Karst spring processes and groundwater storage implications in high-elevation, semi-arid southwestern United States

Donovan, Keegan Matthew (2021) Karst spring processes and groundwater storage implications in high-elevation, semi-arid southwestern United States. Masters thesis, Northern Arizona University.

	Text Donovan_2021_karst_spring_processes_groundwater_storage_implications_h.pdf - Published Version Restricted to Repository staff only Download (3MB) | Request a copy
	Spreadsheet Donovan_2021_Appendix A- Water Quality.xlsx - Supplemental Material Download (42kB)
	Text Donovan_2021_Appendix B1- Clover Discharge.csv - Supplemental Material Download (78kB)
	Text Donovan_2021_Appendix B2- Hoxworth Discharge.csv - Supplemental Material Download (36kB)
	Text Donovan_2021_Appendix B3- North Canyon Discharge.csv - Supplemental Material Download (10kB)
	Text Donovan_2021_Appendix B4- Robberx27s Roost Discharge.csv - Supplemental Material Download (12kB)
	Spreadsheet Donovan_2021_Appendix C- Rating Curves.xlsx - Supplemental Material Download (66kB)
	Spreadsheet Donovan_2021_Appendix D- Stable Isotope Data.xlsx - Supplemental Material Download (24kB)
	Spreadsheet Donovan_2021_Appendix E- Climate Data.xlsx - Supplemental Material Download (820kB)

Abstract

Karst springs and aquifers are significant resources globally yet continue to be poorly understood because of their heterogeneity in porosity and response to climate variability. In semi-arid, mountainous regions where total precipitation and groundwater recharge rates will likely decline due to climate change, improved understandings of karst groundwater recharge processes are imperative to plan for future hydrologic responses. The Colorado Plateau is a high-elevation, heavily dissected region of over 2,000 m thickness of sedimentary rock units containing multiple layered karst aquifers. This is the first study to use hydrograph analyses on four springs in the uppermost regional Coconino aquifer (C aquifer) of the Colorado Plateau in Arizona to detail karst aquifer response to recharge. Coupled hydrograph and stable isotope (δ18O and δ2H) analyses document seasonal recharge and storage processes in the C aquifer. A critical relationship between seasonal snowpack timing and duration of seasonal ephemeral spring discharge indicates seasonal buffering and attenuation to drought. Hydrograph analyses show rapid hydrologic responses to precipitation in two ephemeral karst spring systems and quick drainage without extended seasonal snowmelt contribution. As climate change intensifies in drought-ridden areas of the world, aquifer and spring ecosystem conditions will significantly worsen without mitigation measures. The recharge and groundwater flow processes demonstrated in this study of a complex karst system support informed water resource decision-making on the Colorado Plateau and other climate-sensitive regions around the world.

Item Type:	Thesis (Masters)
Publisher’s Statement:	© Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author.
Keywords:	Climate; Groundwater; Karst springs; Recession; Recharge; Snowmelt; Colorado Plateau; Arizona
Subjects:	Q Science > QE Geology
NAU Depositing Author Academic Status:	Student
Department/Unit:	Graduate College > Theses and Dissertations College of the Environment, Forestry, and Natural Sciences > School of Earth Sciences and Environmental Sustainability
Date Deposited:	25 Feb 2022 16:45
Last Modified:	25 Feb 2022 16:45
URI:	https://openknowledge.nau.edu/id/eprint/5750

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