ABSTRACT
The observation and measurement of processes operating on hillslopes is not new. Many nineteenth-century geologists were well aware of the significance of processes in the development of the landscape, and a casual perusal of much of the early geological literature will reveal many careful observations made on processes. In the last three decades, there has been a blossoming interest in processes, possibly sparked off by the failure of cyclic models to explain the origin of specific hillslope systems and possibly due to discrepancies between the real world and existing models, which could only be investigated by collecting data. Slope failures in soft rocks such as clays, and in regolith materials, may be shallow or deep-seated, depending on whether significant cohesive strength is present in the material. As overland flow increases in depth through a storm, it tends to reduce the influence of direct raindrop impact by cushioning the ground.
