Sediment transport mechanisms on soil-mantled hillslopes

Landscape evolution is modeled widely using a simple creep law for complex processes of sediment transport. Here, field data show how a new transport model, combined with an exponential soil production law, better captures spatial variations of soil thick- ness on hillslopes. We combine parameterizations of simple and depth-dependent creep with overland flow to predict soil thickness and suggest how soil distribution evolves in response to climatic and tectonic forcing. We present an empirical expression for the response time of the system to external forcing that shows strong dependence on relief and is independent of soil production rate. We suggest that this parameterization may be used to quantify upland carbon storage and removal and predict impacts of defor- estation or rapid climatic changes.

[1]  William E. Dietrich,et al.  Quantification of soil production and downslope creep rates from cosmogenic 10Be accumulations on a hillslope profile , 1993 .

[2]  M. Kirkby,et al.  Hillslope Form and Process , 1972 .

[3]  I. Moore,et al.  Sediment Transport Capacity of Sheet and Rill Flow: Application of Unit Stream Power Theory , 1986 .

[4]  William E. Dietrich,et al.  Soil production on a retreating escarpment in southeastern Australia , 2000 .

[5]  William E. Dietrich,et al.  Evidence for nonlinear, diffusive sediment transport on hillslopes and implications for landscape morphology , 1999 .

[6]  A. Howard.  A detachment-limited model of drainage basin evolution , 1994 .

[7]  D. Montgomery,et al.  Hydrologic Processes in a Low-Gradient Source Area , 1995 .

[8]  H. Kooi,et al.  Escarpment evolution on high‐elevation rifted margins: Insights derived from a surface processes model that combines diffusion, advection, and reaction , 1994 .

[9]  P. Allen,et al.  Sediment flux from a mountain belt derived by landslide mapping , 1997 .

[10]  Robert S. Anderson,et al.  Evolution of the Santa Cruz Mountains, California, through tectonic growth and geomorphic decay , 1994 .

[11]  R. Anderson,et al.  Estimates of the rate of regolith production using and from an alpine hillslope , 1999 .

[12]  Alan D. Howard,et al.  BADLAND MORPHOLOGY AND EVOLUTION: INTERPRETATION USING A SIMULATION MODEL , 1997 .

[13]  Robert F. Stallard,et al.  Terrestrial sedimentation and the carbon cycle: Coupling weathering and erosion to carbon burial , 1998 .

[14]  M. Selby,et al.  Hillslope materials and processes , 1982 .

[15]  I. Rodríguez‐Iturbe,et al.  A coupled channel network growth and hillslope evolution model: 1. Theory , 1991 .

[16]  Ian P. Prosser,et al.  Sediment transport capacity relations for overland flow , 2000 .

[17]  M. Sambridge,et al.  Modelling landscape evolution on geological time scales: a new method based on irregular spatial discretization , 1997 .

[18]  William E. Dietrich,et al.  Cosmogenic nuclides, topography, and the spatial variation of soil depth , 1999 .

[19]  G. K. Gilbert.  The Convexity of Hilltops , 1909, The Journal of Geology.

[20]  David R. Montgomery,et al.  A process-based model for colluvial soil depth and shallow landsliding using digital elevation data , 1995 .

[21]  W. Dietrich,et al.  The soil production function and landscape equilibrium , 1997, Nature.

[22]  Clement G. Chase,et al.  Fluvial landsculpting and the fractal dimension of topography , 1992 .

[23]  W. Davis.  THE CONVEX PROFILE OF BAD-LAND DIVIDES. , 1892, Science.

[24]  M. Williams,et al.  Soil creep: problems raised by a 23 year study in Australia , 1999 .