Transient landscapes: gully development and evolution using a landscape evolution model

Gullies are a common feature of many landforms and play a significant role in landscape evolution. They are transient landscape features that move along a drainage line incising into soil, alluvium or colluvium disturbing the catchment both headwards and along its banks. It is important to understand gully initiation, development and evolution as while they are transient features they are drivers of landscape change and erode and transport considerable volumes of sediment through the channel network. There has been considerable research into understanding gully development with many numerical predictive models developed. Here a computer-based landscape evolution model (SIBERIA) is examined for its ability to predict gully development in a catchment undisturbed by European agricultural practices. The simulations demonstrate that the SIBERIA model is able to produce gullies in the same position that are qualitatively and quantitatively morphologically similar to field data. The modelling suggests that the whole catchment is at risk of gullying and is in accordance with the field data which demonstrated that the presence of gullies was extensive throughout the catchment. The model also produces erosion rates within that of independently measured field data.