Christa Brelsford (Arizona State University; SFI Graduate Fellow)
Abstract. The phrase “Whiskey is for drinking; water is for fighting over,” often misattributed to Mark Twain, succinctly describes how water is thought about in the western United States. As urban populations grow, water managers are becoming increasingly concerned about water scarcity because their traditional tools for managing growing demand for water are becoming less useful. They have historically managed increasing water demand by developing new sources of water supply, but sources of unclaimed water are now rare. This has lead to conflict over existing sources and increasing attention to demand side management strategies. We perform the first quantitative assessment of the role that infrastructure change driven by population growth and new technology plays in reducing household level water consumption, especially in conjunction with several water conservation programs. By the end of our study period, homes constructed during the study period make up half of all structures in the city. We find that the largest drivers of Las Vegas’ decline in average household water consumption are changes in the average age of homes and changes in population location, both driven by substantial population growth. In established neighborhoods, the largest explainable driver of changes in household consumption is the observed decline in vegetation area. An additional analysis demonstrates that policies to reduce turf have significant potential to influence household consumption in established neighborhoods, with the water district spending about $4,900 to incentivize landscaping conversions that save enough water to support one additional household living in a newly constructed home. This research demonstrates the viability of landscape conversion programs to generate substantial water savings, and also emphasizes the importance of supporting water efficient new construction, so that water efficiency can be built into the infrastructure of a city as it grows, rather than requiring expensive retro-fitting programs.