Corry Elyda, The Jakarta Post 13 Oct 15;
More than a dozen scientists from institutions in Switzerland, Singapore and Indonesia have collaborated for years to create several models figuring rehabilitation of the Ciliwung River, providing future scenarios that “balance concerns over flooding, water quality and ecology with the reality that a rapidly growing megacity is not a utopia”.
The group’s report was recently issued amid criticism from a school of thought that believes the current Ciliwung “normalization” project carried out by the Public Works and Public Housing Ministry’s Ciliwung-Cisadane Flood Control Office (BBWSCC) is a “traditional and old-fashioned engineering approach”.
The ongoing BBWSCC project is widening the river, constructing concrete embankments and creating a meander cut-off at Kampung Pulo in East Jakarta.
Singapore-based research program Future Cities Laboratory, the Swiss Federal Institute of Technology (ETH Zurich) and Indonesian universities including the University of Indonesia (UI), Bandung Institute of Technology (ITB) and Bogor Agricultural University (IPB) have suggested that other, greener and more innovative, models of Ciliwung rehabilitation are possible.
“Jakarta needs a strong vision for the Ciliwung River as the first public green corridor of cities and regions in its watershed,” the research report said.
Paolo Burlando, the chair of hydrology and water resource management at ETH Zurich, said that the study, which brought together disciplines from engineering, hydrology, landscape architecture and ecology to social sciences, explored how various approaches delivered alternative future scenarios, while taking into account flood mitigation and environmental concerns.
“The project is as much about the reinvention of the river as a brand for Jakarta and West Java — a brand capable of projecting a strong and positive environmental image with sustainable goals, as it is about solving immediate engineering challenges to better manage risk,” he said.
Ciliwung, starting from Mount Gede, meanders 119 kilometers from Bogor through Depok and Jakarta before emptying into the Java Sea.
According to the study, approximately 5 million people reside within the river’s 384 square km catchment.
The study, Burlando said, had reached no definitive conclusion, but offered hypothetical scenarios demonstrating the existence of alternative scenarios to the current project, in which the river is essentially channelized by removing all natural landscape.
“We believe that it is possible to still have a relatively natural river landscape that does not increase the flood risk but eventually reduces [it],” Burlando said on the sidelines of a symposium on the study at Tarumanagara University (Untar).
He added that the BBWSCC’s formula would “only transfer the problem downstream”.
“Closer to the sea, you will have more problems,” he said.
The river’s main challenges include flooding that occurs every rainy season and heavy pollution; Jakarta does not have a wastewater management system and shallow groundwater risks contamination.
According to Burlando, the study shows that while land-use management alone cannot remove the flood risk, maintaining a good forested upper catchment area would help reduce frequency of floods.
The BBWSCC, in collaboration with the Jakarta administration, has evicted 1,040 families in Kampung Pulo and plans to evict more in Bidaracina in East Jakarta and Bukit Duri in South Jakarta to make way for widening and river inspection roads.
Responding to the alternative proposals, Jakarta Water Management Agency head Tri Djoko Sri Margianto said that it was hard to use “green” approaches to flood mitigation.
“River banks are densely populated areas. We need a wider river if the wall is to be natural, which will be difficult for the city administration, as it means we will need to relocate more people,” Tri said.
Another collaboration of architects, planners and hydrologists has proposed creating a kampung susun (elevated village) at Kampung Pulo, in which residents could remain near the meander and take care of the river’s natural embankments.
