An integrated approach for risks and impacts assessment to inform flood risks adaptation in urban regions

Kurzfassung

Exacerbated by climate, socio-economic, political, and environmental change, flood risks are increasing in many parts of the world, often leading to devastating impacts, particularly affecting the most vulnerable. Therefore, enhanced flood risk adaptation is vital to reduce adverse impacts. To best design adaptation measures, comprehensive risk and impact information is crucial as it helps to determine where adaptation is needed, by whom, and why. Unfortunately, this information is often incomplete or even missing. In many cases, this proved to hamper adaptation effectiveness and caused maladaptive outcomes. Therefore, advanced risk and impact assessments considering multiple risks for people, sectors, and systems as well as their underlying drivers are needed to better adapt while leaving no one behind. Based on extensive stakeholder consultations and desk studies as part of the FloodAdaptVN project, we developed an integrated risks and impact assessment concept that was applied in the highly floodprone urban region of Hue, Vietnam. It aims at providing actionable information on flood risks, impacts, and underlying root causes, thereby supporting local agencies in their adaptation efforts. In an initial step, four key impacts were identified by local stakeholders in a co-development workshop in July 2022 in Hue. Fatalities, disrupted agricultural livelihoods, disrupted transportation, and water contamination were rated as most relevant flood impacts for Hue. Second, an impact chain approach has been applied to capture interlinkages within and across these four key impacts and their underlying risks and drivers. Results of the application of this comprehensive flood risks and impact assessment approach in Hue underline the interconnection between risks and impacts and the potential harm of impact cascades. For example, impact linkages were identified between damaged infrastructures (such as damaged or blocked roads and sewerage systems), hampered service provision (such as interrupted water and sanitation supply and interrupted waste collection), subsequent environmental impacts (such as decreased water quality and contamination), health impacts (such as water-borne diseases and injuries), and eventually livelihood impacts (such as disruption of livelihood activities and subsequent income losses). In addition, similar root causes of risk were identified. For example, rapid urbanization proved to increase all subcomponents of risk, namely flood hazard levels (e.g. through increased sealing and subsequent increase of runoff), exposure (e.g. through increased number of people, physical assets and economic activities, often in flood prone areas), and vulnerability (e.g. through increased marginalization). The identification of cross-sectoral, interconnected risks and impacts helps to avoid blind spots and maladaptive outcomes when designing adaptation measures. It also helps to identify entry points for interventions that can tackle multiple underlying risk factors and thereby avoid direct and cascading impacts. For example, enhanced risk-informed urban planning could help to reduce urban flood hazard, exposure, and vulnerability levels, thereby contributing to effective adaptation to urban flood risks. This presentation will discuss results of the applied risks and impact assessment for Hue in more depth. In addition, insights into the development of the applied integrated risks and impact assessment approach as well its potential for transferability to other risk-prone urban areas will be provided.