Jakarta drops 25cm per year: study

Jakarta has 10 million residents and the Indonesian capital is the fastest-sinking city in the world with parts expected to be underwater by 2050, according to Heri Andreas of the Bandung Institute of Technology.

More than 50 people died in one of Jakarta’s deadliest floods in 2007 and five years ago much of the centre was inundated after canals overflowed.

The capital sits on a swamp with 13 rivers running through it and north Jakarta is sinking by about 25cm every year and almost half the city now sits below sea level.

The sinking is partly down to the excessive extraction of groundwater for drinking water, bathing and other everyday purposes. Piped water is unreliable or unavailable in most areas so people have no choice but to pump water from aquifers deep underground.

But when groundwater is pumped up, the land above sinks and subsides.

“The walkways are like waves, curving up and down, people can trip and fall,” said Ridwan of Muara Baru, one of the worst affected areas.

As the water levels underground are depleted, the ground is sucked downwards and shifting, creating an uneven and unstable surface.

In February television channels showed fast-running muddy rivers gushing down roads, bringing down trees and homes in the hills around Jakarta.

The authorities were forced to release water from a reservoir upstream in Bogor as water levels triggered alerts.

But the problems are most acute on the coast of the Java Sea.

North Jakarta houses one of Indonesia’s busiest seaports, Tanjung Priok, where the River Ciliwung meets the Java Sea. Dutch colonists chose to spot in the 17th century to build their main port.

Around 1.8 million people live in the district, including a substantial population of wealthy Chinese Indonesians.

Fortuna Sophia has an exclusive villa with a sea view and cracks in the walls and pillars. Flood water regularly submerges the pool.

“We just have to keep fixing it,” she said of her swimming pool. “The maintenance men say the cracks are caused by the shifting of the ground. The seawater flows in and covers the swimming pool entirely. We have to move all our furniture up to the first floor.”

But property developers continue to build luxury apartments in North Jakarta. Indonesia’s Association of Housing Development chief, Eddy Ganefo, said he had called for an end to development but “so long as we can sell apartments, development will continue”.

North Jakarta is sinking particularly fast. Picture credit: Wikimedia