Vulnerability Assessment of Drinking Water Distribution Networks to Chemical and Biological Contaminations: Case Study

Abstract

Drinking water distribution networks (DWDNs) are vital urban infrastructures. These systems are susceptible to widespread contamination. It is necessary to provide a minimum level of performance for DWDNs by decreasing their vulnerability to contamination. In this paper, a framework is proposed for the evaluation of DWDN response to biological and chemical contaminants. A simulation model is developed for analysis of a DWDN in the eastern part of Tehran, Iran. Various scenarios are defined based on type of contaminants, reactions with chlorine, contaminants’ dose and injection duration, and chlorine initial concentration to see how the network would respond to the spread of contamination. Based on the network’s ability to provide demand with acceptable quality, an index is suggested for vulnerability assessment. To mitigate the network’s vulnerability, chlorine injection and pipe closures are suggested. Results show that the proposed index can be used for identifying the DWDN critical nodes and for comparison of network performance in different scenarios. The results also indicate the key role of residual chlorine in contaminant decay and in assessing DWDN response to widespread contamination.