JAKARTA; Jakarta is stepping up flood preparations ahead of the rainy season, but experts warn that the capital remains ill-equipped to cope with heavier rainfall because of inadequate flood-control infrastructure and shrinking green spaces.
The Meteorology, Climatology and Geophysics Agency (BMKG) has forecast more frequent rainfall across the country starting in November as the rainy season sets in. In Jakarta, the rainy season is expected to begin later in December, with rainfall intensity projected to increase and peak in February 2027, raising the risk of flooding.
Urban planning expert Yayat Supriatna said Jakarta no longer had sufficient capacity to absorb heavy rainfall, pointing to shrinking green spaces and unfinished flood-control infrastructure, including drainage wells, reservoirs and river improvements.
“We’re racing against time as the rainy season approaches,” he told The Jakarta Post on Friday. “With only two months left and rainfall already beginning in upstream areas, we must respond with greater vigilance.”
Yayat warned that the city could not rely solely on weather modification operations to divert rainfall. He urged the administration to map flood-prone areas, prepare evacuation and relocation plans, and take steps to prevent casualties.
He also cautioned that flooding could paralyse economic activities, calling for contingency measures including traffic management, remote working and schooling arrangements, regular drainage maintenance and public information campaigns to help residents prepare.
The Jakarta administration has started its mitigation efforts, accelerating river normalisation works since Nov 5 after Governor Pramono Anung convened a meeting with his subordinates to assess the readiness of the city's flood-control infrastructure.
Pramono said the administration would prioritise normalisation works on the Ciliwung, Angke, Krukut and Cakung Lama rivers to improve water flow and reduce flood risks.
The four rivers are among Jakarta’s most prone to overflowing during heavy rainfall and increased runoff from upstream areas in Bogor, West Java, south of the capital.
“From now until December, the Jakarta administration will carry out normalisation works on the rivers [...] and we’ll accelerate the process in the hope that everything will be ready by January, when rainfall is expected to increase ahead of its peak in February,” the governor said in a statement.
The Jakarta Disaster Mitigation Agency (BPBD) has also mapped 200 neighbourhood units (RW) that remain vulnerable to flooding and inundation, and prepared evacuation shelters in potentially affected areas, Antara reported.
The agency said it was prioritising community outreach and environmental clean-up, particularly the clearing of clogged drainage channels. It has also prepared emergency equipment, including rubber boats, evacuation tents, emergency posts, lighting equipment and mobile toilets.
However, environmental group the Indonesian Forum for the Environment’s (Walhi) Jakarta chapter warned that flooding could not be attributed solely to overflowing rivers, making river normalisation alone insufficient to address the city’s recurring problem.
The city instead needed more comprehensive urban planning to preserve land’s capacity to absorb rainwater, said Walhi Jakarta campaigner Muhammad Aminullah.
He estimated that up to 90 per cent of Jakarta’s land had been covered by concrete, leaving limited green spaces to absorb rainfall. He called for better spatial planning to increase permeable surfaces and allow more rainwater to seep into the ground.
More fundamentally, Aminullah said, Jakarta's residents and administration needed to learn to coexist with flooding, which has long been a recurring feature of life in the capital.
“Jakarta has always been a water city, so flooding is always a possibility. What matters is how we prevent it from causing losses and how we learn to live alongside flooding,” he said. - Jakarta Post/ANN
