Jakarta mulls constructing giant seawall

The Jakarta Post 27 Jan 11;

JAKARTA: Anticipating a worsening rate of land subsidence and rising sea levels, the Jakarta administration is considering a plan to construct a giant seawall surrounding the city’s northern coast.

Jakarta Governor Fauzi Bowo said Wednesday that a feasibility study on the project had been started in December and would be completed in two or three years.

“In 2025, we are expecting to have a giant seawall protecting the capital from flooding,” Fauzi said. If approved, the wall will be erected in about 10 years.

According to a study by the Jakarta Coastal Defence Strategy (JCDS) consortium, which is partly funded by the Dutch government, land subsidence and rising sea levels caused by global warming are the two main threats to the capital’s coastal areas.

“The northern Java coastal areas are vulnerable to these threats. Within five or 10 years things will get worse,” Fauzi said.

Jakarta is one of many cities in the country located in coastal areas that are less than 10 meters above sea level.

Global sea levels have risen at a rate of about 1-2 millimeters per year on average, and this rate is expected to increase to 5 millimeters per year by 2050. A study by the Bandung Institute of Technology showed that sea levels in the Jakarta bay area were rising at a rate of 5.7 millimeters per year. — JP

Jakarta to Build Sea Wall
Tempointeractive 4 Feb 11;

TEMPO Interactive, Jakarta:Researchers from Jakarta Coastal Defense Strategy (JCDS) Consortium recommended that the Jakarta Government build a giant sea wall to manage floods. The sea wall will extend 60 kilometers from Tangerang, Jakarta up to Bekasi. “The construction is made possible because the technology has been applied in New Orleans, US,” said member of the JDCS Consortium, Heri Andreas, last Tuesday.

The sea wall was recommended to manage two big threats causing frequent flooding in Jakarta, which are ground subsidence by 10- centimeters per year and the rise of the sea level by 5 millimeter per year. The construction of the sea wall along the North coast of Jakarta is judged to be effective in reducing the threats.

Heri admitted sea walls were not the only way to manage the floods. Another method would be to stop ground water usage and refilling it back. But total stoppage would be unlikely because it is one of the main sources of water.

Even though there are plans to a water refilling plant at the Jatiluhur dam area, the Jakarta Government is still not ready to do this. “By reducing ground water intake, the ground will still subside by 10 to 15 centimeters per year. Even if we refill the water, the ground will still subside in 5 years time,” said Heru,” Meanwhile the danger of rising sea levels cannot be solved because it is caused by global warming.

Heri said that the government has tried to solve the problem partially by building embankments in Kamal Muara and other sites. But it is still regarded as insufficient.

RENNY FITRIA SARI | ENDRI K