Soils and slopes in a humid temperate environment: A simulation study

A three dimensional simulation of the landsurface system is presented, which includes the processes of weathering, soil creep and fluvial erosion. Soils represent a deposit in equilibrium between the processes of weathering and erosion. The simulated drainage basin with a fixed exit point reproduces the “closed” system dynamics of the Davisian model, in which however slopes still attain a dynamic equilibrium form. Within the basin the overall mean soil depth very rapidly reaches a constant value even though a considerable redistribution of material is still to occur. This implies a rapid establishment of a balance between the process of weathering and erosion. By contrast the detailed pattern of soil depths on individual slopes is established much more slowly, only after the slopes themselves come to equilibrium. The equilibrium configuration of soils under soil creep shows a slight downslope increase in depths, and major increases in soil depth are restricted to locations where external constraints force an accumulation of material.