Emergency measures, such as sandbags, are often used during flood events to prevent breaches in flood defences. However, there is limited insight into their contribution to flood prevention. This paper describes a method to determine the reliability of a system of flood defences including emergency measures. The reliability of the emergency measure depends on the completion of three events: 'Detection' , 'placement' and 'construction' . Both detection and placement can fail due to human error or insufficient time; construction can fail due to structural failure. The method was applied to a case study in the Netherlands, in which the reliability of a flood defence system including emergency measures was determined. We found that emergency measures can increase the reliability with a factor 1.5-4, depending on the considered failure mode of the dike. Failure of detection and placement, and the underlying human reliability, had the highest contribution to the failure probability. Emergency measures proved to be cost effective, but are still less cost effective as traditional reinforcements. They could play a role as an interim solution to reduce flood risk.

The application of risk‐based approaches for the design of flood infrastructure has become increasingly common in flood management. This approach, based on risk reduction and reliability, is used to assess the performance of conventional interventions (e.g., flood defences and dams) and to support decisions regarding their implementation. However, for more innovative solutions, performance has often not been quantified by means of these metrics and, therefore, end‐users are hesitant to implement them in existing flood risk reduction systems. To overcome the gap between innovators and end‐users, we present a framework based on four performance indicators, to ensure the required insights in risk and reliability are provided. The four indicators: effectiveness, durability, reliability and costs, allow end‐users to evaluate, select, and implement flood adaptation innovations, and provide innovators with insight into the performance of the technology and the criteria and information necessary for successful market uptake of their innovation. The practical application of the framework is demonstrated for a (hypothetical) case of a hospital complex built in an area that has subsided below the surrounding area, which is subject to tropical rain showers. The following innovations are considered: an early flood warning system, a green roof, and a temporary flood barrier.

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