Abstract
We estimated the effect of forest by simulating on surface failure caused by snowmelt at the slopes of forested and unforested areas in the Kobira River basin. The simulation model consisted of a snow model and a surface failure model . The snow model estimates snow depth distribution and snowmelt, using the heat balance method. The surface failure model estimates the ground water level and slope stability, using analyses of saturated-unsaturated infiltration and infinite slope stability model.
Generally, landslides are thought more likely on unforested slopes, because of increased snowmelt. In the Kobira River basin, however, forest prolonged snowmelt causing surface failures when heavy rainfall in early April coincided with the peak of snowmelt. The model verified that the presence of forest changed the landslide potential . This will make it possible to predict surface failures and debris flows during the snowmelt period . These results provide fundamental information for planning warning and evacuation systems to prevent sediment disasters.
