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Dissertation
What Are the Hydroecological Drivers of Water Security in an Agricultural and Snowmelt-Dominated Region?
Washington State University
Doctor of Philosophy (PhD), Washington State University
2023
DOI:
https://doi.org/10.7273/000005288
Abstract
Water is a cornerstone of human productivity. A water-secure region has access to water in sufficient quantities, of adequate quality, and at the right time to meet the needs of humans and ecosystems. Over the 21st century, the combination of warming-induced shifts in hydrological regimes and greater water demands for food and energy due to rapid economic growth is likely to create water security challenges across the globe. The goal of this dissertation is to investigate how and to what extent the processes of land-use change, climate warming, and crop transpiration drive changes in water supply and demand in regions where the hydrology is strongly influenced by snow accumulation and melt. The research is focused on a commonly neglected element of water security in snow-dominated basins, that is, the seasonal alignment of meltwater flow and irrigation demand. The implications of shifts in water supply and demand timing for agricultural production, energy production, and instream flows for fish are evaluated and discussed. The geographical setting of this work is the Pacific Northwest Region, particularly the Columbia River Basin.
Analysis of the role played by water rights in moderating the impact of land-use/cover change on food, energy, and water subsystems showed that expanding irrigated area can enhance the productivity of food and energy crops, but it may do so at the cost of greater instream flow deficits and less hydropower production in summer. Analysis of shifts in irrigation demand timing for a variety of annual and perennial crops resulted in greater shifts in demand toward earlier timing among annuals compared to perennials. A partial-correlation analysis revealed that crop phenology, followed by sowing date, followed by growing season precipitation, are the primary contributing factors to shifts in water demand timing. Shifts in streamflow timing were found to be strongly associated with the fraction of runoff derived from snowmelt and the mean winter temperature. Watersheds most vulnerable to increasing separation between supply and demand timing are those with a large contribution from snowmelt, winter temperatures near 0°C, and a high proportion of cropland planted to annuals. Earlier water demand timing showed potential to mitigate increasing water right curtailment frequency due to earlier streamflow timing by a small amount. Finally, priority-based water right curtailment was shown to augment streamflow by an amount equal to or larger than curtailment in favor of instream flows.
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Details
- Title
- What Are the Hydroecological Drivers of Water Security in an Agricultural and Snowmelt-Dominated Region?
- Creators
- Matthew Allen Yourek
- Contributors
- Jennifer C Adam (Advisor)Jan Boll (Advisor)Kirti Rajagopalan (Committee Member)Sasha McLarty (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Civil and Environmental Engineering, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 337
- Identifiers
- 99901019634101842
- Language
- English
- Resource Type
- Dissertation