Performance Assessment of Water Distribution Systems Subject to Leakage and Temporal Variability of Water Demand

A water distribution system (WDS) is designed and managed to provide a reliable water supply, that is, to properly respond to water user demand, particularly in critical operating conditions such as in times of peak demand. Therefore, the assessment of the influence of water demand characteristics is an essential requirement in the context of WDS reliability. In this paper the impact of the pattern of hourly demand on WDS performance is analyzed for a system subject to aging processes and temporary pipe unavailability and affected by water losses with different leakage levels. The hydraulic deficit that can occur when the pressure falls below the minimum service value is used as a performance index, and its relevance is analyzed without and with preventive maintenance. The case of the synthetic Anytown network is analyzed, but the procedure has general validity and can be applied to any real WDS. Defined in a prescribed temporal horizon the pipe replacement prioritization without preventive maintenance, the effects of pipe substitutions are analysed as a function of different scheduling times to quantify the reduction of the hydraulic deficit. The results show the capability of the proposed approach to define a pipe replacement prioritization and the related scheduling time, in view of the relevance that these aspects could have in any economic analysis developed to define a proper maintenance strategy.