Disaster mitigation expert and Professor of Geological and Environmental Engineering at Universitas Gadjah Mada (UGM), Professor Dwikorita Karnawati, stated that landslides and subsequent flash floods in Aceh, North Sumatra, and West Sumatra remain highly likely, particularly as the rainy season continues.
“One urgent mitigation measure that must be carried out immediately is reducing the risk of further flash floods,” she said on Tuesday (Dec. 23).
According to her, this can be achieved through comprehensive inspections in upstream watershed areas, particularly to examine remaining landslide deposits, debris, and logs still trapped on slopes or within river channels at higher elevations.
These deposits have the potential to block river flow during or after heavy rainfall.
“If these natural blockages collapse, they can trigger flash floods downstream and in lowland areas, increasing the risk of casualties and damaging infrastructure that is under construction or already in place,” she explained.
In addition to inspections and assessments, immediate mitigation efforts should also include controlled diversion or channeling of sediment blockages in upstream river channels toward downstream areas to prevent them from developing into flash floods.
“In the medium term, a series of check dams must be constructed from upstream areas down to mountain foothills to regulate the speed and volume of sediment flowing downstream, thereby minimizing the destructive force of flash flood sediment flows,” she added.
Meanwhile, sediment, mud, logs, and animal carcasses must be removed from land and vital infrastructure, such as roads, irrigation channels, and houses, as soon as possible.
This step is essential so that facilities that remain viable can be reactivated promptly, at least as temporary shelters and infrastructure, while awaiting the provision of permanent housing during the rehabilitation and reconstruction phase.
During the rehabilitation and reconstruction stage, a comprehensive evaluation and remapping of future hazard zones, along with the current level of environmental damage, must be undertaken.
Disaster mechanisms and causes should be examined through direct field fact-finding, followed by simulations using validated, verified physical–mathematical models based on empirical data.
In the rehabilitation and reconstruction process, the active involvement of local governments and all regional stakeholders, including volunteers, non-governmental organizations (NGOs), the private sector, academics, and local communities not directly affected, must be optimized.
This engagement should be carried out through intensive dialogue, strengthened understanding of local wisdom and knowledge, and direct participation in rehabilitation and reconstruction activities.
“Such a participatory approach is crucial to ensure the effectiveness and relevance of recovery efforts, so that the housing and infrastructure built truly reflect local needs, social conditions, and cultural traditions,” she said.
Given the vast affected areas and the complexity of rehabilitation and reconstruction challenges that must be addressed swiftly and accurately, Professor Karnawati proposed the establishment of a special body dedicated to restoring post-disaster living conditions and livelihoods in West Sumatra, North Sumatra, and Aceh.
This institutional model could draw lessons from the Aceh Rehabilitation and Reconstruction Agency, formed after the 2004 tsunami, which featured strong leadership and was supported by agile, tactical, and experienced human resources with proven capacity to manage major disasters across Indonesia.
Author: Salwa
Editor: Gusti Grehenson
Post-editor: Salma
Photograph: Antara