|
The recent flooding in Jakarta should not have had such
a severe impact had the city’s authorities anticipated the disaster, which
occurs annually during rainy season.
There are three
main aspects associated with the cause of flooding in Jakarta: Global,
regional and local. In the global aspect, Jakarta and all coastal cities in
the world face a high potential of flooding due to global warming.
Girardet and
Mendonca state in their book, A World Renewable Energy, Ecology, Equality
(2009), that about 600 million people worldwide living on small islands and
in coastal cities, such as Jakarta, are faced with a serious threat of
flooding as the sea level continues to rise due to the melting of polar ice
flows due to global warming.
From the
regional point of view, Jakarta’s flooding resulted from large amounts of
water from upstream rivers in West Java that flowed across the capital.
Deforestation
in the headwater regions because of development of farms, plantations and
housing has reduced rainwater absorption, sparking massive water flows to
lower areas and, hence, the flooding in Jakarta.
To avoid the
floods, there is a plan to develop artificial lakes to act as water
reservoirs along the West Java border outside Jakarta to take the brunt of
the overflowing river. The West Java authority is only reluctantly
providing land for this purpose.
In many
developed countries, inland waterways, such as rivers, fall under the
control of a central or regional agency, instead of the local government
areas in which the rivers are located.
England and
Wales have a number of so-called regional water authorities that manage
things like water treatment and land drainage.
To deal with
the overflow of rivers or lakes, these agencies do whatever they can to
avoid serious flooding, such as constructing artificial lakes near rivers.
According to
this concept, rivers are not possessed by local authorities, as they were
in the past, but by different water authorities that answer to the central
government. If a similar system was applied here, then the current dispute
between Jakarta and West Java would be overcome by the agency.
The third cause
of Jakarta’s flooding is the local factor. Many urban experts argue that
the lack of open spaces and green areas in Jakarta is a source of the
floods, as rainwater cannot be absorbed by the ground surface.
Being an urban
area, the city’s ground surfaces are primarily covered by hard materials in
the form of buildings, roads, parking lots and other amenities.
However, the
main purpose of greening the city is not to absorb rainwater, but rather to
reduce its air temperature.
Increased
vegetation would reduce the “hot urban-island effect” in the city. With
lower air temperatures, a tropical city can reduce its energy consumption
for cooling, and become a low-energy city.
Other than
fulfilling an aesthetic aspect, greening a city also helps to absorb carbon
dioxide and dust. Plants need carbon dioxide to grow. Measures to “green
the city” can be implemented anywhere.
They do not
have to be at ground level only; green areas can also be established on
rooftops and on a building’s walls and balconies with potted plants.
The main idea
of greening is to minimize the amount of hard material being exposed to the
sun, so that the penetration of solar radiation can be kept to minimum.
With heavy
rainfall, it is not logical to expect rainwater in tropical cities like
Jakarta to be absorbed by the ground surfaces. Countless cities in the
world that are dominated by hard ground surfaces like concrete and asphalt
remain free of flooding despite heavy rains.
The rapid
growth of Jakarta has eradicated many green spaces, seeing them replaced by
buildings, parking lots and roads. Rainwater that falls on hard surfaces
must be able to flow through water channels to lower destinations like
canals or rivers, ultimately ending up flowing out to sea. This can be done
systematically by means of an integrated drainage system.
Unfortunately,
Jakarta does not have an integrated drainage system and even lacks
appropriate water channels. Old channels, built in the 1960s are maintained
to this day, although they are no longer sufficient to accommodate the
current levels of rainwater.
Since the
ground surfaces are almost entirely covered by concrete and asphalt, the
runoff rainwater becomes 10 times greater than before and, consequently,
inundates roads and paralyzing traffic.
Constructing an
integrated drainage system is the key to overcoming Jakarta’s floods.
Although the entire surface of the city is covered by concrete and asphalt,
the city will not be flooded if it is well equipped with an integrated
drainage system.
All the runoff
water would be circulated accordingly by the water channel and directed to
the sea. The dimension of the channels is also an important consideration.
The water
channels should be sufficiently large to accommodate the runoff water and
so avoid overflowing water that causes flooding.
Beside an
integrated drainage system and an increase in the size of water channels,
there needs to be an ongoing program to dredge sediment from the city’s
rivers, canals and lakes.
The ability of
these urban waterways to contain runoff rainwater has markedly declined in
recent years due to sedimentation.
Many high-rise,
glass-box buildings have been erected in the capital, replacing a number of
old buildings. Architects argue that the new architecture improves the
city’s aesthetic look. Sadly, all the new buildings are devoid of historic
interest which, in turn, makes the city a less attractive destination for
tourists.
As a capital
city, Jakarta requires tough calculations to build. A utilitarian grand
plan is much more important than the aesthetics of the city.
Although
Jakarta is adorned with tall buildings that presumably seem opulent to
visitors and Indonesians from more remote regions, the frequent floods that
have hit the city only strengthen the argument that the capital is little
better than a third-world city; a city with no integrated utility system.
●
|
Tidak ada komentar:
Posting Komentar