Module LS Factor
Calculation of slope length (LS) factor as used by the Universal Soil Loss Equation (USLE), based on slope and specific catchment area (SCA, as substitute for slope length).
References:
Boehner, J., Selige, T. (2006):
Spatial Prediction of Soil Attributes Using Terrain Analysis and Climate Regionalisation'
In: Boehner, J., McCloy, K.R., Strobl, J.: 'SAGA - Analysis and Modelling Applications', Goettinger Geographische Abhandlungen, Vol.115, p.13-27
Desmet & Govers (1996):
'A GIS Procedure for Automatically Calculating the USLE LS Factor on Topographically Complex Landscape Units'
Journal of Soil and Water Conservation, 51(5):427.433
Kinnell, P.I.A. (2005):
'Alternative Approaches for Determining the USLE-M Slope Length Factor for Grid Cells.'
http://soil.scijournals.org/cgi/content/full/69/3/674
Moore, I.D., Grayson, R.B., Ladson, A.R. (1991):
'Digital terrain modelling: a review of hydrogical, geomorphological, and biological applications'
Hydrological Processes, Vol.5, No.1
Wischmeier, W.H., Smith, D.D. (1978):
'Predicting rainfall erosion losses - A guide to conservation planning'
Agriculture Handbook No. 537: US Department of Agriculture, Washington DC.
- Author: O.Conrad (c) 2003
- Specification: grid
- Menu: Terrain Analysis|Hydrology|Topographic Indices
Parameters
| | Name | Type | Identifier | Description | Constraints |
|---|
| Input | Slope | Grid (input) | SLOPE | - | - |
| Catchment Area | Grid (input) | AREA | - | - |
| Output | LS Factor | Grid (output) | LS | - | - |
| Options | Area to Length Conversion | Choice | CONV | Derivation of slope lengths from catchment areas. These are rough approximations! Applies not to Desmet & Govers' method. | Available Choices:
[0] no conversion (areas already given as specific catchment area)
[1] 1 / cell size (specific catchment area)
[2] square root (catchment length)
Default: 0 |
| Method (LS) | Choice | METHOD | - | Available Choices:
[0] Moore et al. 1991
[1] Desmet & Govers 1996
[2] Boehner & Selige 2006
Default: 0 |
| Rill/Interrill Erosivity | Floating point | EROSIVITY | - | Minimum: 0.000000
Default: 1.000000 |
| Stability | Choice | STABILITY | - | Available Choices:
[0] stable
[1] instable (thawing)
Default: 0 |
Command-line
Usage: saga_cmd ta_hydrology 22 [-SLOPE <str>] [-AREA <str>] [-LS <str>] [-CONV <str>] [-METHOD <str>] [-EROSIVITY <str>] [-STABILITY <str>]
-SLOPE:<str> Slope
Grid (input)
-AREA:<str> Catchment Area
Grid (input)
-LS:<str> LS Factor
Grid (output)
-CONV:<str> Area to Length Conversion
Choice
Available Choices:
[0] no conversion (areas already given as specific catchment area)
[1] 1 / cell size (specific catchment area)
[2] square root (catchment length)
Default: 0
-METHOD:<str> Method (LS)
Choice
Available Choices:
[0] Moore et al. 1991
[1] Desmet & Govers 1996
[2] Boehner & Selige 2006
Default: 0
-EROSIVITY:<str> Rill/Interrill Erosivity
Floating point
Minimum: 0.000000
Default: 1.000000
-STABILITY:<str> Stability
Choice
Available Choices:
[0] stable
[1] instable (thawing)
Default: 0