Green Tribunal (Southern Zone), the civic body said that building debris that filled the canal was removed completely. And that the canal has been restored to its original status and free flow of rainwater is ensured.

“Any further improvement will be taken up after preparation of the hydraulic design and flood modelling of the catchment area, and after preparing a revised detailed project report (DPR),” the report added.

It may be noted that the Thirupugazh committee has recommended the civic body appoint a reputed hydraulic consultant for carrying out the study.

Hydraulic analysis is the study of water system that ensures structures are of sufficient size so that natural flooding is not worsened, and can withstand floods. Similarly, flood modelling involves developing algorithms to characterise flooding in terms of flood water depth, extent, and flow velocity.