Ketapang City

The province of West Kalimantan is one of the most flood-affected regions of Indonesia, with almost 1 in 2 people exposed to significant flood risk, double the national average of 1 in 4. Ketapang in West Kalimantan is one of the province’s worst affected districts.

KETAPANG CITY

In October 2022, the sub-districts of Jelai Hulu, Manis Mata, Nanga Tayap, and Delta Pawan (the latter more commonly known as Ketapang City) suffered from severe flooding.

Even in July 2023, when Indonesia was entering an El Nino dry season and fires were being detected on agricultural and forestry plantations, the sub-district of Jelai Hulu was experiencing floods as high as 2.5 metres.

Flooding particularly affects its capital city, Ketapang City. Serving as the administrative centre of Ketapang district and home to approximately 92,000 people, this coastal city is only 1-4m above sea level and floods regularly. The Pawan River, which runs through the province of West Kalimantan, ends in the South Chinese Sea close to Ketapang city. This river has a length of 197 km and a catchment mostly composed of forested peatlands and oil palm plantations.

To gain a better understanding of the causes of Ketapang city’s floods, Sangga Bumi Lestari and AidEnvironment recently supervised a group of students from Wageningen University to conduct a scoping study to identify the likely causes of the floods. Their desk research included spatial and hydrological mapping and identified the three most likely significant factors:

Soil alteration by land use change, mainly alteration of forests and peatlands, and soil sealing. This has been driven by the expansion of oil palm and industrial forest plantations in the Pawan river watershed.
Inadequate drainage systems. The drainage in the city is made up of open-air canals that often also serve as sources of irrigation for the nearby croplands. These drainage systems are often clogged, not connected well enough, not maintained, and full of sediments and are leading to increased flooding.
Alteration of river morphology. River sediment input and erosion from marine currents have changed the morphology of the river and its meanders, reducing its ability to slow down and displace water in the vicinity of Ketapang city.

In September 2023, Sangga Bumi Lestari began a project to further investigate the causes of flooding in Ketapang city and develop suitable strategies for how they can be mitigated. The project will include hydrological modelling of the Ketapang watershed, spatial analysis and focused discussions with key landscape stakeholders, the development of possible interventions and a full social and economic analysis of their viability, and strong engagement with the local government to socialise the results of the analysis and the possible mitigation strategies.