Effective rainfall: a significant parameter to improve understanding of deep-seated rainfall triggering landslide – a simple computation temperature based method applied to Séchilienne unstable slope (French Alps)

Vallet, Aurélien; Bertrand, Catherine; Mudry, Jacques

doi:10.5194/hessd-10-8945-2013

Cited by 8 publications

(13 citation statements)

References 31 publications

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“…The variation of intensity with intermittency affects the partitioning of rainfall into infiltration and overland flow. Indeed, it is really the effective rainfall, rather than the open-field rainfall, that is important in terms of increasing soil moisture content (Vallet et al, 2013). Plant communities, surface litter, and biological soil crusts can affect the conversion of incident rainfall to effective rainfall through their influence on interception loss and related processes.…”

Section: Discussionmentioning

confidence: 99%

Intra‐event intermittency of rainfall: an analysis of the metrics of rain and no‐rain periods

Dunkerley

2015

Hydrological Processes

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Abstract:The metric or 'observable' properties of intra-event rainfall intermittency (IERI) are quantified using a 10-year record from arid Fowlers Gap, Australia. Rainfall events were delineated using the minimum inter-event time (MIT) criterion, using eight values in the range of 1 h -24 h. Within events, no-rain periods were defined as corresponding to rainfall rates R < 0.1 mm/h or R < 0.2 mm/h (both less than typical wet-canopy evaporation rates during rainfall). In this way, rainfall events were subdivided into rain and no-rain periods. Intermittency was characterised using two measures: the fraction of rainless time within an event, and the duration of the longest rainless period. Events identified using a minimum inter-event time (MIT) of 24 h included on average 9.4 h of contiguous no-rain time (47.5% of the mean event duration), and only 6.8 h of contiguous rain. Total IERI averaged 51.1% for these events. Events defined with MIT = 6 h (a value commonly adopted in the literature) exhibited a mean of 1.53 h of no-rain and 9.04 h of contiguous rain. Total IERI averaged 13.9% for these events for R < 0.1 mm/h, but reached 39.2% if no-rain periods were taken as those of <0.2 mm/h. The maximum contiguous no-rain period for events defined using MIT = 6 h was 10.9 h from an event of 12.6 h duration, and this represents 86.5% of the event duration. Results demonstrate that smaller, shorter, and less intense rainfall events tend to exhibit higher IERI than larger, longer, and more intense events. IERI is relevant to the understanding of land surface processes. Information on the metric properties of IERI in different rainfall types (convective and stratiform) and rainfall climates (arid, maritime, and wet tropical) may prove to have significance for diverse studies in land surface hydrology.

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Section: Discussionmentioning

confidence: 99%

Intra‐event intermittency of rainfall: an analysis of the metrics of rain and no‐rain periods

Dunkerley

2015

Hydrological Processes

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“…The piezometric level oscillations are estimated to be about 100 m after long‐term water recharge. Waters flow rapidly, in a few hours to a few days, at small rates of maximum 0.2 L/min, and no permanent flow or pore pressure was recorded [ Vallet et al ., ].…”

Section: Field Evidence For the Effects Of Deep Fluids On The Mechanimentioning

confidence: 99%

Deep fluids can facilitate rupture of slow‐moving giant landslides as a result of stress transfer and frictional weakening

Cappa

Guglielmi

Viseur

et al. 2014

Geophysical Research Letters

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[1] Landslides accommodate slow, aseismic slip and fast, seismic rupture, which are sensitive to fluid pressures and rock frictional properties. The study of strain partitioning in the Séchilienne landslide (France) provides a unique insight into this sensitivity. Here we show with hydromechanical modeling that a significant part of the observed landslide motions and associated seismicity may be caused by poroelastic strain below the landslide, induced by groundwater table variations. In the unstable volume near the surface, calculated strain and rupture may be controlled by stress transfer and friction weakening above the phreatic zone and reproduce well high-motion zone characteristics measured by geodesy and geophysics. The key model parameters are friction weakening and the position of groundwater level, which is sufficiently constrained by field data to support the physical validity of the model. These results are of importance for the understanding of surface strain evolution under weak forcing. Citation: Cappa, F., Y. Guglielmi, S. Viseur, and S. Garambois (2014), Deep fluids can facilitate rupture of slowmoving giant landslides as a result of stress transfer and frictional weakening, Geophys. Res. Lett., 41,[61][62][63][64][65][66]

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“…As a reminder, Ar corresponds to the efficient rainfall (Reff) from which the runoff (S) is subtracted. Using efficient rainfall (Reff) instead of rainfall (R) improves the correlation between the rainfall process and the displacement velocity, in particular for large landslides [41] where runoff (S) is small. The parameter Ar depends upon soil water balance, which in turn depends upon (i) soil-water reservoir changes The larger the landslide, the more complex such factors will be and the more difficult it will be to carry out hydrogeological investigations because of the huge amounts of material being mobilized [31].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…In a tropical humid climate and in particular in the intertropical zone, the large amount of rainfall and high intensity of rainfall episodes are favorable environmental conditions for triggering landslides [23,[41][42][43][44]. Despite this, most hydrogeological landslide studies in the tropics focus on small surface (thickness < 20 m) instabilities [42,[45][46][47][48], which pose a more direct and frequent threat to the population.…”

Section: Introductionmentioning

confidence: 99%

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Control of Tropical Landcover and Soil Properties on Landslides’ Aquifer Recharge, Piezometry and Dynamics

Belle

Aunay²,

Lachassagne³

et al. 2018

Water

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Among the processes controlling landslide dynamics, piezometry plays a major role. The characterization of a landslide’s aquifer recharge (=inflows) is thus indispensable for predicting displacements. In this research, the recharge of the large Grand Ilet landslide in the humid tropical, Reunion Island was characterized through a multi-disciplinary and robust hydrological approach, notably comprising a precise water budget of the landslide (outflows = inflows). Surface processes play a major role in the landslide recharge regime. Runoff is less than 1% of rainfall (2400 mm/year) due to the soil’s high permeability. A large quantity of water (250 mm) is adsorbed in this shallow layer. This reservoir is submitted to high real evapotranspiration (1500 mm/year) due to the dense tropical broad-leaved vegetation. This explains the low aquifer recharge (860 mm/year), the fact that only major rainfall episodes during the rainy season induce recharge, with a consequent increase in landslide velocity, and finally low outflow from the landslide. Therefore, among other operational recommendations, it is necessary to maintain natural vegetation cover over such landslide surface in order to limit aquifer recharge and thus displacements. This study provides a methodological framework for landslide studies, particularly for modeling their recharge/piezometry, and key parameters of their dynamics.

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Effective rainfall: a significant parameter to improve understanding of deep-seated rainfall triggering landslide – a simple computation temperature based method applied to Séchilienne unstable slope (French Alps)

Cited by 8 publications

References 31 publications

Intra‐event intermittency of rainfall: an analysis of the metrics of rain and no‐rain periods

Intra‐event intermittency of rainfall: an analysis of the metrics of rain and no‐rain periods

Deep fluids can facilitate rupture of slow‐moving giant landslides as a result of stress transfer and frictional weakening

Control of Tropical Landcover and Soil Properties on Landslides’ Aquifer Recharge, Piezometry and Dynamics

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