Mexico City: -
30 million which is expected to grow more
As the increase of population of the city of
than 40 million in the next 20 years. To feed
Mexico has risen to a great degree, there is a
this growth, there has been unchecked
dramatic subsidence due to extraction of
pumping of deep groundwater. This water,
water to meet the demand. The European
hundreds of meters below the city, is not
Space
aerial
easily refilled and those dry cavities greatly
composite image, using satellite imagery
exaggerate city’s subsidence. A 30 km.
showing city’s rate of subsidence, which is
seawall, meant to prevent the ocean from
as much as one inch per month. Further, the
flooding, has been built, but that too is
city is mostly constructed with atop layers of
sinking. Brinkman, a Hydrologist with
clay and highly permeable sand and gravel,
Dutch Water Research Institute argues that
when the type of ground is most liable to
the city needs to take more control
collapse, as water is being pulled out. Some
groundwater pumping limiting to some
parts of the city have shrunk more than 30
extent. …….. (To be continued.)
Agency
has
created
an
over
feet during last century. Extended periods of
drought in the future make the problem
NEWS
worse for the city and other cities also which
1.
are prone to the subsidence.
Jakarta:- The city of Jakarta, Indonesia is
susceptible to rising oceans, with about 40%
of land below sea level. In addition, the city
has
been
carelessly
pumping
its
groundwater, leading neighbourhoods
to
Chennai Flood: - A Deluge makes
Chennai an island
A devastating flood has occurred after
weeks of heavy rainfall with a maximum of
600 mm. on 2.12.2015. Hundreds of soldiers
and sailors from Indian Armed Force have
been deployed to assist in relief works of
flood affected people. The calamity has left
sink further.
more than 250 lives and loss of immense
Venice and Ho Chih Minh city face similar
property.
problems. But unlike Venice, which is
Besides natural disaster, a few man-made
subsiding at a rate of about 2 mm per year or
causes have been thought of which can be
Ho Chih Minh city, which is sinking about 2
described as below:
cm. per year, parts of Jakarta are sinking at
I.
Chocking of exit way of water
10, 15 or even 20 cm. / year. Current
Chennai has three main east flowing rivers
metropolitan population of the city is about
viz. Kosasthalayer, Cooum and Adyar,
2
Integrated River Basin Management Society