Improving Resiliency of Water Supply System in Arid Regions: Integrating Centrality and Hydraulic Vulnerability

Abstract

A water supply system is a key infrastructure providing critical services to city-dwellers. Due to major disaster events causing a water shortage, the supply systems can be vulnerable. This paper presents a study aimed at evaluating vulnerability in a water supply system and finding ways to improve its resiliency. The water supply system in the city of Sharjah, United Arab Emirates, is investigated as a case study for this research. The study developed an approach for improving resiliency of various components within a water supply system, including water source, treatment systems, and distribution networks. A network analysis of water distribution network was conducted in order to evaluate the vulnerable nodes based on their centrality and degree of interconnections. In addition, hydraulic analysis of the network was also conducted in order to identify the critical nodes that can be impacted by water shortages. Common and vulnerable nodes from both network and hydraulic analyses are identified to prioritize managerial actions for improvement of resiliency. A management plan is outlined in the paper to improve resiliency of the water supply system. The plan includes three different goals to achieve resiliency in a typical water supply system in the wake of a disaster event. These are reducing network vulnerability, increasing diversity of source water, and eliminating possibilities of water contamination. A set of priorities for implementation as maintenance activities is developed for use by management. The high-impact scenarios received higher priority, and low-impact scenarios received lower priority. In addition, the study recommends diversifying the source water, with less dependency on seawater. Diversifying the type of desalination techniques is recommended to increase the ability of water treatment plants for ensuring maintenance of desired water quality during times of disaster. The lessons learned from this case study will be useful to the management of infrastructures where resiliency needs to be improved. Major steps as outlined in this paper are identification of vulnerabilities, prioritizing action steps depending on the degree of impacts, and diversifying sources of supply and methods of treatments.