Sinking cities in Indonesia caused by groundwater and gas extraction

Rosenstiel School of Marine &Atmospheric Sciences News: Jakarta and several other major Indonesia cities are sinking at alarming rates of up to 22 cm per year, according to a new study by scientists at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science. This rapid land subsidence of major cities, due to extraction of groundwater for industrial use, is likely to put the densely populated coastal regions below sea level in less than two decades.

"Our study shows that some parts of Jakarta, and elsewhere in Indonesia, will be below sea level in less than 20 years if they don't stop pumping groundwater," said Rosenstiel School Professor Falk Amelung, a co-author of the study.

...The researchers attributed this rapid land subsidence to groundwater extraction in four major urban areas, including in the capital and largest city of Jakarta (population: 9.5 million), Bandung (population: 2.4 million), Pekalongan (population: 200,000), and Semarang (population: 1.5 million). Indonesia's municipal water supply serves only 25% of its more than 240 million people therefore the majority of the population and industries rely heavily on groundwater extraction for water. Land subsidence from gas field exploitation was also shown to occur near the Indonesian cities of Lhokseumawe and in the Sidoarjo regency.

Unlike Venice, which is sinking at a rate of 2 to 3 millimeters per year, heavily developed regions of Indonesia, including in Jakarta and five other major cities are sinking at rates of tens of centimeters per year.

..."Since these cities are close to sea level and because the subsidence is extremely rapid, the societal impacts could be huge, both in terms of water resources and sinking of the land relative to the ocean," said Chaussard. "Understanding of the processes involved and continuing the monitoring are thus critical for mitigation purposes."....

An aerial view of north Jakarta, shot by Amelia Guo, Wikimedia Commons, under the Creative Commons Attribution 3.0 Unported license