Post-disaster sequential recovery planning for water distribution systems using topological and hydraulic metrics

Multiple pipeline failures in water distribution systems (WDS) caused by natural hazards such as earthquakes can significantly reduce the functionality of the systems. After a natural disaster, a quick recovery of WDS is desirable to ensure that critical facilities have access to clean water. However, experience from recent disasters has shown that the recovery period for WDS can be long. The recovery period depends on various factors, such as available resources, budget, etc. As such, all the failed pipelines cannot be repaired at the same time. Hence, utilities need to prioritise damaged pipelines and perform the repair in such a way that the functionality of the WDS is optimised. Post-event system functionality gain may vary significantly depending on the choice of sequential recovery paths. Unlike other infrastructures, the functionality of WDS is not only dependent on topological integrity but also on hydraulic performance. In this study, a post-disaster recovery planning model for WDS is proposed. The restoration process is modelled in terms of topological efficiency, hydraulic resilience and hydraulic availability. The optimal recovery sequence is determined based on the recovery effectiveness estimated by the area under each recovery sequence curves. The proposed method is illustrated for a moderate size WDS.