Understanding patterns of groundwater flow are important when quantifying and mitigating threats to critical groundwater resources. Environmental tracers, determined from discrete sampling, could aid in characterizing spring systems through determining flow paths, recharge areas, and carbon cycling. This study explores the novel inclusion of δ13C of dissolved organic carbon (DOC), δ13C of dissolved inorganic carbon (DIC) and fluorescent dissolved organic matter (fDOM), along with more commonly used multi-tracer approaches that involve water isotopes, major ions, and saturation indices, to characterize springs of the Shivwits Plateau in Grand Canyon National Park, USA. Carbon isotope ratios and fDOM concentrations for all springs reflect source values associated with regional surface vegetation and heterotrophic degradation of terrestrial DOM. Principal component analyses show that springs can be grouped by geochemical variability into: (1) a shallow epikarst system, (2) a flow path through gypsiferous beds of the Toroweap Formation on the eastern side of the plateau, (3) a short canyon-slope flow path dominated by runoff, and (4) a deeper complex flow system in the Redwall Limestone characteristic of mixing of all other flow systems. As appropriations from the Colorado River already exceed its annual streamflow, characterizing groundwater resources for water supply in an increasingly arid climate will be paramount. These results demonstrate the effectiveness of geochemical techniques for groundwater flow characterization, particularly in inaccessible environments.
|Translated title of the contribution||Isotopic and geochemical tracers of groundwater flow in the Shivwits Plateau, Grand Canyon National Park, USA|
|Number of pages||16|
|State||Published - Mar 2022|
Bibliographical noteFunding Information:
The authors thank Jordon Munizzi and the staff of the Kentucky Stable Isotope Geochemistry Laboratory and Kentucky Geological Survey for assistance in geochemical analyses and method development. Field work assistance from Stefan Christie, Nicholas Steele, Natalie Jones, Adam Nolte, Vanessa Fichtner, Sarah Arpin, Hannah Chambless, Matt and Saj Zappitello, Andres Hernandez, Gina Lukoczki, and others was immensely helpful in completing this study. Finally, thank you to Alan Fryar at the University of Kentucky for help with preliminary editing and feedback as well as providing ideas for analyses and methods. We thank two reviewers and the editor for providing constructive feedback, which greatly improved the manuscript.
This study was supported by funding from the National Park Service in 2019 and 2020, the Geological Society of America’s John W. Hess Research Grant in 2019, and travel funds from the Department of Earth and Environmental Sciences in 2019. This research was conducted under NPS Research Permit GRCA-2019-SCI-0032.
© 2022, Springer-Verlag GmbH Germany, part of Springer Nature.
- Environmental tracers
- Stable isotopes
ASJC Scopus subject areas
- Water Science and Technology
- Earth and Planetary Sciences (miscellaneous)