Study of infiltration in a Sahelian gully erosion area using time-lapse resistivity mapping

Descloîtres, Marc; Ribolzi, Olivier; Troquer, Yann Le

doi:10.1016/s0341-8162(03)00038-9

Cited by 30 publications

(20 citation statements)

References 19 publications

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“…This was consistent with previous findings on basement by Descloitres et al [99], who observed a low infiltration under the gullies. Finally, the research by Malam Abdou et al [87] could constitute a first attempt of regionalization of the soil WHC in the Sahel, updating that by Descroix et al [51], based on the matching of exorheic/basement areas, as opposed to endorheic/sedimentary ones.…”

Section: A Common Explanation: the Reduction Of Both Hydraulic Conducsupporting

confidence: 94%

Evolution of Surface Hydrology in the Sahelo-Sudanian Strip: An Updated Review

Descroix

Guichard

Grippa

et al. 2018

Water

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Abstract:In the West African Sahel, two paradoxical hydrological behaviors have occurred during the last five decades. The first paradox was observed during the 1968-1990s 'Great Drought' period, during which runoff significantly increased. The second paradox appeared during the subsequent period of rainfall recovery (i.e., since the 1990s), during which the runoff coefficient continued to increase despite the general re-greening of the Sahel. This paper reviews and synthesizes the literature on the drivers of these paradoxical behaviors, focusing on recent works in the West African Sahelo/Sudanian strip, and upscaling the hydrological processes through an analysis of recent data from two representative areas of this region. This paper helps better determine the respective roles played by Land Use/Land Cover Changes (LULCC), the evolution of rainfall intensity and the occurrence of extreme rainfall events in these hydrological paradoxes. Both the literature review and recent data converge in indicating that the first Sahelian hydrological paradox was mostly driven by LULCC, while the second paradox has been caused by both LULCC and climate evolution, mainly the recent increase in rainfall intensity.

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Section: A Common Explanation: the Reduction Of Both Hydraulic Conducsupporting

confidence: 94%

Evolution of Surface Hydrology in the Sahelo-Sudanian Strip: An Updated Review

Descroix

Guichard

Grippa

et al. 2018

Water

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“…These systematic changes cannot be explained or related to any natural process. Descloitres et al (2003Descloitres et al ( , 2008b showed with synthetic data that time lapse inversion may produce artifacts due to the smoothness constraints especially with changes caused by shallow infiltration (decrease of resistivity), as mostly expected in our case.…”

Section: Ert Data Inversionsupporting

confidence: 80%

Monitoring hillslope moisture dynamics with surface ERT for enhancing spatial significance of hydrometric point measurements

Hübner¹,

Heller²,

Günther

et al. 2015

Hydrol. Earth Syst. Sci.

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Abstract. Besides floodplains, hillslopes are basic units that mainly control water movement and flow pathways within catchments of subdued mountain ranges. The structure of their shallow subsurface affects water balance, e.g. infiltration, retention, and runoff. Nevertheless, there is still a gap in the knowledge of the hydrological dynamics on hillslopes, notably due to the lack of generalization and transferability. This study presents a robust multi-method framework of electrical resistivity tomography (ERT) in addition to hydrometric point measurements, transferring hydrometric data into higher spatial scales to obtain additional patterns of distribution and dynamics of soil moisture on a hillslope. A geoelectrical monitoring in a small catchment in the eastern Ore Mountains was carried out at weekly intervals from May to December 2008 to image seasonal moisture dynamics on the hillslope scale. To link water content and electrical resistivity, the parameters of Archie's law were determined using different core samples. To optimize inversion parameters and methods, the derived spatial and temporal water content distribution was compared to tensiometer data. The results from ERT measurements show a strong correlation with the hydrometric data. The response is congruent to the soil tension data. Water content calculated from the ERT profile shows similar variations as that of water content from soil moisture sensors. Consequently, soil moisture dynamics on the hillslope scale may be determined not only by expensive invasive punctual hydrometric measurements, but also by minimally invasive time-lapse ERT, provided that pedo-/petrophysical relationships are known. Since ERT integrates larger spatial scales, a combination with hydrometric point measurements improves the understanding of the ongoing hydrological processes and better suits identification of heterogeneities.

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“…Resistivity variations with time are useful to locate the infiltration using apparent resistivity mapping, as shown in an arid gully area (Descloitres et al, 2003) or at the scale of a cultivated plot (Michot et al, 2003). Practically, apparent resistivity is measured at the surface using two current electrodes, A and B and two potential electrodes, M and N (see Reynolds, 1997).…”

Section: Ertmentioning

confidence: 99%

Characterization of seasonal local recharge using electrical resistivity tomography and magnetic resonance sounding

Descloîtres

Ruiz

Sekhar

et al. 2007

Hydrological Processes

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101

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International audienceA groundwater recharge process of heterogeneous hard rock aquifer in the Moole Hole experimental watershed, south India, is being studied to understand the groundwater flow behaviour. Significant seasonal variations in groundwater level are observed in boreholes located at the outlet area indicating that the recharge process is probably taking place below intermittent streams. In order to localize groundwater recharge zones and to optimize implementation of boreholes, a geophysical survey was carried out during and after the 2004 monsoon across the outlet zone. Magnetic resonance soundings (MRS) have been performed to characterize the aquifer and measure groundwater level depletion. The results of MRS are consistent with the observation in boreholes, but it suffers from degraded lateral resolution. A better resolution of the regolith/bedrock interface is achieved using electrical resistivity tomography (ERT). ERT results are confirmed by resistivity logging in the boreholes. ERT surveys have been carried out twice - before and during the monsoon - across the stream area. The major feature of recharge is revealed below the stream with a decrease by 80% of the calculated resistivity. The time-lapse ERT also shows unexpected variations at a depth of 20 m below the slopes that could have been interpreted as a consequence of a deep seasonal water flow. However, in this area time-lapse ERT does not match with borehole data. Numerical modelling shows that in the presence of a shallow water infiltration, an inversion artefact may take place thus limiting the reliability of time-lapse ERT. A combination of ERT with MRS provides valuable information on structure and aquifer properties respectively, giving a clue for a conceptual model of the recharge process: infiltration takes place in the conductive fractured-fissured part of the bedrock underlying the stream and clayey material present on both sides slows down its lateral dissipation

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Study of infiltration in a Sahelian gully erosion area using time-lapse resistivity mapping

Cited by 30 publications

References 19 publications

Evolution of Surface Hydrology in the Sahelo-Sudanian Strip: An Updated Review

Evolution of Surface Hydrology in the Sahelo-Sudanian Strip: An Updated Review

Monitoring hillslope moisture dynamics with surface ERT for enhancing spatial significance of hydrometric point measurements

Characterization of seasonal local recharge using electrical resistivity tomography and magnetic resonance sounding

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