Chapter 8: Design of Water Distribution Systems

Water distribution systems (WDSs) vary from simple to complex. The main objective of all water systems is to supply safe water for the cheapest cost. These systems are designed based on least cost and enhanced reliability considerations, and design principles should satisfy both hydraulic and engineering requirements. The hydraulic requirements include pressure, velocity, sufficient flow, minimum operational cost and so on, and the engineering requirements involve selection of durable materials, system component configuration, ease of access to components and so on.

This chapter begins by considering the design objectives of WDSs. It describes performance indicators that can be used to drive WDS design. The chapter then introduces optimisation techniques and how they can be applied in planning and design of conventional and intermittent WDSs. This is followed by the discussion of decentralised WDSs, focusing on clustering model and procedures for optimising the boundaries of decentralised WDSs. The chapter includes a discussion on the need to develop WDSs that can cope with future uncertainties and change requirements. To complement this, the chapter concludes by providing a brief look at the impacts of the COVID-19 pandemic on the operation of the WDSs and highlights the need for future preparedness. An alternative approach to build resiliency in the wake of the COVID-19 is also discussed.