Allowing developers to construct on Mumbai’s salt pan lands may do more harm than good

With the Maharashtra government pressing for the development of affordable housing on Mumbai’s salt pan lands, we look at the impact that these proposals will have on the ecology of the city and measures that could mitigate the adverse effects

After a year-long delay, the final draft of the Greater Mumbai Development Plan (DP) 2034, recently saw the light of day. The highlights were the amendments in the development control regulations (DCR) in terms of increased FSI and the opening of salt pan lands for construction of affordable houses.

The DP 2034 visualises Greater Mumbai as a ‘competitive, inclusive and sustainable city’. It goes without saying that decongesting the city must be a prime focal point in such an agenda. Accordingly, the Municipal Corporation of Greater Mumbai (MCGM) has decided to utilise the city’s huge tracts of salt pan lands, for affordable housing projects.

A total of 3,355 hectares of salt pan lands are spread across Dahisar, Goregaon, Mulund, Bhandup, Kanjurmarg, Nahur, Ghatkopar, Turbhe, Mandale, Chembur, Wadala and Anik. These lands, which were classified as salt pan lands and no development zones (NDZs) for decades, are now open for new development.

According to the final draft of DP, 2,100 hectares of salt pan lands have been demarcated for the construction of 10 lakh affordable housing units, 1,100 hectares for tourism development and only 30 hectares for salt pans.

 

Ramifications of obliterating the natural buffer between the Arabian Sea and the island city

Allowing developers to construct on Mumbai's salt pan lands may do more harm than good

As per the Coastal Regulation Zone (CRZ) notification (2011) salt pan lands are ecologically sensitive areas falling under the category CRZ 1B, where no development activity is allowed, except exploration of natural gas and extraction of salts. Owing to Mumbai’s unique challenges, a concession has now been given under CRZ 2011, to redevelop the NDZ areas under public-private partnerships (PPP), with the FSI in line with the prevailing norms of the city.

See also: Congress seeks PM’s intervention, to block Mumbai DP proposals on salt pan lands

Moreover, salt pan parcels – previously categorised as wetlands according to Wetland Rules, 2017 – have been tweaked, by no longer terming them as wetlands. This provides the government with an opportunity to convert them to residential/commercial spaces.

Salt pans lands – geographically low-lying swathes in the inter-tidal lines – are crucial for Greater Mumbai, as they not only provide thousands of salt harvesters a livelihood but also help to maintain ecological balance by supporting thousands of species of migratory birds and fishes. The salt pan lands, which also have thick mangroves, act as a buffer line that protect the island city from heavy rains and floods during monsoon.

Another critical aspect that will arise from the conversion of these lands for real estate development, is that the region will be more prone to earthquakes, as the wet soil is likely to transmit earthquake vibrations rapidly.

 

How the water-locked city can mitigate the risk of future disasters

On one hand, unlocking of the salt pans in Greater Mumbai to expand its horizons as per DP 2034, comes with obvious benefits like decongesting the island city and its suburbs, rationalising property prices and boosting affordable housing. On the other hand, we have potential drawbacks such as increased vulnerability to seismic hazards, floods and accelerated corrosion of structures, due to the accumulation of huge volumes of sodium chloride on the salt pans. However, there are some measures that can be employed, while achieving the critical mass housing objectives under the Greater Mumbai’s Vision 2034.

Upgrading the existing age-old infrastructure

It is critical to assess the impact that the additional housing on the salt pan lands would have, on the existing urban infrastructure of Greater Mumbai. The creaking suburban rail network and inefficient management of both, solid waste and storm water, need to be addressed. Additionally, the ‘carrying capacity’ of the city needs to be determined – specifically, its ability to provide all citizens of Greater Mumbai a decent quality of life with access to basic amenities and infrastructural facilities.

Boosting open spaces, to manage surface water runoff

When compared to other global super cities, Greater Mumbai is seriously deprived of open spaces. As per the Urban and Regional Development Plans Formulation and Implementation (URDPFI) guidelines, 10-12 sq metres of open space must be allocated per person. Currently, only 1.24 sq metres are available in Mumbai.

Allowing developers to construct on Mumbai's salt pan lands may do more harm than good

By increasing the existing open spaces, while simultaneously preserving the 12,859 hectares of natural spaces designated in DP 2034, the city’s permeable surfaces can reduce rainfall runoff. This, in turn, aids sustainable urban development.

Creating a stable foundation, to avoid geologic hazards

Greater Mumbai basically consists of basalt beneath the ground level surface. Unlike granite, basalt’s composition is weak and disintegrates when exposed to wind and water. Around two to three years must be devoted, to stabilising the structures as the soil hardens and compacts with reduced moisture.

Also, the presence of sodium chloride makes the salt pan tracts liable to corrosion and hence, the structures built on them will be relatively less stable. Another concern with the salt pan lands, is the required depth of piling for foundations – which is 15-20 metres until rock is found, as compared to the usual 13 metre-deep foundation.

Having said that, the geological and soil aspects’ potential impact of increasing the cost of construction and the affordability of the properties built on salt lands, will only become apparent once the DP 2034 begins to materialise.

(The writer is head – research, ANAROCK Property Consultants)

 

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