BANGKOK, 13 January 2010 (IRIN) - Bangkok
is likely to face such severe flooding by the middle of this century that
parts of the Thai capital may have to be abandoned unless radical action
is taken soon, experts warn.
Subsidence and poor urban planning have
resulted in the low-lying city gradually sinking between 2cm and 5cm a
year, according to researchers in Thailand.
With the added problems of rising
sea levels, which the UN International Panel on Climate Change estimates
at between 18cm and 59cm by 2050, and coastal erosion along the Gulf of
Thailand, Bangkok could soon be contending with regular flood waters up
to 2m high.
"For decades we have known
that the city was sinking because of sediment compression, but recent research
has shown that the crust of the earth itself is also depressing here, caused
by tectonic events that are totally outside our control. It is a combination
of factors," said Anond Snidvongs, the Southeast Asia regional research
director for START (global change System for Analysis, Research and Training,
a multi-national NGO).[http://start.org/]
Early warnings
Experts first sounded warnings
that Bangkok was sinking in the early 1980s. Much of the problem was caused
by water for industry being extracted from underground aquifers faster
than it could be replaced, causing the soil to compress.
Changes to the law on water use
have helped reduce the rate of soil compression, but researchers warn that
policy-makers are still not giving enough thought to the scale of future
problems.
Another issue is that many of
Bangkok's canals, which once drew comparisons with those of Venice, have
been concreted over and turned into roads, while houses and factories have
been built on the natural floodplains surrounding the capital.
During the rainy season, the canals
that are left frequently burst their banks, causing parts of the city to
flood. And while the floods at present comprise rainwater from the north,
should the sea start to flood from the south, it will put large swathes
of fertile farmland at risk of salinity.
"The problem is much larger
than the city itself - it affects four or five provinces along the coast
that need to join together and co-ordinate their efforts," Anond said.
"There are projects being
undertaken, but there needs to be a holistic approach - at the moment,
one province, for example, is planting mangroves to help reduce erosion,
which is fine, but it does little good if the neighbouring province is
doing something different.
"One approach will not solve
this - there need to be many solutions, and there needs to be a venue where
administrations and academics can pool their ideas and decide what to do.
At the moment we do not have anything like that and the response is very
fragmented."
Dike plans
Anond's view is that people and
industry will gradually be forced to abandon areas prone to flooding and
move to higher ground, with dikes being built to protect vital infrastructure
such as Suvarnabhumi Airport.
A more radical proposal is to
build a massive dike, around 100km long, right across the Gulf of Thailand
from Hua Hin to Pattaya.
The wall, which would be three
times bigger than the world's longest dike, the 33km-long Saemangeum Seawall
in South Korea, would cost hundreds of millions of dollars, but experts
are warning that the cost to the Thai economy of sea-water flooding agricultural
and industrial land could be far higher.
"I think it is a necessary
project, but so far it has not got anywhere because politicians only look
at the short-term cost," said Seree Supharatid, director of the Natural
Disaster Research Centre at Rangsit University.
"It is one of a number of
measures we should be looking at, including rebuilding the city's canals,
and acting to preserve the wetland areas and prevent any more building
on them."
The massive dike would be technically
feasible, according to Cor Dijkgraaf, a Dutch architect and urban planner.
"The sea is only around 20m deep in most places, so technically it
is no problem at all - the issue is one of cost," he said.
However, Tara Buakamsri, campaign
manager for Greenpeace Southeast Asia, warned that the environmental and
social consequences would be difficult to predict.
"There are fishing communities
all along the coast, and this would have a huge economic and social impact
on them," he said.
He agreed, however, that some
form of coordinated action was necessary.
"Bangkok has been identified
as one of the climate change hot spots - it will be one of the most affected
cities in the world... Climate change and its effect needs to be on the
national agenda and made a central part of Thailand's development plans
- it cannot be seen as a stand-alone issue."
gm/ds/mw
[END]