Jabodetabek Floods, How Big is the Threat of Hydrometeorological Disasters in Indonesia?

1. How big is the threat of flooding in Indonesia?
2. Which provinces are prone to disasters and flooding?
3. Why are floods becoming more frequent?
4. How prepared are cities for disasters?

Hydrometeorological disasters are the most frequently occurring natural disasters in Indonesia. Hydrometeorological disasters are caused by weather activities such as the hydrological cycle, rainfall, temperature, wind, and humidity. One form of hydrometeorological disaster is flooding.

In January 2025, there were 302 disasters across Indonesia, 244 of which were floods. The flood disasters resulted in 11 fatalities and displaced 1,189,168 people. Throughout 2024, the National Disaster Management Agency (BNPB) also recorded 3,472 disaster events in Indonesia.

Of that number, 99.34 percent were hydrometeorological disasters. Floods were the most frequent disaster in Indonesia last year. There were 1,420 flood incidents in 2024, followed by forest and land fires (973 disasters), extreme weather (733 disasters), and landslides (207 disasters).

The high frequency of hydrometeorological disasters did not only occur in 2024. Since 2017, hydrometeorological disasters have consistently dominated the types of natural disasters in the country. In 2017, BNPB recorded 2,840 hydrometeorological disasters out of a total of 2,866 disaster events in Indonesia. Not only dominating, but the number of hydrometeorological disaster events has also tended to increase year by year. The number of hydrometeorological disasters in 2018 reached 3,309 events, then increased to 3,777 events (2019), followed by 4,624 events (2020), and 5,365 events (2023).

The high number of hydrometeorological disasters was also accompanied by a significant loss of life and displacement of people. In 2023, flood disasters resulted in 76 fatalities and 3,871,677 people being displaced. Meanwhile, landslides caused 132 deaths and forced 18,775 people to evacuate throughout the occurrences of these disasters in 2023.

West Java, East Java, North Sumatra, South Sumatra, and Central Java are the five provinces with the highest number of disasters throughout 2024. Last year, there were 461 disasters in West Java, followed by East Java (434 disasters) and North Sumatra (350 disasters). Meanwhile, disasters in the Special Capital Region of Jakarta occurred 19 times.

In terms of disaster occurrences, Jakarta has a relatively low number of disasters. However, its topography, situated in a lowland area, makes Jakarta quite vulnerable to flooding. Moreover, there are 13 rivers that flow into the Jakarta area. Based on data from BNPB, in 2023, there were seven instances of flooding in Jakarta.

In contrast to Jakarta, disaster events in West Java tend to be high. Disaster data from 2023 also shows that West Java is the province with the highest number of disasters. Disasters in West Java are dominated by extreme weather, landslides, forest fires and floods. Meanwhile, disasters in Central Java are dominated by forest fires, extreme weather, landslides and floods.

The publication of the 2025 Disaster Risk Index shows that the potential for disasters in West Java is inseparable from its natural landscape in the form of mountains in the central and southern parts, as well as high-intensity rainfall. In addition, West Java also has 40 river basins. There are five areas with high disaster potential in West Java, namely Cianjur, Sukabumi, Tasikmalaya, Karawang. Pangandaran, Garut, and Cirebon.

On a smaller scale, the 2024 Village Potential publication shows natural disasters in villages/sub-districts throughout Indonesia. There are three disasters that occur most frequently in villages. The most frequent are floods experienced by 14,260 villages/sub-districts, followed by earthquakes experienced by 7,158 villages/sub-districts, and landslides experienced by 6,493 villages/sub-districts. The areas that experience the most floods are villages in Aceh, Central Java, West Kalimantan, East Java, and West Java.

Hydrometeorological disasters still have the potential to occur in several regions in Indonesia, including Jabodetabek. One of the triggers for the flood that hit Jabodetabek on March 4, 2025 was extreme rainfall. Extreme weather and weather anomalies are the impacts of climate change and the environment.

Climate change is triggered by increasing greenhouse gas emissions, especially carbon dioxide (CO2) produced by humans. The increasingly extreme weather changes in Indonesia in the last ten years are in line with the trend of natural disasters, especially hydrometeorological disasters which tend to increase.

The high vulnerability due to natural disasters is also inseparable from Indonesia's geographical location. Indonesia's position flanked by two oceans, namely the Indian Ocean and the Pacific Ocean, causes the climate in Indonesia to be very dynamic.

Indonesia also has a maritime climate that is greatly influenced by rapidly changing and highly fluctuating sea surface temperature conditions. Anomalous sea surface temperature conditions in the equatorial Pacific Ocean cause the El Nino and La Nina phenomena. This phenomenon has an impact on the occurrence of various hydrometeorological disasters in Indonesia.

In addition to climate change factors, human activities also worsen environmental conditions. Forest encroachment for plantations, settlements, or development activities that affect the ecosystem and ecology also increase the frequency of disasters. Based on data from the Central Statistics Agency, in the 2019-2020 period, the deforestation rate in Indonesia was recorded at 115,459.8 hectares per year.

According to the Ministry of Environment and Forestry, the total forested land area of Indonesia in 2020 was 95.6 million hectares or 50.9 percent of the total land area. The forested land area of Indonesia has shrunk by 14.3 million hectares or 13 percent in less than two decades. In 2003, the forest area of Indonesia was recorded at least 109.9 million hectares (Kompas, 12/26/2022).

Flooding in Jabodetabek and increasing rainfall intensity in early 2025 are mitigation challenges for cities in Indonesia in facing the threat of urban disasters. Urban development is no longer only oriented towards the economy, but also disaster-resistant cities or resilient cities.

Disaster-resilient cities can be interpreted as cities that are able to anticipate, adapt, and recover from disasters by minimizing the risk of socio-economic and environmental impacts. In Indonesia itself, disaster-resilient city standards have been implemented which refer to SNI ISO 37123:2019. This standardization has regulated the Resilient City Indicator with five main elements in it.

The main elements consist of early warning systems, urban infrastructure, disaster risk management, social and economic resilience, and urban recovery capacity. This standard serves as a guideline in developing urban resilience strategies.

The Jabodetabek regional government and the community must prepare steps to transform into a disaster-resilient city, such as when facing frequent floods. One of the short-term mitigations that has been carried out by the regional government together with BMKG and BNPB is weather engineering to control rainfall. In addition, the regional government must also increase the number of water pumps to control water overflows.

In the long term, macro-scale flood prevention measures are also needed, the benefits of which can reduce flooding in a wider spatial dimension. The construction of giant sea walls, providing more water catchment areas, revitalizing river quality, and building communication with the community to build awareness of disaster risks are an integrated way to deal with flooding. Efforts are also needed to restore the environmental ecosystem in the upstream area as an initial mitigation of flooding. (LITBANG KOMPAS)