Journal article
Flow and Residence Times of Dynamic River Bank Storage and Sinuosity‐Driven Hyporheic Exchange
Water resources research, Vol.53(10), pp.8572-8595
10/2017
DOI: 10.1002/2017WR021362
Abstract
Hydrologic exchange fluxes (HEFs) vary significantly along river corridors due to spatiotemporal changes in discharge and geomorphology. This variability results in the emergence of biogeochemical hot‐spots and hot‐moments that ultimately control solute and energy transport and ecosystem services from the local to the watershed scales. In this work, we use a reduced‐order model to gain mechanistic understanding of river bank storage and sinuosity‐driven hyporheic exchange induced by transient river discharge. This is the first time that a systematic analysis of both processes is presented and serves as an initial step to propose parsimonious, physics‐based models for better predictions of water quality at the large watershed scale. The effects of channel sinuosity, alluvial valley slope, hydraulic conductivity, and river stage forcing intensity and duration are encapsulated in dimensionless variables that can be easily estimated or constrained. We find that the importance of perturbations in the hyporheic zone's flux, residence times, and geometry is mainly explained by two‐dimensionless variables representing the ratio of the hydraulic time constant of the aquifer and the duration of the event (Γd) and the importance of the ambient groundwater flow (
Δh∗). Our model additionally shows that even systems with small sensitivity, resulting in small changes in the hyporheic zone extent, are characterized by highly variable exchange fluxes and residence times. These findings highlight the importance of including dynamic changes in hyporheic zones for typical HEF models such as the transient storage model.
Key Points
We present a reduced‐order model for dynamic bank storage and sinuosity‐driven hyporheic exchange
Dimensionless metrics can be used to describe the importance of transient forcing in river corridors
Even if hyporheic zone extent is constant, exchange fluxes and residence times vary significantly
Details
- Title: Subtitle
- Flow and Residence Times of Dynamic River Bank Storage and Sinuosity‐Driven Hyporheic Exchange
- Creators
- J. D. Gomez-Velez - New Mexico Institute of Mining and TechnologyJ. L. Wilson - New Mexico Institute of Mining and TechnologyM. B. Cardenas - The University of Texas at AustinJ. W. Harvey - United States Geological Survey
- Resource Type
- Journal article
- Publication Details
- Water resources research, Vol.53(10), pp.8572-8595
- DOI
- 10.1002/2017WR021362
- ISSN
- 0043-1397
- eISSN
- 1944-7973
- Number of pages
- 24
- Grant note
- New Mexico EPSCoR Track I (EAR‐0814449) USGS NAWQA and PES Programs Department of Earth & Environmental Science NSF (EAR‐1015100 ; EAR‐0955750 ; EAR‐1343861 ; EAR‐1344547)
- Language
- English
- Date published
- 10/2017
- Academic Unit
- Civil and Environmental Engineering
- Record Identifier
- 9984962530002771
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