Vulnerability and Resilience of Urban Water Systems under Uncertain Climate Change Scenarios

In this study, we improved the City of Las Vegas climate change detection and attribution using existing surface station data, new surface station temperature observations, and urban canopy model (UCM) simulations based on the Weather Research and Forecasting (WRF) Model. We address uncertainty and impacts of urban climate change on irrigation water demands for the city of Las Vegas. Current observed warming trend in the Las Vegas metro area were isolated using two components: (i) those associated with global/regional temperature trends, and (ii) those attributable to land cover and land use changes. We take into account the urban and population growth scenarios for our model to estimate the future changes from our initial parameters. For studying the biases in the attribution of local warming trends, we deployed an enhanced observational network consisting of 20 HOBO sensors that measure near surface (~ 2 m) air temperature and relative humidity. This urban network was designed to emphasize important biases on existing stations and specify the contributions of residential areas, golf courses, and other cooler patches within the urban heat island (UHI). Our working framework and enhanced observation network provides an unbiased measure of the UHI by compositing the phase and amplitude of the diurnal cycle of temperature. Preliminary results suggest that irrigation water demands will rise by 10-20 percent of current levels depending on precipitation and temperature projections.