Interactions Between Public and Private Flood Adaptation: Insights From a Socio-Hydrological Model

Flood damages result from interacting hydrological and social processes. System-dynamics models can describe these interactions numerically, generating insights into possible future impacts. In this work, a model is developed based on 3,770 household survey responses on flood risk perceptions and management from various locations in Austria. The model represents the empirically observed coupled-interactions between household flood damages, public measures at the community level that reduce exposure to flooding, and private measures at the household level that reduce vulnerability to floods. Model outputs show how climate change, that may lead to larger floods occurring sooner in the future, would incur costs at an earlier point in time. These costs come from both the flood damages that occur before proactive measures have had time to be implemented, as well as the reactive investments after flooding that occur sooner than without climate change. Continual and increased proactive investments in public measures minimize future damages. However, because they might meet financial, technical or social limitations, private household measures could step in to reduce vulnerability. Flood experience increases household measures (e.g., preparedness plans). Modeling shows how these reduce vulnerability shortly after flooding. This is particularly valuable in the time-period before public measures that reduce exposure have been implemented. However, household measures decay rapidly, suggesting the need to promote their implementation (ideally prior to flooding), and ensure their continual functioning through support for their operation and maintenance at the household level, in the same way that it is considered at the public level.