Detachment, entrainment, and transport processes in field-sized areas are the primary sources of contaminants and therefore must be modeled accurately. Most physically-based models currently use crude methods, usually assuming sheet flow, to describe hydraulic processes. Sheet flow rarely occurs in nature. Flow paths converge with other flow paths to form small channels. Information on velocity and bed shear in these small channels is essential in determining detachment, entrainment, and transport.
Values are significantly different for small channel flow than for sheet flow.
Thus, alternative approaches are needed to represent overland flow. A unique field instrumentation system was designed and used to obtain drainage networks of field-sized areas. Analysis of the data thus far has shown that the fractal dimension of erosion plot data is very similar to that obtained using major river networks. The work has also resulted in a conceptual framework for predicting rill networks by coupling observed link characteristics with topologic theory from river morphology. 1997 Regents of the University of Minnesota.