Jakarta to build giant sea wall to curb floods

AS JAKARTA gears up for the annual rainy season, officials are rushing to break ground on what would be one of the world's largest flood mitigation projects: A giant sea wall of some 40km across the north of Jakarta Bay to keep rising sea levels in check.

Plans for the development include reclaiming land for parks along the coast, waterfront housing and commercial centres, as well as a reservoir to hold one billion cubic metres of fresh water.

Eventually, a toll road and mass rapid transit lines will run along the northern part of the wall, which would stretch from Soekarno-Hatta airport in the west till past Tanjung Priok port in the east of the city, and allow access to the harbour.

The project - to start in 2015 - will take at least two decades to complete, is part of an overall citywide strategy on flood prevention and will cost an estimated 300 billion rupiah (S$33 million), borne partly by the private sector.

"This is needed to save the capital, and has to be in place quickly," Jakarta Governor Joko Widodo (in photo above) said last Thursday.

The sea wall was first mooted several years ago by then Governor Fauzi Bowo, who commissioned a study and fleshed out some details ahead of his re-election bid last year.

Mr Widodo, who defeated him, has backed the project as critical, citing how rising tides are predicted to reach the centre of the capital within decades if nothing is done now.

A Dutch consortium is working on a masterplan for the city, commissioned by the central government, that includes the sea wall - and has proposed that the wall look like the national symbol, the Garuda eagle, from the air.

Already, the northern coastal areas regularly flood. Parts of the city are also sinking by as much as 10cm every year due to the unregulated pumping of groundwater by residents without a reliable supply of clean water otherwise.

A sea barrier some 6m high would remedy these concerns.

Construction will take place in three stages, planners say - strengthening the existing coastline, reclaiming land for islets to the north and an inner wall, and finally building the outer wall, which would stretch past 2030.

Jakarta has a population of 10 million in an area slightly smaller than Singapore, but a total of 30 million people live in the greater Jakarta conurbation.

Infrastructure consultant Scott Younger noted in a recent commentary: "Without doing something to protect the north of the city, including the functioning of the land support for Tanjung Priok, the country's main seaport, then very large areas of land will be at risk as well as trillions of dollars of commercial assets."

He cited grim forecasts: If groundwater pumping goes unchecked, parts of the north could sink to about 5m below sea level.

The giant sea wall project got a boost last week when visiting Dutch Prime Minister Mark Rutte and officials offered their country's flood-prevention expertise.

Mr Bertrand van Ee of the Water Top Sector, a Dutch government programme focused on water issues and marketing Dutch know-how, said the Jakarta area faced "one of the biggest hydraulic engineering challenges in the world" at a time of important economic and social change.

"The Netherlands has long experience in water management, especially water supply and flood management," Mr Widodo added, referring to the former colonial master's track record of reclaiming land in north-west Europe and building dykes.

The oldest canals running through Jakarta today were also drawn up by the Dutch in the 1920s, and are being dredged and expanded to fight floods.

Some accuse the government of pushing for a huge property development project under the guise of environmental mitigation.

The chairman of the traditional fishermen's association board warns that the construction would change the pattern of currents and waves, and affect the livelihood of fishermen nearby.

Said Mr Riza Damanik: "Many parties have misused the environmental crisis in Jakarta Bay to support property development."

Others fear the proposed islands created for residential development will worsen the divide between haves and have-nots, citing recent growth in new condominiums along the northern coast.

Officials have pledged to address these concerns, and experts say the wall is a must.

"Many European countries have benefited from (such walls)," Professor Indra Jaya, chairman of the Indonesian Society of Oceanologists, told a conference earlier this month.

zakirh@sph.com.sg

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