Kochi: A study by the Indian Institute of Technology-Madras has found that Coastal Regulation Zone violations have adversely impacted the environment in Maradu municipality in Kerala's Ernakulam district and that demolition of high-rises could lead to further environmental damages.
Eight engineers from India's premier technology institute conducted the environmental assessment study after the Supreme Court had directed the demolition of all illegal structures in Maradu.
The IIT report states that wetland reclamation and mangrove destruction in Maradu between 2002 and 2014 have caused water pollution, depletion of fisheries, losses of the carbon sink, biodiversity and the protection against coastal hazards.
Google Earth images of the sites of Maradu flats taken in 2018 and 2005:
"The contamination of water bodies due to construction in the CRZ is of serious concern. It is essential to ensure that the sewage is treated properly before the effluents are discharged from the buildings in the coastal areas," the report says.
The chapter titled 'Environmental impact of constructed buildings' concludes with the crucial findings that the built-up area in Maradu municipality seems to have increased by up to three times over the past two decades.
Another worrying finding is that the vegetation area (trees and dense trees) seems to have decreased by more than half during the period.
The report, however, admits that the team did not get enough time and background information for a detailed study.
Problems of demolition
The IIT team is of the view that there could be some positive social and economic aspects if the buildings are retained. "It could avoid the loss of livelihood and the financial investment of the occupants," it says. This seems to be the stance of the state government and the major political parties as well.
"The demolition of the high-rises before the end of their service lives would lead to a significant negative impact arising from loss or waste of carbon footprint and embodied energy," the report says.
It equates the problems that could arise from the demolition of buildings to the damage caused by mangrove destruction. The report cites certain figures to substantiate the study.
"Considering an apartment having 1500 sq. ft. of carpet area in a reinforced concrete building, the wasted carbon footprint is at least about 100 tonnes of CO2. It could then be estimated that the demolition of a complex with 80 such apartments, with a service life of 50 years, would have the same negative impact as the removal of 1 sq km of mangroves, over the same period of time," it says.
The report also presents a detailed amount of waste the demolition could generate. It "would be about 450 kg/sq. m. of carpet area, of which about 65% would be concrete, and about 25% would be brick and mortar. If there is no recycling of the concrete, this implies that the demolition of a building of 100,000 sq. ft area would require about 0.1 hectare or 0.25 acres of land for the debris to be piled up, as a layer of 3 metres," it says.
According to the report, implosion by explosives seems the most appropriate method of demolition. However, it could also result in significant environmental impacts such as air pollution, noise pollution and vibration that could damage buildings nearby and disturb their occupants.
The fine material and debris could also contaminate water bodies and cover the leaves of plants.
Waste management system
The report calls for a proper waste management system before demolition.
It says that the buildings should be demolished only if the site could be subsequently and immediately restored. "Such restoration will require site preparation, removal of all building material and debris, along with about 1.5-2 metres of (filled) soil, and the implementation of an appropriate wetland restoration scheme," it says.
The report wants off-site restoration as per the 'polluter pays' principle in case the apartment complexes are not to be demolished. This means appropriate ecological restoration should be done with new wetlands to be created to compensate for the removal of mangroves as part of the land reclamation in Maradu.
Off-site restoration is an action intended to compensate for environmental damage. It mainly involves the development of a wetland where a wetland did not previously exist through appropriate physical, chemical and biological actions on the site. The main challenge in off-site restoration is the identification of a suitable site for creation of wetland.
Polluters Pay principle, adopted by the Loss of Ecology (prevention and payment compensation) Authority, mandates to recover from the polluters the amount for reversing the ecological damage.