Uncertainties associated with the climate have been a point of challenge in designing and management of water resources systems. Uncertainties such as the effects of global warming on rainfall intensity make it difficult to deterministically design a system’s capacity. While structural fragility curves have been used in other fields as a response to such challenges, this concept has not been standardized in the field of water resources. To help with this shortcoming, this research proposes the use of water resources systems fragility curves as a performance metric to help design sustainable systems. Fragility curves provide more information about the system by considering multiple possible cases, and can complement other concepts such as system reliability, vulnerability, or resilience that are in nature defined for the case of a singular event. To show such concept, this research starts by defining fragility curves within the context of water resources systems. Next, fragility curves are derived for a sample urban flood management system to determine its performance under climate change. At this point, different strategies for reducing system fragility are tested, and their effectiveness is studied by comparing system fragility with traditional metrics such as reliability or resilience. Finally, these test systems are used to identify design procedures, such as principle of de-centralization, that tend to reduce system fragility. Thus, this research uses system fragility as a means of assessing and designing water resources systems by enabling a design that takes into account a wide range of system inputs. Results show that system fragility curves can provide more insight about the inner-workings of the system not captured by the typical performance indicators. In the end, a set of design rules are provided to aid in achieving less fragility in new or existing systems and to help create a more robust infrastructure.
