Form and function in hillslope hydrology: in situ imaging and characterization of flow-relevant structures
The study deals with the identification and characterization of rapid subsurface flow structures through pedo- and geo-physical measurements and irrigation experiments at the point, plot and hillslope scale. Our investigation of flow-relevant structures and hydrological responses refers to the g...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-07-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://www.hydrol-earth-syst-sci.net/21/3749/2017/hess-21-3749-2017.pdf |
| Summary: | The study deals with the identification and characterization of
rapid subsurface flow structures through pedo- and geo-physical measurements
and irrigation experiments at the point, plot and hillslope scale. Our
investigation of flow-relevant structures and hydrological responses refers
to the general interplay of form and function, respectively. To obtain a
holistic picture of the subsurface, a large set of different laboratory,
exploratory and experimental methods was used at the different scales. For
exploration these methods included drilled soil core profiles, in situ
measurements of infiltration capacity and saturated hydraulic conductivity,
and laboratory analyses of soil water retention and saturated hydraulic
conductivity. The irrigation experiments at the plot scale were monitored
through a combination of dye tracer, salt tracer, soil moisture dynamics, and
3-D time-lapse ground penetrating radar (GPR) methods. At the hillslope scale
the subsurface was explored by a 3-D GPR survey. A natural storm event and an
irrigation experiment were monitored by a dense network of soil moisture
observations and a cascade of 2-D time-lapse GPR <q>trenches</q>. We show that
the shift between activated and non-activated state of the flow paths is
needed to distinguish structures from overall heterogeneity. Pedo-physical
analyses of point-scale samples are the basis for sub-scale structure
inference. At the plot and hillslope scale 3-D and 2-D time-lapse GPR
applications are successfully employed as non-invasive means to image
subsurface response patterns and to identify flow-relevant paths. Tracer
recovery and soil water responses from irrigation experiments deliver a
consistent estimate of response velocities. The combined observation of form
and function under active conditions provides the means to localize and
characterize the structures (this study) and the hydrological processes
(companion study Angermann et al., 2017, this issue). |
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| ISSN: | 1027-5606 1607-7938 |