25% of Indonesia's Peat Hydrological Units Are Highly Vulnerable to Severe Flooding, These Are the Regions

Research by Pantau Gambut reveals that 25% of Indonesia's peatland hydrological units (KHG), spread across Sumatra, Kalimantan, and Papua, fall into the high flood vulnerability category.

Meanwhile, 18% of KHG areas fall into the moderate vulnerability category, and 57% of areas have a low flood vulnerability level.

“Based on the grouping of KHG distribution, the Kalimantan region recorded the highest flood vulnerability level, followed by Sumatra and Papua,” explained Pantau Gambut in its report The Sinking of Wetlands.

The following are the flood vulnerability levels in KHG areas, according to Pantau Gambut's research in 2025:

Kalimantan

• High vulnerability: 3.82 million hectares (ha)
• Moderate vulnerability: 438,688 ha
• Low vulnerability: 4.05 million ha

Sumatra

• High vulnerability: 1.80 million ha
• Moderate vulnerability: 3 million ha
• Low vulnerability: 4.21 million ha

Papua

• High vulnerability: 303,628 ha
• Moderate vulnerability: 709,332 ha
• Low vulnerability: 5.32 million ha

“The provinces with the highest flood vulnerability are Central Kalimantan, West Kalimantan, South Sumatra, and Riau,” said Pantau Gambut.

In Central Kalimantan, Pantau Gambut explained, peatland degradation due to large-scale plantation activities has altered the landscape of this region. Massive canalization eliminates the peatland's ability to absorb rainwater, leading to more frequent floods.

Pantau Gambut conducted its research using a multi-criteria evaluation (MCE) method with the support of a geospatial information system (GIS). An expert adjustment method was also used to determine each parameter affecting flood runoff.

The data used by Pantau Gambut in its research is periodic data from 2014-2023. One of the data sets used is the annual average rainfall from the Climate Hazards Group InfraRed Precipitation with Station (CHIRPS).