Harnessing emerging data sources to uncover new dimensions of human-water dynamics during drought

Addressing modern challenges facing the urban water sector requires a suite of strategies, including infrastructure modernization, supply diversification, the integration of distributed infrastructure, and enhanced demand-side management, aimed at increasing the resilience, flexibility, and sustainability of our water systems. Making these changes necessary for urban water reinvention requires a deep knowledge of water use patterns, drivers, and trends. Without a holistic understanding of water use behavior by heterogeneous customers and during different policy and climate conditions, water agencies and urban planners cannot make optimal infrastructure investments, design appropriate supply portfolios, or implement effective conservation and efficiency campaigns. Yet water use is multifaceted, continually evolving, and linked to many different demographic, built environment, social, hydrologic, and political dimensions. These complexities, combined with historic data constraints, have led to many uncertainties about modern urban water use regimes. The arrival of the digital era offers unique opportunities for uncovering new dimensions of water use and gaining a more detailed understanding of evolving water use trends. Emerging data sources, increased data availability, new data collection technologies, and online platforms open the door for analyses that were not previously possible. Thus, the goal of the first four studies in this dissertation is to improve understanding of urban water use behavior through the integration and modeling of novel datasets, in turn providing a roadmap for future data-driven studies. The first study develops a unique method for quantifying drought-related news media coverage and then links this coverage to public interest through the proxy of internet search frequency data. Then, this news media coverage, measured by article volume, is integrated into regional water use models as a covariate, in turn assessing the relationship between drought saliency and water use. The results of this study demonstrate the important role that drought awareness plays in water use behavior for customers across heterogeneous service areas and highlights the importance of public communication. The second study investigates drought-related water conservation by customers in a previously unstudied urban water sector: nonresidential large landscape irrigation. By harnessing water use data from dedicated outdoor smart meters, water use is modeled at a weekly time-scale. A particularly novel aspect of this study is the comparison of irrigators using potable versus recycled water, subject to different policy regimes, but who conserved in parallel patterns due to ubiquitous drought awareness. This study also provides evidence for the influence of location on nonresidential urban irrigation and landscapes, especially the role of neighborhood affluence on water conservation backslide. The third study examines urban irrigation, vegetation greenness, and climate interactions during drought. Through the coupling of high-temporal resolution water use data from dedicated outdoor smart meters and high-spatial resolution multispectral aerial imagery data, results demonstrate that sustained irrigation during extremely hot drought cannot maintain vegetation vigor. These findings suggest the need to rethink urban landscaping choices and planning, including the role of climate-appropriate landscapes and tradeoffs between urban green spaces and water use. The fourth study leverages data from an online real estate aggregator, Zillow, to overcome previous constraints faced by researchers quantifying features of the built environment. Neighborhood clusters developed through a sequence of unsupervised machine learning algorithms provide evidence for the importance of including urban form when evaluating both indoor and outdoor water use, contrary to many studies which classify customers solely based on income levels. Additionally, these neighborhoods provide spatial scales and regions for which distributed infrastructure planning and conservation and efficiency outreach may be appropriate. Finally, water use models reveal complex, nonlinear drivers of water use and conservation. The implications of these first four studies indicate a need to re-think water management in the 21st century and suggest ways to increase urban water resilience through demand-side management, water reuse, water-efficient urban planning, and climate-appropriate landscaping. However, these changes also require new approaches to financing and governance, and the water sector must embrace new strategies that promote innovation. For example, collaborative and multi-sector ventures, enhanced customer engagement, and incentive-based funding models offer alternatives to the traditional top-down, siloed governance structures that are no longer appropriate for the modern infrastructure model. The final two studies in this dissertation address these challenges. By looking to existing strategies used in the electricity sector, the potential for novel mechanisms to be adapted to the water sector is examined. First, a financing and governance framework is developed for integrating distributed water solutions into our current centralized network. Then, best practices for the use of public benefit funds, one financing strategy, is analyzed for application in the water sector. Together these studies pave the way for the new era of urban water management. Overall, this research advances the field of urban water research by integrating a suite of unconventional datasets, coupling multiple modeling techniques, and examining water use at various spatial (regional, utility, neighborhood, and customer) and temporal (biennial, annual, summer, monthly, weekly) scales. The novel insights provided by this work can help decision makers in the water sector better understand customer behavior, which in turn can lead to more optimal decision making related to infrastructure investment, demand-side management efforts, and urban planning standards for both indoor and outdoor features of the built environment. This research opens the door for future data-driven water resources management.

Advisor: Luthy Richard G. 
Cain Bruce D.
Ajami Newsha