Hydrological processes control the behaviour of many unstable slopes, andtheir importance for landslide activity is generally accepted. The presenceof fissures influences the storage capacity of a soil and affects theinfiltration processes of rainfall. The effectiveness of the fissure networkdepends upon fissure size, their spatial distribution, and connectivity.Moreover, fissure connectivity is a dynamic characteristic, depending on thedegree of saturation of the medium.This research aims to investigate the influence of the fissure network onhydrological responses of a landslide. Special attention is given to spatialand temporal variations in fissure connectivity, which makes fissures actboth as preferential flow paths for deep infiltration (disconnectedfissures) and as lateral groundwater drains (connected fissures). To thisend, the hydrological processes that control the exchange of water betweenthe fissure network and the matrix have been included in a spatiallydistributed hydrological and slope stability model. The ensuing feedbacks inlandslide hydrology were explored by running the model with one year ofmeteorological forcing. The effect of dynamic fissure connectivity wasevaluated by comparing simulations with static fissure patterns tosimulations in which these patterns change as a function of soilsaturation. The results highlight that fissure connectivity and fissurepermeability control the water distribution within landslides. Making thefissure connectivity function of soil moisture results in compositebehaviour spanning the above end members and introduces stronger seasonality of thehydrological responses.
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