How Mumbai's natural systems are an important resource for the city's future

Sea levels are rising due to climate change. The World Bank has ranked Mumbai as one of the most vulnerable cities to sea level rise in the world fifth in terms of overall cost of damage and seventh in terms of damage measured as percentage of GDP.

The horrors of July 26, 2005 still haunt us every time there are predictions of heavy rainfall. Flash floods and landslides occur, in some capacity, every year during the monsoons. The floods, stagnant water and untreated surface runoff catalyse the spread of diseases, deterioration of ground water quality generating negative perceptions of these vulnerable urban spaces.

In response, the municipal government expands its budget to install larger storm water pipes and constructs new sewage treatment plants. However, there are no attempts made to address the root cause behind these issues ineffective top-down government regulations with general public apathy as a by-product. To better address these causes, one must first analyse the citys morphology.

Mumbai, from being an archipelago of seven islands with wetlands between them, was consolidated, first by the British and then by the Indian government into one large land mass. The city grew northwards and employment centres were set up together with housing complexes, which in turn attracted informal communities to encroach nearby.

Parallel to this growth, government organisations set up infrastructure and created spatial strategies for development in order to streamline the way for entrepreneurial agencies to populate the market. In search of this market oriented goal, naturally existing systems (mangrove forests, wetlands, rivers) were ignored, and at many places erased. The consolidation of islands resulted in most of the wetlands being sacrificed thereby, causing a shift in balance urban development replacing nature. The mangrove forests, rivers, and wetland systems that protected the coastal suburbs from high monsoon tides and floods were compromised.

Despite the municipality constructing concrete roads and building storm water drains, lack of maintenance and unchecked growth of formal and informal developments blocked these drains with solid waste. To add to this, deforesting wetlands made the city vulnerable to tidal surge, causing storm water drains to overflow back into the city during high tide.

In addition to issues of flooding, the sea level around Mumbai is projected to rise by 48cm by 2100, which, along with tidal and storm surge, could have devastating impact on the coast. There have been an insubstantial number of studies carried out on this issue. A Google search reveals some newspaper articles mentioning the possibility of sea level rise, and a general technical report from the National Institute of Oceanography in Goa.

However, thanks to public protests due to frequent floods, the remaining mangroves and wetlands have been placed under protection of the forest department and strict regulations have been set against their deforestation. Most or all the mangrove forests are now located along coastal edges of Mumbai. They have been pushed out, and rivers have been squeezed in, leaving Mumbai vulnerable to tidal waves, floods, erosions and sea level rise.

Deeper examination suggests the urban corridors of Mumbais river emerge as one of the greatest potentials to not only address issues of flooding, but also create a liveable and symbiotic urban environment. Mumbais rivers are seasonal and begin in the catchment areas in the hills of Borivali National Park, and flow via wetlands Dahisar in the north, Oshiwara towards the west, Poisar in the centre and Mithi in the southern part of Mumbai into the Arabian Sea.

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How Mumbai's natural systems are an important resource for the city's future