Following a flood the functioning of critical infrastructure (CI), such as power and transportation networks, plays an important role in recovery and the resilience of the city. Previous research investigated resilience indicators, however, there is no method in the literature to quantify the resilience of CI to flooding specifically or to quantify the effect of measures. This new method to quantify CI resilience to flooding proposes an expected annual disruption (EADIS) metric and curve of disruption versus likelihood. The units used for the EADIS metric for disruption are in terms of people affected over time (person × days). Using flood modelling outputs, spatial infrastructure, and population data as inputs, this metric is used to benchmark CI resilience to flooding and test the improvement with resilience enhancing measures. These measures are focused on the resilience aspects robustness, redundancy and flexibility. Relative improvements in resilience were quantified for a case study area in Toronto, Canada and it was found that redundancy, flexibility, and robustness measures resulted in 44, 30, and 48% reductions in EADIS respectively. While there are limitations, results suggest that this method can effectively quantify CI resilience to flooding and quantify relative improvements with resilience enhancing measures for cities.

Gersonius, B., A. van Buuren, M. Zethof, and E. Kelder. 2016. Resilient flood risk strategies: institutional preconditions for implementation. Ecology and Society 21(4):28. https://doi.org/10.5751/ES-08752-210428

There is a growing international recognition that flood risk management in optima forma should be a programmed and flexible process of continuously improving management practices by active learning about the outcome of earlier and ongoing interventions and drivers of change. In the Netherlands, such a long-term, adaptive flood risk management strategy is now being implemented. This so-called second Delta Programme aims to identify and exploit opportunities and capitalize on short-term benefits and opportunistic synergies that arise from change and will require adaptive policymaking. It also requires the financial and institutional means to operate in a long-lasting way, which at the very least, means engaging stakeholders, gathering and disseminating results and adaptation of future plans. Transferring the Dutch approach to other countries is a major challenge that calls for fundamental changes in institutional arrangements at various levels and thus requires customized programmes for strategic institutional change. Recent examples of transfer will provide important lessons of how institutional change can successfully occur and will contribute insights for other countries that attempting to reform their flood risk management strategies. Continuous monitoring and evaluation and sharing international experiences will become crucial for the effective delivery and wider uptake of these new strategies around the globe.