Unveiling transboundary challenges in river flood risk management: learning from the Ciliwung River basin

To cope with massive development, many urban and surrounding rural areas have been agglomerated into a greater metropolitan area, aiming for regional economic development. Many of these metropolitan areas have experienced a dramatic increase in impacted area and economic loss from annual flooding. The issues and challenges emerging from transboundary river flood risk management have become a major concern for the Jakarta metropolitan area with a long river basin crossing several administrative jurisdictions. Previous studies have addressed the challenges of flood risk, but they have tended to overlook transboundary issues and power sharing. To tackle future flood events, this paper aims to unveil transboundary challenges and power sharing in flood management, learning from Ciliwung River. As the longest river basin crossing cities and regencies of Greater Jakarta, the complexity of Ciliwung flood risk management was driven by flood variables triggered not only by natural, physical, and socioeconomic factors, but also by transboundary challenges and power sharing. A total of 13 significant transboundary flood drivers were identified from the literature, policy, and practices. Using Matrice d'Impacts Croisés Multiplication Appliquée á un Classement (MICMAC), a power–dependency model, several strategic key flood drivers were further recognized based on key stakeholders' perspectives obtained from in-depth interviews and focus group discussions (FGDs). Findings of the study show that a lack of control of spatial plans and weak stakeholder coordination–cooperation are found to be the priority key flood drivers for risk reduction intervention. Finally, this study contributes to the literature on governance of flood risk management by emphasizing the need for a coordinated and integrated approach to mitigate flood risks that extend beyond administrative boundaries, enhancing overall resilience and sustainability.