Variability of permeability and seepage characteristics in soil landslides: a test case in the Three Gorges Reservoir Area, China

This study presents assessments of the spatial variability of a soil landslide in the Three Gorges Reservoir Area in China. The results challenge the idea that variability of permeability within a landslide is secondary. Consequently, it cannot be assessed through single representative values. It was found that its variability spans two orders of magnitude, a consequence of it being influenced by both morphology and regolith properties. Identification of zones that display comparable behavior can be done through assessment of remote-sensing images collected by drones, as growth patterns of vegetation correspond well with zones that displayed similar permeability coefficients within the landslide body. Furthermore, extensive variability of permeability was caused by a diverse range of seepage mechanisms, namely pipe network flow, interface network seepage and pore water seepage. Thus, the hydraulic behavior of large landslide bodies is remarkably complex.