The public perception of green, hybrid and grey flood protection measures in three European countries

Various flood risk mitigation measures such as green, hybrid and grey measures can be applied to reduce flood risk, which is expected to increase in the future due to climate change. While recent studies on flood risk perception have provided robust empirical evidence of social and regional differences in risk perception, comparative studies on the perception of flood risk management measures are lacking. Across Europe, there are significant differences in the preferred approaches to flood risk management and the identified barriers to their application. As part of this study, we examined the perception of various flood risk management measures in Slovenia, Czechia and the Netherlands. The following concepts were taken into consideration: effectiveness, feasibility and acceptability.

The public perception survey was conducted in the three countries via a self-administered online survey with the support of the external company (Bezak et al., 2024). In all three countries, a representative sample (n = 1000) was taken into account considering spatial and socio-demographic characteristics (quota sample). The selected flood risk management measures were divided into three categories: green, grey and a combination of green and grey (hybrid). The visual appearance (green, grey and hybrid), the extent of ecosystem services provided (zero, substantial and in-between) and the construction effort required (substantial, minimal and medium) were used to classify the measures. During the survey, respondents were only shown the drawing of the measure, not the description or the name of the measure. The following measures were considered: rain garden, wetland, tree trench, retention pond, cistern, dam (Bezak et al., 2024). In addition, three groups of experts were also included in the survey in Slovenia: water engineers, researchers working in the field of water management and agricultural workers.

In terms of individual flood protection measures, respondents (general public) in all three countries tend to view conventional grey measures (i.e., dams and cisterns) as more effective and acceptable, but more difficult to implement. This is in contrast to green and hybrid measures, which are considered feasible but less effective and acceptable. The degree of perceived effectiveness, feasibility and acceptance varies from country to country (Bezak et al., 2024). A similar perception was also noted by three expert groups in Slovenia, where researchers were the only group to consider green measures (i.e., wetlands) more effective than grey measures (i.e., dams). While water engineers and agricultural workers had similar perception as the general public, with water engineers clearly preferring classic flood risk management solutions such as dams. 

While specific projects and initiatives can benefit from knowledge of the individual determinants of flood risk perception, transnational policies and strategies should pay more attention to the specific patterns of perception in individual countries.

 

Reference:

Bezak et al., 2024. Investigating the public perception of green, hybrid and grey flood risk management measures in Europe. Progress in Disaster Science, 23, 100360, 10.1016/j.pdisas.2024.100360.

 

Acknowledgment: The research was conducted within the project [Evaluation of hazard-mitigating hybrid infrastructure under climate change scenarios] co-granted by Slovenian Research Agency (J6-4628) and Czech Science Foundation (22-04520L).