Modelling vegetation growth and its impact on slope hydrology and stability

The importance of vegetation for slope processes is widely acknowledged. For instance vegetation can decrease the amount of rainfall reaching the ground as it stores water in the canopy. Vegetation also removes water from the ground by the evaporation-transpiration process and tends to strengthen the soil via its root network. Therefore vegetation is an important factor to take into account when evaluating landslide risk. However, although vegetation is dynamic and evolves through time, slope hydrology and stability models do not allow vegetation to vary over time. The proposed research will relax this critical limitation by allowing all vegetation components to vary dynamically, therefore effectively letting vegetation grow as a function of the age of the plant, the species, the current climatic conditions and water availability in the soil directly within the model. The proposed research is an important stepping stone to answer two fundamental questions for slope hydrology and stability analysis. Firstly it is critical to understand at what stage of growth vegetation starts reinforcing a slope. This is particularly relevant in the context of 'soft' approaches to landslide risk reduction which use vegetation as a cost effective and often community based way to manage landslide risk. Secondly climatic conditions are changing globally and will impact vegetation development and water availability on slopes. Modelled climate data for the next decades is readily available for a range of CO2 scenarios but we lack a means to evaluate landslide risk over the next decades in regions where vegetation is due to vary due to climatic forcing. The proposed research is cross disciplinary and will attract interest from a range of stakeholders both in the UK and overseas and across the natural sciences an engineering spectrum.