JAKARTA – Jakarta’s flooding is not solely the result of heavy rainfall, but rather a recurring structural problem that has yet to be addressed in a sustainable manner.

Heavy rain that drenched Jakarta and its surrounding areas from Thursday (22/1/2026) to Saturday (24/1/2026) caused hundreds of neighborhood units (RT) to be inundated, dozens of roads to be paralyzed, and even resulted in fatalities.

Although rainfall intensity was the immediate trigger, observers believe that Jakarta’s flooding is an accumulation of urban planning, spatial planning, water management, and climate change issues that have long tended to be neglected.

Urban Planning observer from Universitas Indonesia, M. Aziz Muslim, emphasized that Jakarta’s flooding must be viewed from a historical and structural perspective.

“Flooding in Jakarta is essentially a recurring structural and cultural problem because it has not been handled in a sustainable way,” Aziz said in an interview with Kompas.com on Tuesday (27/1/2026).

According to Aziz, since the Dutch colonial era, Jakarta has indeed faced flooding problems.

Jakarta’s geographical condition, which lies in lowland areas and is even partly below sea level, makes the city naturally prone to inundation.

In addition, Jakarta is the estuary of at least 13 major rivers originating from Bogor, Depok, and surrounding areas.

When extreme rainfall occurs, both in upstream regions and in Jakarta itself, the capacity of rivers and urban drainage systems is quickly exceeded.

“As we saw recently, extreme rainfall clearly exceeded drainage capacity. Coupled with tidal flooding in the coastal areas of North Jakarta, this worsened the situation because the water could no longer be accommodated,” Aziz said.

Unintegrated Spatial Planning

Aziz assessed that the flooding problem has become more complex because Jakarta’s spatial planning is not integrated with water management and infrastructure.

Massive land-use conversion, especially in water catchment areas, has become one of the main factors increasing flood risk.

Green open spaces are increasingly shrinking, while densely populated settlements along riverbanks narrow river channels.

“The soil’s ability to absorb water becomes very limited. Riverbanks are shallow and narrowed, while green areas continue to decrease,” he said.

This condition is exacerbated by poorly maintained drainage infrastructure. Many water channels are clogged by garbage and sedimentation, causing them to fail to function optimally during heavy rainfall.

In the short to medium term, Aziz encouraged the optimization of existing infrastructure, such as the Ciliwung diversion channel, dams, floodgates, and pump systems.

However, he also stressed the need for new breakthroughs.

One alternative that needs to be seriously studied is the construction of underground water tunnels (underground reservoirs) with dual functions.

“Major cities like Tokyo and Kuala Lumpur have already implemented this system. Under normal conditions it can serve as traffic access, but during floods it can function as an emergency water channel,” Aziz explained.

However, he warned that the construction of such infrastructure must go through careful study and cannot be carried out hastily.

Culture and Leadership

In addition to structural aspects, Aziz also highlighted the cultural aspects of society.

The massive use of groundwater by households and industries accelerates land subsidence, which ultimately increases flood risk.

“Public awareness in using water and disposing of waste is still an issue. This is a cultural problem that must be addressed,” Aziz said.

Aziz emphasized that the leadership of local governments is crucial.

He believes that flood management must be a priority agenda designed sustainably, not something that only emerges during the rainy season.

“So far, there has been a tendency that during the dry season, the flood issue is forgotten. In fact, that is precisely when planning should be carried out,” he said.

Unusual Extreme Weather

From a meteorological perspective, BMKG recorded that the rainfall occurring in Jakarta in January 2026 was classified as extreme compared to historical averages.

The Head of the Weather Prediction and Early Warning Working Team at BMKG, Ida Pramuwardani, explained that the increase in rainfall was triggered by the active Asian Monsoon accompanied by the strengthening of the Cold Surge index and the Cross-Equatorial Northerly Surge (CENS).

“This condition indicates the flow of moist air masses from Asia meeting air masses from the southern hemisphere, forming convergence clouds in the Intertropical Convergence Zone (ITCZ),” Ida said.

These cloud patterns stretched extensively from the Indian Ocean west of Sumatra to eastern Indonesia, including Java and Jakarta.

BMKG Deputy for Climatology, Dr. Ardhasena Sopaheluwakan, stated that observational data from several BMKG stations showed that rainfall during the second ten-day period of January 2026 was far above normal and classified as extreme.

“At Kemayoran Station, 412.5 mm was recorded; Tanjung Priok, 529.5 mm; and Cengkareng, 347.2 mm. These figures are the highest since 1991 for the same ten-day period,” Ardhasena said.

BMKG also recorded daily rainfall in the heavy to extreme category on 18 and 23 January 2026, with several areas recording rainfall above 200 mm per day.

BMKG emphasized that Jakarta is experiencing significant changes in rainfall patterns due to climate change.

Rain now tends to fall over shorter durations but with very high intensity.

“This type of rainfall is very dangerous for Jakarta because the soil and drainage systems do not have enough time to absorb or channel the water,” Ardhasena explained.

Historical analysis over more than 100 years shows an increase in the frequency of extreme rainfall and flooding over the past three decades. Flood risk in the modern climate era is estimated to have increased two to three times compared to the past.

Risk and Land Subsidence

Senior Researcher at the BRIN Research Center for Limnology and Water Resources, Dr. Yus Budiyono, assessed that Jakarta’s flood risk continues to increase, particularly due to land subsidence.

“The risk of flood losses due to land subsidence has increased significantly, from around 126 million US dollars per year to 421 million US dollars per year,” Yus said when contacted.

According to him, attention to West Jakarta has increased because the area is heavily influenced by the Angke Pesanggrahan and Mookervaart systems, which previously received less attention compared to the Ciliwung.

In the short term, Yus believes that area management through smaller polder systems is the most strategic step, especially in West Jakarta.

“In the 2030 Spatial Plan and Regional Regulation Number 1 of 2012, North Jakarta is planned to be divided into 66 polder systems. This plan needs to be realized immediately,” Yus said.

Each polder should ideally be equipped with retention ponds or lakes as well as pump systems to channel water into main rivers.

With smaller polders, management is considered easier and technical implementation more realistic.

In the long term, Yus emphasized the importance of a living with water approach.

Given that parts of Jakarta lie below sea level, strategies to completely keep water away are considered unrealistic.

“We must learn to live side by side with water, especially during the rainy season,” he said.

In addition, the maintenance of urban drainage systems must be adjusted to adequate return period standards and kept free from garbage and sedimentation.

Source: https://megapolitan.kompas.com/read/2026/01/29/11594851/banjir-jakarta-bukan-sekadar-hujan-tapi-masalah-struktural-yang-terus