Distinct stores and the routing of water in the deep critical zone of a snow-dominated volcanic catchment
Author
White, AlissaMoravec, Bryan
McIntosh, Jennifer
Olshansky, Yaniv
Paras, Ben
Sanchez, R. Andres
Ferré, Ty P. A.
Meixner, Thomas
Chorover, Jon
Affiliation
Univ Arizona, Dept Soil Water & Environm SciUniv Arizona, Dept Hydrol & Atmospher Sci
Issue Date
2019-11-18
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COPERNICUS GESELLSCHAFT MBHCitation
White, A., Moravec, B., McIntosh, J., Olshansky, Y., Paras, B., Sanchez, R. A., Ferré, T. P. A., Meixner, T., and Chorover, J.: Distinct stores and the routing of water in the deep critical zone of a snow-dominated volcanic catchment, Hydrol. Earth Syst. Sci., 23, 4661–4683, https://doi.org/10.5194/hess-23-4661-2019, 2019.Rights
Copyright © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
This study combines major ion and isotope chemistry, age tracers, fracture density characterizations, and physical hydrology measurements to understand how the structure of the critical zone (CZ) influences its function, including water routing, storage, mean water residence times, and hydrologic response. In a high elevation rhyolitic tuff catchment in the Jemez River Basin Critical Zone Observatory (JRB-CZO) within the Valles Caldera National Preserve (VCNP) of northern New Mexico, a periodic precipitation pattern creates different hydrologic flow regimes during spring snowmelt, summer monsoon rain, and fall storms. Hydrometric, geochemical, and isotopic analyses of surface water and groundwater from distinct stores, most notably shallow groundwater that is likely a perched aquifer in consolidated collapse breccia and deeper groundwater in a fractured tuff aquifer system, enabled us to untangle the interactions of these groundwater stores and their contribution to streamflow across 1 complete water year (WY). Despite seasonal differences in groundwater response due to water partitioning, major ion chemistry indicates that deep groundwater from the highly fractured site is more representative of groundwater contributing to streamflow across the entire water year. Additionally, the comparison of streamflow and groundwater hydrographs indicates a hydraulic connection between the fractured welded tuff aquifer system and streamflow, while the shallow aquifer within the collapse breccia deposit does not show this same connection. Furthermore, analysis of age tracers and oxygen (δ18O) and stable hydrogen (δ2H) isotopes of water indicates that groundwater is a mix of modern and older waters recharged from snowmelt, and downhole neutron probe surveys suggest that water moves through the vadose zone both by vertical infiltration and subsurface lateral flow, depending on the lithology. We find that in complex geologic terrain like that of the JRB-CZO, differences in the CZ architecture of two hillslopes within a headwater catchment control water stores and routing through the subsurface and suggest that shallow groundwater does not contribute significantly to streams, while deep fractured aquifer systems contribute most to streamflow.Note
Open access journalISSN
1027-5606Version
Final published versionSponsors
National Science Foundation Division of Earth Sciences (NSF) [EAR-0724958, EAR-1331408]; Geological Society of Americaae974a485f413a2113503eed53cd6c53
10.5194/hess-23-4661-2019
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Except where otherwise noted, this item's license is described as Copyright © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License.