A screening method to identify promising performance improvements of storm surge barriers

Abstract

Storm surge barriers are critical structures in coastal flood defences that operate only during expected storm surge events. Rising sea levels increase flood risk and intensify the need to improve barrier reliability. At present, reliability analysis supports risk reduction by identifying, quantifying, and prioritising failure scenarios. However, this scenario-driven approach can overlook effective performance improvements, given the wide range of potential measures that differ in scale and type. This study introduces a checklist of 85 candidate performance improvements, organised into eight categories, and proposes a novel screening method with three stages: (1) importance analysis to eliminate negligible improvements, (2) expert judgement to discard unpromising options, and (3) expert ranking of the remaining candidates. The method was applied to the Maeslant Barrier (Rotterdam, the Netherlands), yielding a ranked top-five set of improvements. The case study demonstrates that current practices are particularly poor at identifying low-cost improvements above the component level with little organisational burden. Although the proposed checklist and screening method are more comprehensive and structured than current approaches, additional case studies are needed to validate the method and assess its broader applicability to storm-surge barriers and other safety-critical infrastructure systems.