A Socio-Hydrologic Assessment of Mountain Water Supply Vulnerability to Changing Snowmelt
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Authors
Gordon, Beatrice Louise
Issue Date
2022
Type
Dissertation
Language
Keywords
Alternative Title
Abstract
Climate change is accelerating disconnects between snowmelt-driven water supply and downstream demand. Identifying what makes people and places vulnerable to these disconnects can improve understanding of present conditions and help anticipate future changes in water management. This dissertation seeks to understand the potential for increasing disconnects between downstream agriculturally productive regions and their primary water supply—higher elevation, mountainous (upland) environments. We do so by focusing on agriculturally productive regions in the western United States (US) that are heavily reliant on seasonal snowmelt-driven streamflow, and using interdisciplinary tools such as big data, conceptual modeling, social science, and computational hydrology to assess vulnerability from the source (mountains) to demand (agriculture) We find that a process-based framework isolating three dominant mechanisms linking snow to streamflow helps explain changes in snowmelt-driven streamflow in 537 upland catchments throughout the US. We then use a hydrogeological framework and optimized averaging in a subset of our initial 537 catchments, highlighting the critical and often overlooked role of groundwater contributions in high, arid, and deep mountain catchments. Equipped with a more robust understanding of surface water and groundwater supplies in the western US, we then quantify the benefits of adaptation to changing snow resources particularly in hay-dominated agriculturally productive systems with smaller declines in snow relative to reservoir storage. Finally, we derive a flexible approach for expanding vulnerability assessments beyond the mountains and show that robust consideration of multiple aspects of vulnerability requires better measures of the social value of water as well as demand.