Implications of Urban Form on Water Distribution Systems Performance

This paper presents the results of an investigation into the relationship between urban form and the performance of a water distribution system. The effect of new development or redevelopment on the performance of an expanded rehabilitation of the well-known Anytown water distribution system is examined to provide an insight into their interaction, which can be considered along with other aspects of renewal to achieve more sustainable urban areas. A range of urban growth rates, urban form and water efficiency strategies are studied in relation to the system’s key performance indicators of total cost, resilience and water quality. The urban forms considered in this work are compact/uniform, monocentric, polycentric and edge developments. These development patterns are representative of common development approaches widely applied in urban planning. They also correspond to future settlement patterns, based on adopting four future (socio-economic) scenarios so called Policy Reform (PR), Fortress World (FW), New Sustainability Paradigm (NSP), and Market Forces (MF) respectively. Three growth rates and two water demand efficiency levels are considered. It is concluded the rate and type of urban development has major implications for the redesign and operation of existing water infrastructure in terms of total cost, water quality and system resilience, with uniform expansion (PR) resulting in the most cost-effective system upgrade by a considerable margin. Polycentric expansion as a representative urban form for New Sustainability Paradigm is the least cost-effective if it relies on centralised water distribution system to provide service to customers. Edge expansion (MF) has both the cheapest and the most expensive expansion costs depending on location of the expansion. Monocentric urban development (FW) does not result in the most cost-effective system contrary to what has been reported in the literature. Water efficiency measures had relatively little impact on overall performance as it was balanced out with demand increase due to new growth.