Modelling the effect of forest cover on shallow landslides at the river basin scale
Date
2010
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Abstract
The potential for reducing the occurrence of shallow landslides through targeted reforestation of critical
parts of a river basin is explored through mathematical modelling. Through the systematic investigation
of land management options, modelling allows the optimum strategies to be selected ahead of any real
intervention in the basin. Physically based models, for which the parameters can be evaluated using
physical reasoning, offer particular advantages for predicting the effects of possible future changes in land
use and climate. Typically a physically based landslide model consists of a coupled hydrological model
(for soil moisture) and a geotechnical slope stability model, along with an impact model, such as basin
sediment yield. An application of the SHETRAN model to the 65.8-km2 Guabalcón basin in central Ecuador
demonstrates a technique for identifying the areas of a basin most susceptible to shallow landsliding and
for quantifying the effects of different vegetation covers on landslide incidence. Thus, for the modelled
scenario, increasing root cohesion from 300 to 1500 Pa causes a two-thirds reduction in the number of
landslides. Useful information can be obtained even on the basis of imperfect data availability but model
output should be interpreted carefully in the light of parameter uncertainty.
Resumen
Keywords
Ecuador, Landslides, Modelling, Model Uncertainty, Reforestation, River Basin, Root-Binding, Shetran