Resilience Enhancement Methods for Water Distribution Networks

Abstract

Water is a basic necessity of all living beings for their survival on Earth. Hence, it has to be ensured to be distributed effectively. A water distribution system is a mesh of pipelines that distribute water to consumers. They are designed to satisfy adequately the water requirements for a combination of domestic, industrial and commercial purposes. A network designed with extreme care regarding pressure, losses, supply, quality of pipes and workmanship usually satisfies adequate water pressure at the consumer's taps for a specific rate of flow in an economical manner. But, due to the unexpected vertical growth and horizontal expansion, the designed network may not supply the assessed demand. This ultimately affects the supply level of low pressure zones, as well as remote places that are far away from the source. Hence, it is necessary to consider resiliency of the network at the design level of the water distribution system which can represent the capability of the network to meet additional demands or withstand demand fluctuations that may occur during peak hours. The basic principle used to improve the resilience is to increase the diameter of the pipe to the pipeline to achieve maximum flow velocity. Increasing the diameters of the various pipes of an optimally designed network or an existing network considerably increases the efficiency of the system due to the increase in its resilience index. Parallel piping system is another option adopted to enhance resilience, in which a stretch experiencing maximum velocity is chosen. An additional pipe is installed parallel to the existing pipe in that stretch, thereby increasing the flow of water from the source and decreasing the velocity in that stretch. This ultimately increases the resilience index of the system, thereby meeting the additional demand incurred on that system. This is illustrated using two benchmark networks available in literature. The results of the study indicate that the parallel pipe approach is found to be better than increasing the pipe size approach both in terms of resilience enhancement as well as economy.