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| Titel |
New advances for the recharge quantification in deep-seated landslide under tropical climate |
| VerfasserIn |
Pierre Belle, Bertrand Aunay, Bernard Ladouche, Patrick Lachassagne, Jean-Lambert Join |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250094229
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| Publikation (Nr.) |
 EGU/EGU2014-9629.pdf |
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| Zusammenfassung |
| The landslide activity is commonly controlled by the variation of hydraulic head inside the
instable mass. Consequently, the study of the aquifer recharge function is an essential step to
predict landslide dynamic. Under tropical climate, the intense rainfall precipitated
during the rainy season and the erosion rates generate large instabilities. However,
hydrogeological studies of landslides in tropical environments are mainly focused on surface
instabilities.
In this context, the Grand Ilet landslide (250 Mm3) (Reunion Island) allows us to
implement an innovative approach to quantify the landslide aquifer recharge in a tropical
humid climate. Here, we deploy during 2 years (2011 to 2012) surface water and groundwater
monitoring network (springs and piezometers) coupled with the monitoring of stable isotopes
of rainwater and groundwater. These data allow the establishment of a daily water
balance and the quantification of groundwater inflow and outflow at the landslide
scale.
The results of daily water balance show that the recharge during 2011-2012 period (1728
mm) constitutes 35% of the total rainfall (4777 mm). Furthermore the aquifer recharge occurs
mainly during the wet season (99% of annual recharge), for rainfall event greater
than 80 mm/event. The monitoring of stable isotopes supports and completes these
results: the isotopic signature of landslide groundwater appears comparable to the
isotopic signatures of wet season rainfalls. Moreover, the hydrologic monitoring
allow us to quantify exceptional low runoff coefficients ( |
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