The expert appraisal committee of the ministry of environment, forest and climate change (MoEFCC) has recommended issuing coastal regulation zone (CRZ) clearance to Chennai Metro Rail Limited for constructing certain portions on the 45.8km corridor-3 from Madhavaram Milk Colony to Siruseri Sipcot, which falls under the zone.
According to a presentation made before the committee last year, CMRL said around 1220m (1.2km) of underground tunnels, around 523sqm area in Thirumayilai and 156sqm in Taramani stations, a 512sqm Buckingham Canal culvert in Thirumayilai and a 51sqm emergency evacuation shaft near Adyar river fall within the CRZ.
CMRL said the tunnels between Greenways Road Station and Adyar Junction station require an emergency evacuation shaft at the bank of Adyar as the two stations are 1200m apart.
At Thirumayilai, CMRL has proposed reconstruction of a bridge culvert, as its foundation/ pillars fall in metrorail alignment. During metrorail construction, a replacement for the existing bridge has been planned and water from the canal would be diverted.
The recommendation came with certain conditions. The panel said, “Vibration shall be monitored at a distance of 200m on either side of alignment at receptors comprising educational, medical and cultural buildings and fragile structures.
The Ground Penetrating Radar (GPR) measurements before and after tunneling should be taken up, loose strata identified from geotechnical data along alignment and regular compliance report should be submitted to the regional office,” said an EAC minutes of a meeting held on December 23, 2022.
