Effect of riparian vegetation on stream bank stability in small agricultural catchments

In order to fill this gap we established hydrological and mechanical monitoring of selected test plots within a stream bank, covered with different types of vegetation, typical for Norwegian agricultural areas (grass, shrubs and trees). The soil moisture, groundwater level and stream water level were continuously monitored. Additionally, soil porosity and shear strength were measured regularly. Observed hydrological trends and differences between three plots (grass, tree and shrub) were analysed and formed the input base for stream bank stability modeling. We did not find particular differences between the grass and shrub plot but we did observe a significantly lower soil moisture content, lower soil porosity and higher shear strength within the tree plot. All three plots were stable during the monitoring period, however modeling scenarios made it possible to analyse potential differences in stream bank stability under different vegetation cover depending on root reinforcement and slope angle.