Strategies for managing naturally occurring contaminants in groundwater basins of the Central Valley, California
- California's Central Valley provides some of the most productive agricultural land in the world. However, climate change is disrupting the hydrologic cycle and multiple stakeholders are extracting groundwater faster than it can be replenished. Such groundwater overdraft has degraded or depleted drinking water supplies, endangered groundwater dependent ecosystems, and severely damaged both crops and irrigation infrastructure. I employ qualitative, synthesis, and statistical modeling to address 1) the need for increasing California's water supply and 2) mitigating groundwater quality threats during managed aquifer recharge. In Chapter 2, I address the deleterious pathway we are on by qualitatively examining Central Valley farmer perceptions of the California water system through 30 semi-structured interviews. I describe the California farm as a coupled-infrastructure system with groundwater as a common pool resource, placing managed aquifer recharge as an economically viable option for sustainable groundwater management. I provide exploratory descriptive analysis of the economic, social-behavioral, and biophysical context of farmer decision-making with respect to groundwater quality and quantity. I explore farmers' beliefs about their roles in creating and mitigating overdraft, and I reveal farmers self-identifying as sustainable stewards of the land not solely motivated by profit. However, I also identify threats from naturally occurring contaminants such as arsenic and uranium. In Chapter 3, I propose recommendations for balancing the quantity of planned recharge with mitigation strategies that control the biogeochemical and hydrogeological mechanisms associated with naturally occurring threats. Further, on the basis of current decision support tools for siting managed aquifer recharge on farms, I propose balancing the quantity of planned recharge with mitigation strategies that control the biogeochemical and hydrogeological mechanisms associated with naturally occurring threats. Based on the need to balance quality and quantity during managed aquifer recharge, I identify the need to summarize available managed aquifer recharge siting tools and find room to augment them with naturally occurring threats. In Chapter 4, my work illustrates the benefit of augmenting managed aquifer recharge siting tools with predictive naturally occurring threat maps created with random forest modeling. I propose a scenario-based case study that emphasizes the need to balance reversing overdraft with maintaining or improving groundwater quality to ensure California has a sustainable water supply for all beneficial uses.
|Type of resource
|electronic resource; remote; computer; online resource
|1 online resource.
|Holmes, Randall Thomas
|Degree committee member
|Degree committee member
|Stanford Doerr School of Sustainability
|Emmett Interdisciplinary Program in Environment and Resources (Stanford University)
|Statement of responsibility
|Randall Thomas Holmes.
|Submitted to the Emmett Interdisciplinary Program in Environment and Resources.
|Thesis Ph.D. Stanford University 2023.
- © 2023 by Randall Thomas Holmes
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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