The condition of flood defence revetments is influenced by many different degradation processes such as animal burrowing, rutting and growth of weeds. Many of these processes are shock-based rather than progressive continuous. As shocks can cause a drop in performance, this means that the condition of a revetment can suddenly decrease, meaning that revetments can have significant initial damage at the beginning of a storm. Combined with the limited detection probability of common visual inspections of flood defences, this can have a significant influence on the reliability of flood defence systems, something typically not considered in reliability analysis. In this paper we study the reliability of a flood defence system subject to shock-based degradation. Various maintenance concepts are compared for a case study of a riverine flood defence of 20 kilometres length. This demonstrates that the current maintenance concept is insufficient to satisfy the reliability requirements for failure of the revetment. Overall, the joint influence of degradation and the existing maintenance concept leads to a 20 times higher failure probability estimate compared to a typical assessment without these aspects. Next, we demonstrate that both additional inspections, and targeted interventions to reduce the impact of for instance animal burrowing, can significantly reduce total cost and improve robustness of the considered flood defence system.

防洪护岸的状况受到许多不同退化过程的影响，例如动物挖洞、车辙和杂草生长。其中许多过程是基于冲击的，而不是渐进的、连续的。由于冲击可能导致性能下降，这意味着护岸的状况可能会突然下降，这意味着护岸在风暴开始时可能会受到严重的初始损坏。再加上防洪常见目视检查的检测概率有限，这可能会对防洪系统的可靠性产生重大影响，而可靠性分析中通常不考虑这一点。在本文中，我们研究了受冲击退化影响的防洪系统的可靠性。以20公里长的河道防洪工程为例，对各种维护理念进行了比较。这表明目前的维护理念不足以满足护岸失效的可靠性要求。总体而言，与没有这些方面的典型评估相比，退化和现有维护概念的共同影响导致故障概率估计高出 20 倍。接下来，我们证明，额外的检查和有针对性的干预措施以减少动物挖洞等的影响，可以显着降低总成本并提高所考虑的防洪系统的稳健性。