The benefits of flood mitigation strategies: effectiveness of integrated protection measures

Given the investments that local, regional, and national governments have already made in mitigation and may consider in the future, it is crucial to assess mitigation effectiveness across all scales and determine which strategies are the most appropriate. This is particularly relevant as mitigation is viewed increasingly as a vital action for which investments and the resulting benefits must be evaluated and justified. It is fundamental to determine which measures are the most effective in optimising the response to floods in local communities. The study analyses the current state of knowledge on flood mitigation and reviews what methodologies have been applied in order to assess mitigation effectiveness and positive cost-benefit ratio (CBR). The growing body of literature has shown that losses from natural hazards can be significantly reduced when one or more mitigation techniques are put into practice. Moreover, an effective response to floods requires the contribution of flood-prone households and their local community, known as the bottom-up approach, in order to apply risk management strategies to increase community resilience. The results demonstrate that effectiveness increases when integrated approaches are implemented. In particular, the combination of top-down and bottom-up solutions can provide the best results in terms of socio-economic assessments. The study found that the commitment of both public and private stakeholders was of vital importance in achieving good flood mitigation levels, thus, mitigation must be seen as a joint effort between these actors. The paper also provides key findings from literature and recommendations for further research.