Geoelectrical Imaging of Hyporheic Exchange and Mixing of River Water and Groundwater in a Large Regulated River

Hyporheic mixing and surface water-groundwater interactions are critical processes in aquatic environments. Yet, there is a lack of methods for assessing the spatial extent and distribution of these mixing zones. This study applied time-lapse electrical resistivity (ER) imaging in a 60-m wide and 0....

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Bibliographic Details
Published in:Environmental science & technology 2011-02, Vol.45 (4), p.1407-1411
Main Authors: Cardenas, M. Bayani, Markowski, Michael S
Format: Article
Language:English
Subjects:
Aquatic ecosystems
Dams
Earth sciences
Earth, ocean, space
Environmental Processes
Environmental science
Exact sciences and technology
Fresh Water
Geophysics: general, magnetic, electric and thermic methods and properties
Groundwater
Hydrogeology
Hydrology
Hydrology. Hydrogeology
Internal geophysics
Rivers
Surface water
Water Movements
Water Pollutants, Chemical
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Summary:Hyporheic mixing and surface water-groundwater interactions are critical processes in aquatic environments. Yet, there is a lack of methods for assessing the spatial extent and distribution of these mixing zones. This study applied time-lapse electrical resistivity (ER) imaging in a 60-m wide and 0.7-m deep alluvial river whose stage periodically varied by 0.7 m due to dam operations to assess dynamic hyporheic mixing and surface water-groundwater interactions. Sixteen channel-spanning repeat ER tomograms (2D sections) over one flood cycle captured the dynamic ER distribution. We mapped a laterally discontinuous hyporheic zone, which had mainly river water circulating through it, several meters into the bed. Underneath the hyporheic zone was a transitional mixing zone intermittently flushed by mixing river water and deep groundwater. Minimally mixed groundwater dominated the deepest areas. ER imaging allows for unraveling hyporheic and deep mixing zone dynamics in large regulated rivers.
ISSN:0013-936X
1520-5851
DOI:10.1021/es103438a