Thesis Colloquium Dorothée van Oeveren

Hydrological hillslope processes in relation to shallow landslide sensitivity, considering heterogeneity in soil depth.

Organised by Hydrology and Quantitative Water Management

Thu 7 May 2015 10:00 to 10:30

Venue Gaia, gebouwnummer 101
Room Gaia 1
Hydrological hillslope processes in relation to shallow landslide sensitivity

Investigating shallow landslide sensitivity in relation to hydrological hillslope processes  is done extensively, but heterogeneity in soil depth is often neglected. It is important, since landslides often cause fatalities, that more accurate and precise predictions are made that will result in improved mitigation policies. Hence, the aim of this study is to qualitatively answer on which locations along a hillslope landslide sensitivity is higher and how certain variables act  upon landslide (in)stability. 4 unique high resolution bedrock- and surface input-data are abstracted from the Palona dataset, combined with high-resolution precipitation forcing for three major rainfall events of the Illgraben Catchment. Hillslope hydrology is described by Darcy, as formulated by Boussinesq. Landslide sensitivity is described by the Factor of Safety (FoS), assuming non-infinite/finite? slope stability and neglecting cohesion. Stationair and transient results provide insight in soil characteristics, local site specifics and the temporal behavior of landslide sensitivity, as expressed by FoS. The sub-surface backwater effect results in more sensitive footslopes than crests and deep/concave parts are more sensitive to landslides. From the local bedrock angle, the angle of repose and the porosity, the porosity is most influencing the landslide sensitivity. It is shown that heterogeneity in soil depth is of great importance for the potential to landslide formation.