Jakarta Globe, Ulma Haryanto, Dofa Fasila & Arientha Primanita | February 12, 2011
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Just two months after it reopened following Rp 9 billion ($1 million) worth of repairs, Jalan R.E. Martadinata in Ancol, North Jakarta, is collapsing at several points along its southern section.
Residents said the affected section of road, only a few meters from the Ancol train station, had subsided severely months earlier.
“The road has been like that for a couple of months now,” Beni, 24, a motorcycle taxi driver, told the Jakarta Globe on Friday.
“A week ago some people from the Public Works Ministry came and put up barriers around the collapsed section.”
The road was more severely damaged last September along its northern stretch, 2.5 kilometers from Ancol station, when a 103-meter span consisting of two entire lanes collapsed into the Japat River below.
Authorities blamed the collapse of the 20-year-old road on the erosion of the supporting piles by tidal surges, while urban planners and city councilors believed it was due to weak monitoring and lack of maintenance.
Repairs were carried out by state-owned contractor Wijaya Karya at a cost Rp 9 billion, and the section of road was reopened in December.
When the Globe visited the site on Friday, it could be seen that several sections of Jalan Martadinata had subsided into the river, which runs along the right side of the road.
At least four sections of the road were being shored up by bamboo scaffolding.
Agus, 55, a construction worker who lives and works in the area, said the damage had begun almost a year ago.
“At the time, there was work being done to pave the road,” he said. “The contractors never got around to laying down the concrete before the land suddenly subsided beneath the road.”
Djoko Murjanto, director general of the Public Works Ministry’s Bina Marga unit, which oversees roads, said the cause of the recent collapse was land subsidence in the area.
“We’ve installed sheet piles to support the collapsed sections,” he said.
“We had planned to install them since the collapse of the road last year, however the land subsided faster than we expected.”
He added that an evaluation by the ministry last November had resulted in recommendations to shore up the entire length of Jalan Martadinata with sheet piles.
“Today we’ve done initial measurements for the section that has severely subsided, including other sections that are at risk of collapse, and we’ll install sheet piles along a 100-meter section to reinforce these sections,” Djoko said.
“The old design for the road didn’t call for piles because it was structurally sound, but the soil structure has changed since then, becoming soft and prone to subsidence.”
He said the planned repairs on the critical section were expected to be completed within two months, while repairs to the rest of the road would be completed later this year.
Djoko also said that since September’s collapse, his ministry had been monitoring the overall condition of Jalan Martadinata, one of the main roads for container traffic to Tanjung Priok Port.
“We’ve made a list of where repairs are needed and the points where strengthening of the physical structure is needed,” he said.
“A tender process for the repairs is also under way.”
He added that because the latest subsidence had been unexpected, the ministry would speed up repairs by skipping a tender and appoint a contractor.
“We estimate that it will cost Rp 2 billion,” he said.
Also on Friday, Jakarta Governor Fauzi Bowo said he had ordered the city’s Public Works Office to carry out an investigation into the newly collapsed section of road.
“The road is a national road, which means it falls under the authority of the Public Works Ministry, but we can help by carrying out our own investigation,” he said at City Hall.
He added that much of North Jakarta was prone to land subsidence as a result of massive groundwater extraction, which in turn exacerbated tidal flooding that kept the soil in a continuously soft state and more at risk of further subsidence.
Fauzi said the problem essentially boiled down to the lack of access to clean water in the area.
“As long as the public isn’t served by a good water network, they’ll keep pumping up groundwater,” he said.
“We need to be able to provide sufficient clean water to resolve this issue.”
Parts of North and West Jakarta have experienced some of the worst rates of land subsidence in the city since 1974.
The worst-hit areas are Muara Baru and Ancol, both in North Jakarta, which have sunk by 4.1 meters and 1.88 meters respectively during this time.
In West Jakarta, the land has subsided by up to 2.5 meters in West Cengkareng and 1.97 meters in Daan Mogot.
