Today
Jakarta
- 28 °C
Other Publications
Developers urged to help prevent floods
Tifa Asrianti , The Jakarta Post , Jakarta | Mon, 09/29/2008 10:54 AM | City
The floods that hit Jakarta each rainy season could be reduced if property developers applied appropriate water management strategies in their developments, experts say.
Developers tend to protect their properties from flooding by elevating the land surface, said Indratmo Soekarno, a water resources expert at Bandung Institute of Technology.
But while this might keep their land flood-free, the rainwater pours onto neighboring areas, usually inhabited by poor communities, he said.
"Developers should maintain water basins so they can hold rainwater inside the building complex during heavy rains. They can then gradually release the water into the city's drainage system after the flood level outside the area has dropped," Indratmo said.
The current lack of water basins is a contributor to the city's floods, with most developers removing existing water basins and green zones before building, he said.
Development projects that have been criticized for this are Pantai Indah Kapuk housing complex (previously a mangrove forest), Mega Mal Pluit (formerly part of Pluit Dam) and Taman Anggrek Mall (previously Tomang urban forest).
Furthermore, Indratmo said, residential complexes should make rainwater seepage pits to ensure zero overflow. The pits would enable one house to hold between eight and 10 cubic meters of water that fell onto its lawn.
Wisnu Subagya Yusuf, head of the public works agency, said the governor had instructed all building owners to make these pits so water would not flow straight into the rivers.
"We aim to have zero overflow by raising the water absorption ratio from 2.9 percent to 4.9 percent by 2010," he said.
For better water catchment, Indratmo said, the city administration should build polders and pump the water into the ocean later. He said that in developed countries, the pump automatically drained the polder if the water level reached a certain height.
"The polder and pump system require only a small investment, but they have to be regularly maintained and dredged," he said.
Wisnu said Jakarta already had a 30 percent area for the polder system and would build more polders in the future.
Jakarta has been experiencing flooding since the Dutch colonial era because the 13 rivers running through the city cannot manage the flow of water, Indratmo said.
"Instead of building new canals, the administration should focus on dredging the 13 rivers regularly. Even the East Flood Canal, which needs Rp 150 trillion for construction, will need at least 1 percent of that cost for maintenance. Otherwise the canal will be filled with sediment," he said.
