Floods in Mempawah: Accumulation of Deforestation and Land Conversion

06 Feb Floods in Mempawah: Accumulation of Deforestation and Land Conversion

The major flood disaster that hit Mempawah Regency at the beginning of this year was an event that surprised many people. Several areas that had never been affected before were now submerged up to their waists. This phenomenon is not just a result of high rainfall, but also the impact of accumulated deforestation and land conversion that has been going on for years in West Kalimantan.
Over the past two decades, West Kalimantan has lost millions of hectares of primary forest. Based on data from Forest Watch Indonesia (FWI), from 2000 to 2020, West Kalimantan lost more than 1.2 million hectares of forest cover due to the expansion of oil palm plantations, mining, and infrastructure development.
The results of Mongabay Indonesia’s investigation also noted that massive land clearing in upstream areas such as Landak and Sanggau Regencies has worsened the hydrological conditions in downstream areas, including Mempawah. Forests that function as rainwater absorbers have been turned into agricultural land or industrial areas that are unable to hold water runoff naturally.
In addition, river sedimentation due to erosion from upstream areas worsens the situation. Rivers in West Kalimantan, including those flowing into Mempawah, are experiencing shallowing, drastically reducing their water flow capacity. According to a report from the Kalimantan I River Basin Office, sedimentation in the Mempawah River has increased by 40% in the last two decades, causing water to overflow more quickly and flood residential areas.
Mempawah Regency, which is located in the downstream area, is highly dependent on environmental conditions in the upstream area. The loss of forest cover and changes in land use mean that rainwater cannot be properly absorbed in the upstream area. As a result, the volume of water flowing downstream has increased drastically, exacerbating the risk of flooding.
According to a report by WALHI West Kalimantan, around 60% of the water catchment area in the upstream Mempawah River has been converted into monoculture plantations, especially oil palm plantations. This has led to an increase in uncontrolled surface water runoff and increased the risk of flooding.
In addition, many water catchment areas have been converted into residential and industrial areas. Based on data from the West Kalimantan Central Statistics Agency (BPS), the area of ​​non-forest land in Mempawah has increased by 35% in the last ten years, reducing the area’s ability to absorb rainwater naturally.

In addition to deforestation and land conversion, climate change factors are also worsening the situation. The La Niña phenomenon that occurred this year caused higher rainfall than usual. Data from the BMKG Supadio Station shows that the intensity of rainfall in West Kalimantan in the last three months has increased by 200 mm higher than the annual average.
Unfortunately, the inadequate drainage system in the Mempawah area is unable to drain water quickly, causing prolonged flooding. Data from the Mempawah Public Works and Spatial Planning Agency (PUPR) states that more than 70% of drainage channels in urban areas are not functioning optimally due to sedimentation and garbage blockages.
The major flood in Mempawah is an alarm for all parties that environmental governance must be improved immediately. Enforcement of regulations related to deforestation and land conversion needs to be tightened. In addition, rehabilitation of river basins and improvement of drainage infrastructure must be a top priority to reduce the risk of disasters in the future.
If there are no significant changes in environmental management, it is not impossible that disasters like this will recur on a larger scale. It is time for the government, society and private sector to work together to maintain the balance of nature to prevent similar disasters from happening again.

-Teraju Indonesia-