Jakarta faces real, immediate threat of sinking<\/p>\n
Berni K. Moestafa, The Jakarta Post, Jakarta<\/p>\n
A major increase in construction, overexploitation of
\ngroundwater and unstable soil are causing parts of Jakarta to
\nsubside by up to eight centimeters a year, making the capital
\nprone to more flooding, a surveyor company's report said.<\/p>\n
A joint report by the city administration and state-owned
\nsurveyor firm PT Sucofindo predicted that from 1999 to 2005
\nJakarta would sink at a rate of between 1.5 centimeters and eight
\ncentimeters a year.<\/p>\n
During that period, North Jakarta may sink between two
\ncentimeters and eight centimeters, West Jakarta by 2.2
\ncentimeters, East Jakarta by 1.5 to three centimeters, and South
\nJakarta by two centimeters.<\/p>\n
\"Lower land means there is an increased possibility that
\nflooding will worsen,\" said the president of PT Sucofindo
\nAppraisal Utama, Ganis Ramadhani, on Wednesday.<\/p>\n
Sucofindo Appraisal is a subsidiary of Sucofindo. It conducted
\nthe study under the order of the city administration, which,
\naccording to one company official, wanted scientific proof that
\nland was subsiding.<\/p>\n
The study will help better anticipate flood problems and
\nprovide developers with data on the extent of land subsidence
\naround the city.<\/p>\n
Jakarta saw its worst floods in over 50 years last January. At
\nleast 30 people were killed and 15 more died from flood-related
\ndiseases, while thousands were forced to seek shelter for several
\nweeks.<\/p>\n
The city administration took the blame for failing to
\nanticipate the magnitude of the flood, as well as developers for
\nbuilding houses in water catchment areas.<\/p>\n
Parts of the city, however, have sunk by four centimeters to
\n91 centimeters over the past six years, according to one report
\nby the City Mining Agency.<\/p>\n
Ganis said land had subsided because of pressure on loose
\nsoil. The construction of houses and buildings have accelerated
\nthe sinking process.<\/p>\n
Another contributing factor has been the exploitation of
\ngroundwater.<\/p>\n
Water drawn from underground sources has loosened the soil,
\nand along with the weight of construction, has caused land to
\nsubside until it becomes dense again, Ganis explained.<\/p>\n
Groundwater accounts for 56 percent of the clean water Jakarta
\nconsumes, while rivers supply the rest through the city water
\ncompany PAM Jaya.<\/p>\n
Regulations on groundwater use exist, but only 7.5 percent of
\nthe water Jakarta draws from wells is regulated, said the head of
\nthe City Mining Agency, Muzahiem Mochtar.<\/p>\n
He suggested that the city administration increase the tax
\nrate for using groundwater to prevent people from wasting it.<\/p>\n
But the exploitation of groundwater accounts for only 19
\npercent of land subsidence, he added.<\/p>\n
Eighty percent is due to the weight of manmade structures, and
\none percent is because of natural processes.<\/p>\n
While the impact was mainly from construction, Ganis said it
\nalso depended on whether engineers had factored in the risk of
\nland subsidence.<\/p>\n
Office buildings in Jakarta's business district on Jl. Jend.
\nSudirman and Jl. MH. Thamrin should be relatively safe, he said.<\/p>\n
\"It's usually tall office buildings and luxury homes that have
\nanticipated the risk of land subsidence,\" said Agusman Effendi,
\nthe chairman of the Indonesian Real Estate Association (REI).<\/p>\n
In that case, he explained, subsiding land would cause
\nbuildings to sink into the ground, but not collapse.<\/p>\n
Agusman said developers should have had access to information
\non land subsidence prior to beginning their projects.<\/p>\n
However, the city's 2010 master plan excluded geological
\nfactors.<\/p>\n
Chairman of the Urban and Regional Development Institute,
\nWicaksono Sarosa, said he did not see any information related to
\nland subsidence in the city's planning.<\/p>\n
\"The information should have been there (during city
\nplanning), but I guess it could be added later on,\" he said.<\/p>\n
Wicaksono said developers should know the weight capacity of
\nthe land they plan to build on.<\/p>\n
Ganis said Sucofindo's findings were incomplete and further
\nmeasures would provide a more accurate picture of the extent of
\nthe problem.<\/p>\n
\"This is a preliminary study and we see opportunities for more
\n(studies) in the future. They will be ongoing,\" he said.<\/p>",
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