SAGA-GIS Tool Library Documentation (v6.1.0)

Tool MMF-SAGA Soil Erosion Model

Soil erosion modelling with a modified MMF (Morgan-Morgan-Finney) model (Morgan & Duzant 2008).
This tool is called MMF-SAGA because some things have been implemented differently compared to the original publication. The most important are:



A more detailed description of the model, its modifications, and model application is provided by Setiawan (2012), chapter 6.
Currently, a number of additional grid datasets are outputted to facilitate model evaluation. This can be easily changed within the source code.


References:
Morgan, R.P.C. (2001): A simple approach to soil loss prediction: a revised Morgan-Morgan-Finney model. Catena 44: 305-322.

Morgan, R.P.C., Duzant, J.H. (2008): Modified MMF (Morgan-Morgan-Finney) model for evaluating effects of crops and vegetation cover on soil erosion. Earth Surf. Process. Landforms 32: 90-106.

Setiawan, M. A. (2012): Integrated Soil Erosion Management in the upper Serayu Watershed, Wonosobo District, Central Java Province, Indonesia. Dissertation at the Faculty of Geo- and Atmospheric Sciences of the University of Innsbruck, Austria.

Parameters

 NameTypeIdentifierDescriptionConstraints
InputDigital Terrain ModelGrid (input)DTMDTM, digital terrain model [m]-
SlopeGrid (input)SS, slope [rad]-
Channel Network (*)Grid (optional input)CHANNELChannel network, all other cells NoData-
Permament InterceptionGrid (input)PIPI, permanent interception expressed as the proportion [between 0-1] of rainfall-
Canopy CoverGrid (input)CCCC, canopy cover expressed as a portion [between 0-1] of the soil surface protected by vegetation or crop-
Plant HeightGrid (input)PHPH, plant height [m], representing the effective height from which raindrops fall from the crop or vegetation-
Ratio EvapotranspirationGrid (input)EtEoEt/Eo, ratio of actual to potential evapotranspiration-
Ground coverGrid (input)GCGC, Ground cover expressed as a portion [between 0-1] of the soil surface protected by vegetation or crop cover on the ground-
Diameter plant elementsGrid (input)DD, Average diameter [m] of the individual plants elements (stem, leaves) at the ground surface-
Number plant elementsGrid (input)NVNV, Number of plant elements per unit area [number/unit area] at the ground surface-
Soil moisture (at FC)Grid (input)MSMS, Soil moisture at field capacity [% w/w]-
Bulk density top layerGrid (input)BDBD, Bulk density of the top layer [Mg/m3]-
Effective hydrological depthGrid (input)EHDEHD, Effective hydrological depth of the soil [m]-
Sat. lateral permeabilityGrid (input)LPLP, Saturated lateral permeability of the soil [m/day]-
Percentage claysGrid (input)PER_Cc, Percentage clays [%]-
Percentage siltGrid (input)PER_Zz, Percentage silt [%]-
Percentage sandGrid (input)PER_Ss, Percentage sand [%]-
Percentage rock fragmentsGrid (input)STST, Percentage rock fragments on the soil surface [%]-
Surface roughness (*)Grid (optional input)RFRRFR, Surface roughness [cm/m]. In case the surface roughness is not provided as input, v_flow_t is set to 1.0, i.e. natural soil surface roughness is not accounted for.-
Meteorological data (*)Table (optional input)TAB_METEOMeteorological data for multiple timestep modelling [model step (day); temperature (Celsius); rainfall (mm), rainfall intensity (mm/h); rainfall duration (day); timespan (days)]-
OutputInterflow (*)Grid (optional output)IFIF-
Mean runoffGrid (output)QQ, estimation of mean runoff [mm]-
Mean soil lossGrid (output)SLSL, estimation of mean soil loss [kg]-
Effective RainfallGrid (output)RfRf-
Total Kinetic EnergyGrid (output)KEKE-
Soil moisture storage capacityGrid (output)RcRc-
Transport Capacity ClayGrid (output)TCcTCc-
Transport Capacity SiltGrid (output)TCzTCz-
Transport Capacity SandGrid (output)TCsSLs-
Available ClayGrid (output)GcGc-
Available SiltGrid (output)GzGz-
Available SandGrid (output)GsGs-
Sediment Balance ClayGrid (output)SLcSLc-
Sediment Balance SiltGrid (output)SLzSLz-
Sediment Balance SandGrid (output)SLsSLs-
Transport Condition ClayGrid (output)TCONDcSediment Limited [0], Transport Limited (SL = TC) [1], Transport Limited (SL = G) [2]-
Transport Condition SiltGrid (output)TCONDzSediment Limited [0], Transport Limited (SL = TC) [1], Transport Limited (SL = G) [2]-
Transport Condition SandGrid (output)TCONDsSediment Limited [0], Transport Limited (SL = TC) [1], Transport Limited (SL = G) [2]-
Upslope Flow WidthGrid (output)W_upW_up-
OptionsGrid systemGrid systemPARAMETERS_GRID_SYSTEM--
Output file pathFile pathOUT_PATHFull path to the directory for the output grids of each model step-
Simulate InterflowBooleanINTERFLOWSimulate interflowDefault: 1
Mean temperatureFloating pointTT, mean temperature [degree C]Default: 18.000000
Timespan (days)IntegerTIMESPANThe number of days to model.Minimum: 1
Maximum: 365
Default: 30
RainfallFloating pointRR, height of precipitation in timespan [mm]Default: 200.000000
Rainfall intensityFloating pointII, rainfall intensity [mm/h]Default: 20.000000
Rainfall DurationFloating pointRnRn, number of rain days in timespan [-]Default: 20.000000
Relationship KE - IChoiceKE_I_METHODRelationship between kinetic energy (KE) and rainfall intensity (I)Available Choices:
[0] North America east of Rocky Mountains (Wischmeier & Smith 1978)
[1] North-western Europe (Marshall & Palmer)
[2] Mediterranean-type climates (Zanchi & Torri 1980)
[3] Western Mediterranean (Coutinho & Tomas 1995)
[4] Tropical climates (Hudson 1965)
[5] Eastern Asia (Onaga et al. 1998)
[6] Southern hemisphere climates (Rosewell 1986)
[7] Bogor, West-Java, Indonesia (McISaac 1990)
Default: 0
Flow Depth (actual flow velocity)Floating pointFLOWD_VAThe flow depth used to calculate the actual flow velocity [m] (e.g. 0.005 unchannelled flow, 0.01 shallow rills, 0.25 deeper rills.Minimum: 0.000000
Default: 0.005000
Route Soil along Channel NetworkBooleanCHANNELTRANSPORTRoute soil loss along channel network to outletDefault: 0
(*) optional

Command-line

Usage: saga_cmd sim_erosion 0 [-DTM <str>] [-S <str>] [-CHANNEL <str>] [-PI <str>] [-CC <str>] [-PH <str>] [-EtEo <str>] [-GC <str>] [-D <str>] [-NV <str>] [-MS <str>] [-BD <str>] [-EHD <str>] [-LP <str>] [-PER_C <str>] [-PER_Z <str>] [-PER_S <str>] [-ST <str>] [-RFR <str>] [-TAB_METEO <str>] [-OUT_PATH <str>] [-INTERFLOW <str>] [-T <double>] [-TIMESPAN <num>] [-IF <str>] [-R <double>] [-I <double>] [-Rn <double>] [-KE_I_METHOD <str>] [-FLOWD_VA <double>] [-CHANNELTRANSPORT <str>] [-Q <str>] [-SL <str>] [-Rf <str>] [-KE <str>] [-Rc <str>] [-TCc <str>] [-TCz <str>] [-TCs <str>] [-Gc <str>] [-Gz <str>] [-Gs <str>] [-SLc <str>] [-SLz <str>] [-SLs <str>] [-TCONDc <str>] [-TCONDz <str>] [-TCONDs <str>] [-W_up <str>]
  -DTM:<str>             	Digital Terrain Model
	Grid (input)
  -S:<str>               	Slope
	Grid (input)
  -CHANNEL:<str>         	Channel Network
	Grid (optional input)
  -PI:<str>              	Permament Interception
	Grid (input)
  -CC:<str>              	Canopy Cover
	Grid (input)
  -PH:<str>              	Plant Height
	Grid (input)
  -EtEo:<str>            	Ratio Evapotranspiration
	Grid (input)
  -GC:<str>              	Ground cover
	Grid (input)
  -D:<str>               	Diameter plant elements
	Grid (input)
  -NV:<str>              	Number plant elements
	Grid (input)
  -MS:<str>              	Soil moisture (at FC)
	Grid (input)
  -BD:<str>              	Bulk density top layer
	Grid (input)
  -EHD:<str>             	Effective hydrological depth
	Grid (input)
  -LP:<str>              	Sat. lateral permeability
	Grid (input)
  -PER_C:<str>           	Percentage clays
	Grid (input)
  -PER_Z:<str>           	Percentage silt
	Grid (input)
  -PER_S:<str>           	Percentage sand
	Grid (input)
  -ST:<str>              	Percentage rock fragments
	Grid (input)
  -RFR:<str>             	Surface roughness
	Grid (optional input)
  -TAB_METEO:<str>       	Meteorological data
	Table (optional input)
  -OUT_PATH:<str>        	Output file path
	File path
  -INTERFLOW:<str>       	Simulate Interflow
	Boolean
	Default: 1
  -T:<double>            	Mean temperature
	Floating point
	Default: 18.000000
  -TIMESPAN:<num>        	Timespan (days)
	Integer
	Minimum: 1
	Maximum: 365
	Default: 30
  -IF:<str>              	Interflow
	Grid (optional output)
  -R:<double>            	Rainfall
	Floating point
	Default: 200.000000
  -I:<double>            	Rainfall intensity
	Floating point
	Default: 20.000000
  -Rn:<double>           	Rainfall Duration
	Floating point
	Default: 20.000000
  -KE_I_METHOD:<str>     	Relationship KE - I
	Choice
	Available Choices:
	[0] North America east of Rocky Mountains (Wischmeier & Smith 1978)
	[1] North-western Europe (Marshall & Palmer)
	[2] Mediterranean-type climates (Zanchi & Torri 1980)
	[3] Western Mediterranean (Coutinho & Tomas 1995)
	[4] Tropical climates (Hudson 1965)
	[5] Eastern Asia (Onaga et al. 1998)
	[6] Southern hemisphere climates (Rosewell 1986)
	[7] Bogor, West-Java, Indonesia (McISaac 1990)
	Default: 0
  -FLOWD_VA:<double>     	Flow Depth (actual flow velocity)
	Floating point
	Minimum: 0.000000
	Default: 0.005000
  -CHANNELTRANSPORT:<str>	Route Soil along Channel Network
	Boolean
	Default: 0
  -Q:<str>               	Mean runoff
	Grid (output)
  -SL:<str>              	Mean soil loss
	Grid (output)
  -Rf:<str>              	Effective Rainfall
	Grid (output)
  -KE:<str>              	Total Kinetic Energy
	Grid (output)
  -Rc:<str>              	Soil moisture storage capacity
	Grid (output)
  -TCc:<str>             	Transport Capacity Clay
	Grid (output)
  -TCz:<str>             	Transport Capacity Silt
	Grid (output)
  -TCs:<str>             	Transport Capacity Sand
	Grid (output)
  -Gc:<str>              	Available Clay
	Grid (output)
  -Gz:<str>              	Available Silt
	Grid (output)
  -Gs:<str>              	Available Sand
	Grid (output)
  -SLc:<str>             	Sediment Balance Clay
	Grid (output)
  -SLz:<str>             	Sediment Balance Silt
	Grid (output)
  -SLs:<str>             	Sediment Balance Sand
	Grid (output)
  -TCONDc:<str>          	Transport Condition Clay
	Grid (output)
  -TCONDz:<str>          	Transport Condition Silt
	Grid (output)
  -TCONDs:<str>          	Transport Condition Sand
	Grid (output)
  -W_up:<str>            	Upslope Flow Width
	Grid (output)