Investigation of the Relationship Between Urban Form and the Energy Use of Water Distribution Systems
water demand , urban form , urban development , water supply and distribution systems , energy use
The physical configuration of water distribution systems is closely tied to the layout of the urban areas they serve. Over the last century, urban areas in North America have changed significantly in design, moving from high-density grid-based neighbourhoods to low-density suburban developments. The objective of this thesis is to examine the impact of urban form on the energy use in water distribution systems. This relationship was investigated at the neighbourhood-level through an energy analysis of scenarios characterized by different street topologies and population densities. The results suggest that gridiron neighbourhoods have lower energy requirements than warped parallel or cul-de-sac/loop neighbourhoods because their networks are highly connected. Gridiron neighbourhoods also have lower irrigation requirements due to their native high population densities, resulting in lower pumping energy requirements. The link between long-term urban development and energy use was investigated at the city-level through an energy analysis of a real-world, complex water distribution system. The system's three pressure zones corresponded well with areas from different periods of development, with distinctly different urban form characteristics. An energy balance approach was used to quantify the operating energy inputs and outputs for each of the system's pressure zones. The results suggest that there is an increasingly large "energy penalty" associated with expanding the city's urban fringe due to the sharp increase in ground elevation moving away from the water source. An alternative development scenario was also investigated, where instead of expanding outward, an existing urban area was intensified through an increase in population density. The results suggest that intensification can contribute to significant energy savings because more of the system's overall demand is met nearer to the water source, at lower elevation. Although the results obtained from this analysis are specific to the case study system, the general trends identified in the study can be relevant to other systems with similar characteristics, and could be used to guide future urban development plans.