World Bank report reveals 30% Chennai footpaths flood-prone

CHENNAI: A detailed vulnerability assessment on Chennai's transport network, conducted by the World Bank, has revealed that about 30 per cent of the total footpath network in the metropolis is vulnerable to climate extremes like flooding and inundation.

As per the assessment report, of the total 850 kilometres network of footpaths in Chennai Metropolitan Area (CMA), around 250 kilometres (30 per cent) is likely to be inundated. Moreover, 6 per cent of the footpath network is in very high or high vulnerability categories. The assessment was conducted by superimposing the footpath network over flood depth maps and assessing the footpath network's relative level of exposure with floods of varied intensity.

The report recommended the government to adopt permeable pavement footpaths for all the new footpaths to be constructed and increase the slope of the combined kerb stone and gutter. Apart from the footpath network, six out of 33 MTC bus depots/terminals are found to be critical for climate vulnerabilities and two suburban railway stations and five MRTS stations are also in critical category.

Above all, 17 bridges out of 150 and 11 flyovers out of 38 in CMA are also found to be critical."The (assessment) results showed that most of the bridges and flyovers in the city were nearing their serviceability age, suggesting scope for the utilisation of Intelligent Transport Systems (ITS), in integration with the Chennai Smart City programme, for reducing disruption to services during disaster events.With three major water bodies crossing the city and most of the MRTS and metro rail systems built along them, special attention needs to be paid to the accessibility of these stations for providing the minimum operational ability during floods," the report said.

Some of the risky elements during the extreme climate events identified during assessment were Arunachala Street, Anna Main Road, VR Ramanathan Road, Pantheon Road, Mogappair Estate Road, Doveton Flyover, Pantheon Flyover, Thirumangalam Flyover, CMBT flyover, Chetpet suburban railway station, Kodambakkam sub-urban railway station and Light House MRTS station. Bus depots in Mandaveli, T Nagar and Ambattur Industrial Estate are also in the critical category.

The report suggests implementing nature-based solutions (NbS) to mitigate the impact of floods. "Green infrastructure in a heavily urbanised city like Chennai, which has limited open space and experiences high temperatures and heavy monsoons, will act as a buffer between the streets and the drains, thereby reducing the load on stormwater drains during peak floods," it added.

The World Bank analysis shows that nature-based solutions have the highest return on investments. A comparison of regular reconstruction, improved grey solutions, and nature-based solutions, brings out that nature-based solutions perform the best." Further, nature-based solutions have the highest cost-effectiveness in terms of the difference between the net tangible benefit and the cost of recovery from damages. These benefits include both tangible benefits that relate to reduction in damage costs and environmental protection, and intangible benefits to the environment (improved biodiversity), society (cleaner air), infrastructure and improved groundwater table," the report said.

FACING CLIMATE EXTREMES

*Of the total 850 km of footpath network in Chennai Metropolitan Area, around 250 km (30%) is likely to be inundated; 6% is in very high or high vulnerability class, as per the report

*The report suggests permeable pavement footpaths for new footpaths to be constructed and increase the slope of the combined kerb stone and gutter

OTHER WEAK SPOTS

6 of 33 MTC bus depots/terminals

Two suburban railway stations

Five MRTS stations

17 of 150 bridges

11 of 38 flyovers