Nearly one third of the state’s densely populated coastline from northern Raigad, through Mumbai all the way to Thane is vulnerable to severe flooding during natural disasters such as cyclonic storms and from a gradual rise in the sea level, a study has found.
While two per cent of this segment of the state’s coast is “very highly” vulnerable, 14 per cent is “highly” vulnerable and 16 per cent is “moderately” vulnerable, according to a nationwide study conducted by the Hyderbabad-based Indian National Centre for Ocean Services. The rest of Maharashtra’s coastline, i.e. the remaining 68 per cent, is at low risk because it is by and large elevated.
The institute created an index based on seven parameters, such as the shoreline change rate, coastal slope, elevation, relative sea level change, coastal geomorphology, tidal range and average significant wave height and categorised stretches of coastline into five categories of vulnerability: very high, high, moderate, low and very low.
“The Indian ocean rim is pre-disposed to natural disasters,” said T. Srinivasa Kumar, who heads the institute’s Advisory Services and Satellite Oceanography Group and prepared the index. “A rise in the sea level due to a storm surge or tsunami could lead to coastal flooding in low-lying areas or in an open coast such as a creek or river mouth, in contrast to stretches of rocky coast.”
The findings come days after the environment ministry allowed the redevelopment of old buildings in areas that fall in Coastal Regulation Zone II, which constitutes 38 per cent of the city’s coastline. “Many coastal wetlands in Mumbai and Thane are being developed as a result of these policy changes, making these areas highly vulnerable,” said Pankaj Joshi, executive director, Urban Design Research Institute.
In the West, similar indices influence urban planning because they quantify the risk posed to coastal communities.
This is the first time a vulnerability index for India’s 7,500 km coastline is being prepared, as recommended in the draft Coastal Regulation Zone notification this year. The institute will produce state-wise maps that ought to help the authorities plan and design infrastructure along the coast as well as in disaster management.
The institute has nearly finished the country-wide study: it completed its study of Maharashtra’s coast last month and needs to finish evaluating just the Gujarat coast.