Impacts of neighborhood densification on water-energy-carbon nexus: Investigating water distribution and residential landscaping system

Abstract

Neighborhood densification is a strategy primarily applied to reduce per capita infrastructure and land requirement. In particular, densification alters residential landscaping that in turn affects water distribution systems. An integrated study of the water-energy-carbon (WEC) dynamics of water distribution and residential landscaping under neighborhood densification is lacking in the published literature. A conceptual framework was developed and applied as a case study to a planned neighborhood in the Okanagan Valley (BC, Canada). For this neighborhood, 11 alternative designs with varying combinations of single-family and multi-family lots representing different residential densities were investigated. Water consumption, energy use, and net carbon emissions by water distribution and residential landscaping systems were combined and represented by ecological footprint. The results show that per capita ecological footprint has a power relationship with net residential density despite of a linear relationship between population and net residential density. The power relationship reveals a high dependency of per capita ecological footprint on residential density, which helps to identify an optimal density. Two-dimensional analysis of the WEC nexus scenarios indicates that xeriscaping can reduce per capita ecological footprint ranging from roughly 1% reduction in high density to 66% in low density neighborhood. Also, the effects of xeriscaping on the WEC nexus are highly density dependent. This research can be extended by including varying neighborhood configuration and building stories. The results emphasize the importance of amending relevant policies for constructing medium to high-density buildings in urban neighborhoods to achieve an optimal WEC nexus.