A major six-lane elevated bridge has been proposed across the Pallikaranai marsh on the Pallavaram–Thoraipakkam Radial Road. The project aims to protect the wetland, improve floodwater movement and retain this important road connection.
What Is Being Planned?
Approximately 2–2.1 kilometres of the existing ground-level road between Chennai One IT SEZ and the Kamakshi Memorial Hospital junction is proposed to be replaced with an elevated bridge.
Once the bridge becomes operational, the road embankment below is expected to be removed. This could reconnect nearly seven hectares of land with the Pallikaranai marsh.
Why Must the Existing Road Be Removed?
The existing road cuts across the marsh and restricts the natural flow of rainwater towards Okkiyam Maduvu. Although the affected road section is about 2.1 kilometres long, its existing culverts reportedly provide only around 90 metres of space for water movement.
Nearly 15,000 cubic feet of floodwater per second may need to pass through this route during heavy rainfall. Improving this flow could help reduce flood risk in Pallikaranai, Ram Nagar, Velachery and Madipakkam.
Expected benefits
The project is primarily intended to:
- Restore the natural hydrological connection within Pallikaranai marsh.
- Improve the movement and storage of rainwater.
- Reduce the road’s barrier effect during extreme rainfall.
- Support flood mitigation in vulnerable areas such as Ram Nagar, Velachery, Pallikaranai and Madipakkam.
- Maintain the important road connection between GST Road, Chennai Airport, Velachery and OMR.
- Recover nearly seven hectares presently occupied by the road.
How Will the Bridge Be Constructed?
- Long spans of up to approximately 200 metres, reducing the number of supports placed inside the wetland.
- Supporting piers of around 2.5 metres in diameter.
- A six-lane elevated carriageway maintaining the Radial Road’s existing traffic connection.
- Minimal occupation of the marsh at ground level compared with the existing road embankment.
The final span lengths, pier locations and structural design can change when the DPR and environmental assessments are completed.
Fewer piers and the removal of the road embankment could allow water to move more freely through the wetland.
Cost and Construction Period
The civil construction cost alone is estimated at approximately ₹450 crore. As no fresh land acquisition is reportedly required, construction could take around two years after work begins.
However, major traffic diversions will be necessary during construction.
The Radial Road connects Rajiv Gandhi Salai with Velachery, Pallikaranai, Madipakkam, Keelkattalai and GST Road and currently carries nearly 1.25 lakh vehicles every day.
What Is the Current Project Status?
The bridge remains a proposal, and its Detailed Project Report is reportedly being finalised. The ₹450-crore estimate and two-year construction period should not be treated as the final sanctioned cost or confirmed completion deadline.
Official approval, environmental clearance, tender publication, contractor appointment and the construction starting date are yet to be publicly confirmed.
Why This Project Matters
Pallikaranai marsh is an important natural flood-storage area for South Chennai. Replacing the road embankment with an elevated structure could restore part of the wetland while preserving a vital transport connection between GST Road and OMR. However, its success will depend on the final hydrological design, environmental safeguards and careful execution within the marsh.