Integrating urban form and demographics in water-demand management: an empirical case study of Portland, Oregon

Theories of water-resource management suggest that water demand is mediated by three interacting factors: technological innovations, pricing structures, and individual behaviors and demographics. While these factors provide useful insights for ongoing water conservation strategies, such as outreach and education campaigns, pricing schemes, and incentives aimed at residential developments, few studies examine the relationship between land-use planning and water demand. This paper reports the results of a study on land-use zoning and development-induced water consumption in Portland, Oregon. We used a geographic information system to integrate land-use records, water-consumption data, sociodemographics, and property tax information for over 122 550 parcels of varying land uses, and employed multiregression analyses to measure the effect of urban form-as measured by both the type and the structure of land uses-on regional water demand. While our results corroborate previous studies that link demographic characteristics to water demand, we go further by identifying zoning and structural attributes of the households as explaining over 93% of water use in all parcels. The paper concludes with a discussion of the opportunities and challenges for coordinating water-resource management with land-use planning.