Individually, the partners in this proposal, in collaboration with key infrastructure owners and engineering companies, have been responsible for the instrumentation of 15 cut slopes and embankments, the development of numerical models which couple hydrological and geotechnical effects, and the development of laboratory and filed testing to provide parameters to populate these models.

These studies have helped to define the type of problem that is being faced and begin to understand some of the interactions between weather, soil and vegetation. However, further research is required in order to:

• better understand material behaviour - particularly the composite behaviour of soil, water, air and vegetation
• slope system behaviour - particularly the effects of temporal and spatial variations of material properties
• the relationships with environmental effects and engineering performance.

It is important for the sustainable management of infrastructure slopes (assessment, planning, repair, maintenance and adaptation) to have models that can assess the likely engineering performance of infrastructure slopes, both now and in the future.

Recent model development has started to consider the input of weather patterns, and can therefore model the potential effects of future climate. However it has become clear that these models are sensitive to the way in which a number of the physical processes and properties are incorporated, many of which are complex and difficult to quantify directly. A better understanding of the interactions between earthworks, vegetation and climate is required to formulate robust guidance on which maintenance approaches should be adopted and how they should be applied.