Transboundary Collaborative Modeling: Consensual Identification and Ranking of Flood Adaptation Measures—A Case Study in the Mono River Basin, Benin, and Togo

Abstract

The field of environmental management, specifically flood risk management (FRM), emphasizes participatory decision-making to address diverse issues and conflicting interests among stakeholders. This approach recognizes the complexity of decisions and their long-term impact on sustainability. Collaborative knowledge production is crucial for understanding the system, generating scenarios, and establishing consensus on mitigation and adaptation measures. Transboundary FRM requires an interdisciplinary and transdisciplinary approach, employing suitable tools and methods for assessment and decision-making. In the context of the CLIMAFRI project, funded by the German Federal Ministry of Education and Research (BMBF), we evaluated the practicality of a participatory Collaborative Modeling framework in the transboundary Lower Mono River (LMR) basin, shared by Togo and Benin. This framework enables holistic understanding, stakeholder engagement, and the identification of appropriate adaptation-mitigation measures based on predefined evaluation criteria and a Multi-Criteria Decision Method. Our study customized and evaluated the framework considering the impact of the COVID-19 pandemic, which restricted face-to-face interactions. The study’s results indicate that in both countries, FRM is characterized as being more proactive rather than preventive, meaning the actions taken mainly address a broader range of potential issues and opportunities rather than targeting specific risks to minimize their impact. Moreover, it is crucial to enhance preventive measures and further improve the flood assessment capacity. The information obtained from scenarios involving the Adjarala Dam, land-use, and climate change under RCP 4.5 and 8.5 scenarios for the years 2030, 2050, and 2100 is valuable for decision-making regarding the development and prioritization of adaptation measures. The ranking of the seven measures shows that capacity building is the most preferred, followed by dykes, early warning systems, regulation of land use, insurance, and retention zones. The group ranking of Togo and Benin highlights differences in their perceptions and interests, where Togo leans towards soft measures, while Benin prefers hard (physical) measures.