Emergence and erosion: a model for rill initiation and development

Soil erosion by overland flow, resulting from infiltration-excess rainfall, generates rill networks on hillslope areas. The way in which these network s emerge and develop suggests that hillslope erosion functions as a self-or ganizing dynamic system. Based upon this argument, a model for soil erosion (RillGrow 1) has been developed: this operates at the spatial scale of rai ndrops and microtopography. In this paper the second generation of the mode l (RillGrow 2) is described and applied to four different soil surfaces. Re sults suggest that, even at this early stage in its development, RillGrow 2 is capable of replicating the successes of the earlier model and in some c ases of extending them. The success of both models suggests that this self- organizing view of rill generation may capture some fundamental aspects of the operation of real erosional systems. Copyright (C) 2000 John Wiley & So ns, Ltd.