Impacts of Water Quality on the Spatiotemporal Susceptibility of Water Distribution Systems

Maintaining water quality in distribution systems is crucial for ensuring safety of water supply. The distribution infrastructure is typically buried underground and it is often difficult to assess the condition of the system. In case of breakage of underground pipe network, external agents, like microorganisms may ingress into the distribution system which then react with residual disinfectant (chlorine) and result in faster decay. Understanding the chlorine decay is critical to ensuring the acceptable condition of the water distribution infrastructure. The objective of this study is to assess the spatiotemporal susceptibility of a water distribution network based on water quality variations. GIS based residual chlorine decay, temperature, and Langelier saturation index (LSI) profiles for the entire water distribution network are created using inverse distance weighting technique. Hotspot analysis is conducted to identify the vulnerable sections of the city's water distribution network based on residual chlorine. Spatial variations can not identify a consistent pattern of decay throughout the distribution system. However, some sections of the old part (North western) of the city show low residual chlorine levels compared to other locations. LSI values are negative in some source waters, leading to potential degradation of the distribution pipes. Temporal variations indicate that residual chlorine levels drop late summer and early fall. However, hotspot analysis identifies that some of the old part of Sharjah has consistently low residual chlorine levels, indicating considerable degradation of the distribution pipes.