The relationship of soil loss by interrill erosion to slope gradient.

Abstract The influence of slope gradient on erosion rate differs for rill and interrill conditions. Rill erosion increases substantially more with increasing slope gradient than interrill erosion. Combining the two erosion processes into single data sets led to the development of regression equations (e.g., USLE) that overestimated the effect of slope gradient on erosion rate for low slope gradients and short slopes. This study investigated the change in interrill erosion rate with slope gradient and examined its relationship to runoff velocity. A sandy loam (grey brown luvisol) was packed in 100×40×10 cm3 soil trays and subjected to simulated rainfall for a period of 75 min. Rain-impacted flow erosion and downslope splash were monitored, and runoff velocity measurements were made at three positions within the flume. Downslope splash erosion never accounted for more than 20% of the total erosion. Rain-impacted flow erosion peaked early in the simulation then decreased to a constant rate; erosion rate was therefore probably detachment-limited. For a constant runoff rate, rain-impacted flow erosion increased roughly with the square root of slope gradient, as did the runoff velocity. Soil loss was correlated (0.81) with runoff velocity under the experimental conditions.

[1]  L. D. Meyer,et al.  Influences of Muleh Rate and Slope Steepness on Interrill Erosion1 , 1974 .

[2]  Y. Le Bissonnais,et al.  Process-based analysis of aggregate stability effects on sealing, infiltration, and interrill erosion , 1998 .

[3]  M. G. Anderson,et al.  Overland flow and erosion. , 1990 .

[4]  P. Kinnell,et al.  Soil/slope gradient interactions in erosion by rain-impacted flow , 1993 .

[5]  P. I. A. Kinnell,et al.  Transport of a Noncohesive Sandy Mixture in Rainfall and Runoff Experiments 1 , 1978 .

[6]  J. Laflen,et al.  Soil dispersibility, rain properties, and slope interaction in rill formation and erosion , 1992 .

[7]  Soil erosion : experiments and models , 1990 .

[8]  A. Moss.  Effects of flow velocity variation on rain driven transportation and the role of rain impact in the movement of solids , 1988 .

[9]  A. Roy,et al.  The effect of slope gradient and length on the parameters of a sediment transport equation for sheetwash , 1989 .

[10]  J. M. Bradford,et al.  Comparison of interrill soil loss for laboratory and field procedures , 1993 .

[11]  D. Torri,et al.  Slope, aspect and surface storage. , 1996 .

[12]  Modelling erosion by rain-impacted flow. , 1990 .

[13]  A. J. Moss,et al.  Raindrop-stimulated transportation in shallow water flows: An experimental study , 1979 .

[14]  Gerard Govers,et al.  Transporting capacity of overland flow on plane and on irregular beds , 1986 .

[15]  R. Bryan,et al.  The influence of slope angle on final infiltration rate for interrill conditions , 1997 .

[16]  J. Poesen,et al.  The effect of soil surface slope on raindrop detachment , 1992 .

[17]  L. D. Meyer,et al.  How Row-Sideslope Length and Steepness Affect Sideslope Erosion , 1989 .

[18]  D. A. Barry,et al.  A Mathematical Model of Soil Erosion and Deposition Processes: I. Theory for a Plane Land Element , 1983 .

[19]  A. Roy,et al.  A study on the effect of spatial scale on the parameters of a sediment transport equation for sheetwash , 1996 .

[20]  M. Agassi,et al.  Soil Erosion, Conservation, and Rehabilitation , 1995 .

[21]  S. H. Luk,et al.  Use of the salt tracing technique to determine the velocity of overland flow , 1992 .

[22]  Jean Poesen,et al.  The hydrological response of soil surfaces to rainfall as affected by cover and position of rock fragments in the top layer , 1990 .

[23]  J. K. Mitchell,et al.  Slope steepness effects on soil loss from disturbed lands , 1987 .

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

[25]  Gerard Govers,et al.  Relationship between discharge, velocity and flow area for rills eroding loose, non‐layered materials , 1992 .

[26]  Ramesh P. Rudra,et al.  The Roles of Rainfall and Runoff in the Sediment Transport Capacity of Interrill Flow , 1987 .

[27]  J. Blackard,et al.  Slope Angle-Interrill Soil Loss Relationships for Slopes up to 50% 1 , 1982 .

[28]  L. Band.  Field parameterization of an empirical sheetwash transport equation , 1985 .

[29]  G. R. Foster,et al.  RUSLE: Revised universal soil loss equation , 1991 .

[30]  Malcolm G. Anderson,et al.  Process studies in hillslope hydrology. , 1993 .

[31]  J. M. Laflen,et al.  Soil Strength, Slope, and Rainfall Intensity Effects on Interrill Erosion , 1986 .

[32]  C. K. Mutchler,et al.  Revised slope steepness factor for the universal soil loss equation , 1987 .

[33]  Joe M. Bradford,et al.  Analyses of Slope and Runoff Factors Based on the WEPP Erosion Model , 1993 .

[34]  J. Bradford,et al.  Laboratory determination of interrill soil erodibility , 1995 .