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 – 5th in terms of overall cost of damage and 7th
in terms of damage measured as
percentage of GDP[1]!
The horrors of 26th July, 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 catalyze 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 for installing 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 analyze the City’s morphology.
Mumbai, from being an archipelago of 7
islands with wetlands between them, was consolidated, first by the British, and
then the Indian Government into 1 large land mass. The City grew northwards and
together with housing complexes employment centres were set up which in turn attracted
informal communities to encroach nearby. Parallel to this growth, Government
organizations 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, 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 stormw water drains to overflow back into the
city during high tide hours.
In addition
to issues of flooding, sea level around Mumbai is projected to rise by 48cm by
2100, which along with tidal and storm surge could have devastating impact
along the coast. There has been insubstantial amount of studies carried out on
this issue. Google search reveals couple of newspaper articles mentioning the
possibility of sea level rise[2],
and a general technical report from the National Institute of Oceanography in
Goa[3].
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 that Mumbai’s rivers’ urban corridors emerge as one of the
greatest potentials to not only address issues of flooding, but also create a
liveable and symbiotic urban environment. Mumbai’s rivers are seasonal and
begin in the catchment areas in hills of Borivali National Park and flow via
wetlands into the Arabian Sea - Dahisar in the north, Oshiwara towards the
west, Poisar in the center and Mithi in the southern part of Mumbai.
To illustrate one framework for addressing
many of these issues, Oshiwara River’s urban corridor is chosen. It shows these
symptoms as empirical evidence of larger issues – River water and bed are
polluted due to point and non-point source pollution from the watershed. Regular
floods during monsoons in the watershed due to storm water pipe outlets getting
choked by garbage in addition to change in depth of riverbed caused by excess
sedimentation. And negative perception among people who live in or pass by this
watershed due to foul stench and unaesthetic River edge.
The root causes of these
symptoms are attributed to Government policies and their ambiguous definitions
of urban rivers at national, state and local levels. Physical Infrastructure in
Mumbai is operated and maintained by the Storm Water Department of Municipal
Corporation of Greater Mumbai (MCGM). At the State level it is the Maharashtra
Coastal Zone Management Authority that lays down measures for protecting and
improving the quality of coastal environment and preventing, abating and
controlling environmental pollution along the coast. At the national level,
Ministry of Environment and Forests sets out general guidelines for conserving
the nation’s natural resources.
This multi-layered top-down
structure complicates the implementation and maintenance of the regulations and
policies. Additionally, having unclear and ambiguous terminologies for natural
systems does not help – Urban Rivers are referred to as both nallas and rivers, depending on its
utility. For example, the Fact Finding
Committee’s report on Mumbai floods calls Oshiwara River a nalla while listing places for improving storm water drains and it
becomes a River when describing the flooded areas. The MCGM on its website
lists 3 major nallas for P South ward
– Oshiwara River being one of them. The term Nalla brings images of polluted, smelly, mosquito infested open
drains. Thus, when the government itself refers to Rivers as nallas it is no surprise that residents
perceive and treat the River as an open drain. Furthermore, despite specifying
areas under CRZ, there is no readily available information or maps illustrating
it. Thus, leading to multiple interpretations of developable land forcing the
Municipality to only be able to react retroactively.
Meanwhile, the residents and
laypersons are completely unaware of existence of these regulations. The only times
they are made aware, is when they are charged an additional Rs.6/sq.ft for
purchasing an apartment within the CRZ. This lack of awareness of ecological
issues when coupled with extra payment furthers the negative perception towards
natural systems, especially nallas …
er Rivers.
In seeking ways to address
these root causes lies the way forward. Spreading awareness of ecological
benefits that urban rivers provide, among all residents of formal and informal
housing types, is probably, one of the most important first steps. This can be
done through informational leaflets, public exhibitions, and even popular media
– movies and newspapers.
Additionally, surveys should
be administered to learn about people’s perceptions of their neighbourhood and
of the River itself. These can help planners learn about and learn from local
knowledge, to focus future policies.
Subsequently, a decentralized
approach could be proposed where the residents themselves are given control of
managing all rainfall that falls on their property – through rain water
harvesting and surface runoff treatment and detention basins. This can take
care of the load on both, Municipal infrastructure and Oshiwara River, thereby
preventing backflow during high tides. Through such inclusive approaches and
trusting local knowledge there is tremendous scope for more innovation in water
treatment and management.
Here, the Government should
be facilitator and mediator, ensuring that processes are all inclusive. There should
also be transparency in the planning stages especially for cross departmental
collaboration – storm water management, road transport, sewerage, and housing
departments. Decentralizing the process would help cut through red tape and
give more teeth to the Municipality. The blanket CRZ norms could be modified as
per local conditions based on topography, hydrology and watershed. This could
be used as an incentive for developers to use Best Management Practices for
water treatment and management within their properties.
The Government, also, has the
potential to set a precedent for rest of the City. Most of the land South of
Oshiwara River between Link Road and SV Road, is zoned as Special Planned Area
and owned by MMRDA. They have plans to create an Oshiwara Business District
here. However, the Global Sea Level Rise map suggests that a major part of this
area would be under water by 2050 and most of the rest of it by 2100! MMRDA
could use this as an opportunity to propose sea level rise resilient designs
through surrender strategies, and building a combination of horizontal and
vertical levees by planting wetlands and mangrove forests along the River’s
edge.
Following these processes
could potentially pave way for a watershed based zoning, where land use is
determined by land form and natural resources, rather than the current form of
Euclidean zoning (similar land uses grouped close to each other regardless of
physical conditions).
This need to spread public
awareness and involve local populations for making decisions is most essential
to address many issues around deterioration of Rivers’ Urban Corridors. The
importance of improving storm water drainage infrastructure and proposing sea
level rise resilient strategies along the urban corridor, illustrate the need
to integrate the site’s physiology with land use. Thus, a two pronged approach
of upgrading infrastructure sensitively, and utilizing local knowledge are most
relevant to maximize the potentials provided by Mumbai’s Rivers.
