Water as Leverage- Setting the scene for a call for action

Water as Leverage for Resilient Cities Asia Setting the Scene for a Call for Action Content
1.2.2
Wetland Chennai
Chennai houses some of the largest wetland
systems in South India; until recently, these swampy
areas comprised a huge open space reaching far
into the city, providing rainwater storage, fresh air
and clean water, and containing unique ecosystems
that are home to many bird and fish species.
Nowadays, due to encroachment, only 15% of
the city consists of wetland, whereas 30 years
ago this figure still amounted to 80%. Stagnant
water and the reduction of bird populations lead
to increased numbers of mosquitos, spreading
diseases like dengue fever and malaria. Moreover,
at the Perungudi landfill, located at one of the vast
wetlands of Chennai, pollution is seeping through
the surface layers of the earth, making the water of
the aquifer beneath undrinkable.
Chennai’s shore is a natural lagoon system,
with sand banks along the coast and lagoons
behind. As a natural process, Cooum River
and Adyar River are silting up, forming
sandbanks at their mouths as a result of silt
migration along the coast. This is a system
that floods naturally on a regular basis, and
only during the rainy season do the river
mouths have a direct connection to the sea.
Since the colonial period, these wetlands
have been considered wasteland, with
little limitation for urban development. The
encroachment and insufficient management
of these wetlands, the rivers and many canals
(including the Buckingham Canal) strongly
reduced the drainage capacity of the city
and have suddenly made natural inundation
an economic and human problem. The
vast construction initiatives are destroying
wetlands and creeks, and they increase land
subsidence, robbing Chennai of even more
drainage capacity. This is taking place in the
Pallikaranai wetlands, around the ‘IT corridor’
in the south of Chennai, and around the Ennore
creek and wetlands in the proximity of the
newly constructed Ennore Port in the north.
Besides the encroachment and insufficient
management of this natural system, in many
places drainage canals are clogged by solid
waste. The reduction of drainage capacity and
a tradition of building in the most vulnerable
areas, in combination with more severe
rainfall due to climate change, cause regular
floods during the monsoon season. The 2015
monsoon flood killed approximately 470
people (Parliament of India Report 198, 2016)
and displaced thousands. Besides floods
during monsoon events, Chennai suffered
heavily during the floods of the 2004 tsunami.
The wave, reportedly up to 6 meters high,
washed away 206 people.
One of the vast areas of
wetland in Chennai.
The vast creeklands
north of Chennai are
considered a blank sheet
for industrial development.
156 CHENNAI
Water Issues
PART 2/Background Information on the Partner Cities
157