MMF-SAGA Soil Erosion Model

Author(s)	(c) 2009-2026 V. Wichmann, M. Setiawan
Library ID	sim_erosion
Tool ID	0
Version	1.1
Menu	Simulation \| Erosion

Description

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:

the extension of the model to support spatially distributed modelling
the introduction of a "Channel Network" layer
the introduction of a "rainfall duration" (time span) parameter
the exposure of the flow depth parameter

A more detailed description of the model, its modifications, and model application is provided by Setiawan (2012), chapter 6.

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. PDF

Parameters

	Name	Type	Identifier	Description	Constraints
Input	Digital Terrain Model	grid, input	`DTM`	The digital terrain model [m].	-
	Slope	grid, input	`S`	The terrain slope [radians].	-
	Channel Network	grid, input, optional	`CHANNEL`	The channel network, encoded by values other than NoData.	-
	Surface Roughness	grid, input, optional	`RFR`	The surface roughness (RFR) [cm/m]. If the surface roughness is not provided, natural soil surface roughness is not accounted for (i.e. v_flow_t is set to 1).	-
	Permanent Interception	grid, input, optional	`PI`	The permanent interception (PI) by vegetation, expressed as the proportion of rainfall [0-1].	-
	Canopy Cover	grid, input, optional	`CC`	The canopy cover (CC) expressed as a portion of the soil surface protected by vegetation or crop [0-1].	-
	Plant Height	grid, input, optional	`PH`	The plant height (PH), representing the effective height from which raindrops fall from the crop or vegetation [m].	-
	Ratio Evapotranspiration	grid, input, optional	`EtEo`	The ratio (Et/Eo) of actual to potential evapotranspiration [0-1].	-
	Ground Cover	grid, input, optional	`GC`	Ground cover (GC) expressed as a portion of the soil surface protected by vegetation or crop cover on the ground [0-1].	-
	Diameter Plant Elements	grid, input, optional	`D`	The average diameter (D) of the individual plants elements (stem, leaves) at the ground surface [m].	-
	Number Plant Elements	grid, input, optional	`NV`	The number of plant elements (NV) per unit area at the ground surface [number/m²].	-
	Soil Moisture (at FC)	grid, input, optional	`MS`	The soil moisture content at field capacity (MS) [% w/w].	-
	Bulk Density Top Layer	grid, input, optional	`BD`	The bulk density of the top soil layer [Mg/m³].	-
	Effective Hydrological Depth	grid, input, optional	`EHD`	The effective hydrological depth (EHD) of the soil [m].	-
	Sat. Lateral Permeability	grid, input, optional	`LP`	The saturated lateral permeability (LP) of the soil [m/day]	-
	Percentage Clay	grid, input, optional	`PER_C`	The percentage clay (c) [%].	-
	Percentage Silt	grid, input, optional	`PER_Z`	The percentage silt (z) [%].	-
	Percentage Sand	grid, input, optional	`PER_S`	The percentage sand (s) [%].	-
	Percentage Rock Fragments	grid, input, optional	`ST`	The percentage of rock fragments (ST) on the soil surface [%].	-
	Meteorological Data	table, input, optional	`TAB_METEO`	Meteorological data for multiple timestep modelling, columns: [model step (day)] [temperature (Celsius)] [rainfall (mm)] [rainfall intensity (mm/h)] [rainfall duration (day)] [timespan (days)].	-
Output	Runoff	grid, output	`Q`	Average simulated runoff (Q) [mm].	-
	Soil Loss	grid, output	`SL`	Average soil loss [kg/m²].	-
	Interflow	grid, output, optional	`IF`	IF, Interflow [mm]	-
	Effective Rainfall	grid, output, optional	`Rf`	Effective Rainfall (Rf) [mm].	-
	Total Kinetic Energy	grid, output, optional	`KE`	Total kinetic energy (KE) [J/m²].	-
	Soil Moisture Storage Capacity	grid, output, optional	`Rc`	Soil moisture storage capacity (Rc) [mm].	-
	Transport Capacity Clay	grid, output, optional	`TCc`	Transport capacity clay (TCc) [kg/m²].	-
	Transport Capacity Silt	grid, output, optional	`TCz`	Transport capacity silt (TCz) [kg/m²].	-
	Transport Capacity Sand	grid, output, optional	`TCs`	Transport capacity sand (TCs) [kg/m²].	-
	Available Clay	grid, output, optional	`Gc`	Available clay (Gc) [kg/m²].	-
	Available Silt	grid, output, optional	`Gz`	Available silt (Gz) [kg/m²].	-
	Available Sand	grid, output, optional	`Gs`	Available sand (Gs) [kg/m²].	-
	Sediment Balance Clay	grid, output, optional	`SLc`	Sediment balance clay (SLc) [kg/m²].	-
	Sediment Balance Silt	grid, output, optional	`SLz`	Sediment balance silt (SLz) [kg/m²].	-
	Sediment Balance Sand	grid, output, optional	`SLs`	Sediment balance sand (SLs) [kg/m²].	-
	Transport Condition Clay	grid, output, optional	`TCONDc`	sediment limited [0], transport limited (SL = TC) [1], transport limited (SL = G) [2]	-
	Transport Condition Silt	grid, output, optional	`TCONDz`	sediment limited [0], transport limited (SL = TC) [1], transport limited (SL = G) [2]	-
	Transport Condition Sand	grid, output, optional	`TCONDs`	sediment limited [0], transport limited (SL = TC) [1], transport limited (SL = G) [2]	-
	Upslope Flow Width	grid, output, optional	`W_up`	Upslope Flow Width [m].	-
Options	Default	floating point number	`PI_DEFAULT`	default value if no grid has been selected	Minimum: 0.000000 Maximum: 1.000000 Default: 0.12
	Default	floating point number	`CC_DEFAULT`	default value if no grid has been selected	Minimum: 0.000000 Maximum: 1.000000 Default: 0.8
	Default	floating point number	`PH_DEFAULT`	default value if no grid has been selected	Minimum: 0.000000 Default: 0.8
	Default	floating point number	`EtEo_DEFAULT`	default value if no grid has been selected	Minimum: 0.000000 Maximum: 1.000000 Default: 0.75
	Default	floating point number	`GC_DEFAULT`	default value if no grid has been selected	Minimum: 0.000000 Maximum: 1.000000 Default: 0.4
	Default	floating point number	`D_DEFAULT`	default value if no grid has been selected	Minimum: 0.000000 Default: 0.1
	Default	floating point number	`NV_DEFAULT`	default value if no grid has been selected	Minimum: 0.000000 Default: 5
	Default	floating point number	`MS_DEFAULT`	default value if no grid has been selected	Minimum: 0.000000 Default: 0.2
	Default	floating point number	`BD_DEFAULT`	default value if no grid has been selected	Minimum: 0.000000 Default: 1.3
	Default	floating point number	`EHD_DEFAULT`	default value if no grid has been selected	Minimum: 0.000000 Default: 0.12
	Default	floating point number	`LP_DEFAULT`	default value if no grid has been selected	Minimum: 0.000000 Default: 25
	Default	floating point number	`PER_C_DEFAULT`	default value if no grid has been selected	Minimum: 0.000000 Maximum: 100.000000 Default: 20
	Default	floating point number	`PER_Z_DEFAULT`	default value if no grid has been selected	Minimum: 0.000000 Maximum: 100.000000 Default: 30
	Default	floating point number	`PER_S_DEFAULT`	default value if no grid has been selected	Minimum: 0.000000 Maximum: 100.000000 Default: 45
	Default	floating point number	`ST_DEFAULT`	default value if no grid has been selected	Minimum: 0.000000 Maximum: 100.000000 Default: 30
	Output File Path	file path	`OUT_PATH`	The full path to the folder to which the output grids of each simulation step are written.	-
	Simulate Interflow	boolean	`INTERFLOW`	Simulate interflow.	Default: 1
	Mean Temperature	floating point number	`T`	The mean temperature (T) [C°]	Default: 18
	Timespan	integer number	`TIMESPAN`	The number of days to model [days].	Minimum: 1 Maximum: 365 Default: 30
	Rainfall	floating point number	`R`	The height of precipitation (R) in timespan [mm].	Minimum: 0.000000 Default: 200
	Rainfall Intensity	floating point number	`I`	The rainfall intensity (I) [mm/h].	Minimum: 0.000000 Default: 20
	Rainfall Duration	integer number	`Rn`	The number of rain days (Rn) in timespan [days].	Minimum: 0 Default: 20
	Relationship KE - I	choice	`KE_I_METHOD`	The relationship 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 point number	`FLOWD_VA`	The flow depth used to calculate the actual flow velocity [m]. For example: 0.005 for unchannelled flow, 0.01 for shallow rills, 0.25 for deeper rills.	Minimum: 0.000000 Default: 0.005
	Route Soil along Channel Network	boolean	`CHANNELTRANSPORT`	Route soil loss along channel network to outlet	Default: 0

Command Line


Usage: saga_cmd sim_erosion 0 [-DTM ] [-S ] [-CHANNEL ] [-RFR ] [-PI ] [-PI_DEFAULT ] [-CC ] [-CC_DEFAULT ] [-PH ] [-PH_DEFAULT ] [-EtEo ] [-EtEo_DEFAULT ] [-GC ] [-GC_DEFAULT ] [-D ] [-D_DEFAULT ] [-NV ] [-NV_DEFAULT ] [-MS ] [-MS_DEFAULT ] [-BD ] [-BD_DEFAULT ] [-EHD ] [-EHD_DEFAULT ] [-LP ] [-LP_DEFAULT ] [-PER_C ] [-PER_C_DEFAULT ] [-PER_Z ] [-PER_Z_DEFAULT ] [-PER_S ] [-PER_S_DEFAULT ] [-ST ] [-ST_DEFAULT ] [-Q ] [-SL ] [-IF ] [-Rf ] [-KE ] [-Rc ] [-TCc ] [-TCz ] [-TCs ] [-Gc ] [-Gz ] [-Gs ] [-SLc ] [-SLz ] [-SLs ] [-TCONDc ] [-TCONDz ] [-TCONDs ] [-W_up ] [-TAB_METEO ] [-OUT_PATH ] [-INTERFLOW ] [-T ] [-TIMESPAN ] [-R ] [-I ] [-Rn ] [-KE_I_METHOD ] [-FLOWD_VA ] [-CHANNELTRANSPORT ]
  -DTM:                Digital Terrain Model
	grid, input
  -S:                  Slope
	grid, input
  -CHANNEL:            Channel Network
	grid, input, optional
  -RFR:                Surface Roughness
	grid, input, optional
  -PI:                 Permanent Interception
	grid, input, optional
  -PI_DEFAULT:      Default
	floating point number
	Minimum: 0.000000
	Maximum: 1.000000
	Default: 0.12
  -CC:                 Canopy Cover
	grid, input, optional
  -CC_DEFAULT:      Default
	floating point number
	Minimum: 0.000000
	Maximum: 1.000000
	Default: 0.8
  -PH:                 Plant Height
	grid, input, optional
  -PH_DEFAULT:      Default
	floating point number
	Minimum: 0.000000
	Default: 0.8
  -EtEo:               Ratio Evapotranspiration
	grid, input, optional
  -EtEo_DEFAULT:    Default
	floating point number
	Minimum: 0.000000
	Maximum: 1.000000
	Default: 0.75
  -GC:                 Ground Cover
	grid, input, optional
  -GC_DEFAULT:      Default
	floating point number
	Minimum: 0.000000
	Maximum: 1.000000
	Default: 0.4
  -D:                  Diameter Plant Elements
	grid, input, optional
  -D_DEFAULT:       Default
	floating point number
	Minimum: 0.000000
	Default: 0.1
  -NV:                 Number Plant Elements
	grid, input, optional
  -NV_DEFAULT:      Default
	floating point number
	Minimum: 0.000000
	Default: 5
  -MS:                 Soil Moisture (at FC)
	grid, input, optional
  -MS_DEFAULT:      Default
	floating point number
	Minimum: 0.000000
	Default: 0.2
  -BD:                 Bulk Density Top Layer
	grid, input, optional
  -BD_DEFAULT:      Default
	floating point number
	Minimum: 0.000000
	Default: 1.3
  -EHD:                Effective Hydrological Depth
	grid, input, optional
  -EHD_DEFAULT:     Default
	floating point number
	Minimum: 0.000000
	Default: 0.12
  -LP:                 Sat. Lateral Permeability
	grid, input, optional
  -LP_DEFAULT:      Default
	floating point number
	Minimum: 0.000000
	Default: 25
  -PER_C:              Percentage Clay
	grid, input, optional
  -PER_C_DEFAULT:   Default
	floating point number
	Minimum: 0.000000
	Maximum: 100.000000
	Default: 20
  -PER_Z:              Percentage Silt
	grid, input, optional
  -PER_Z_DEFAULT:   Default
	floating point number
	Minimum: 0.000000
	Maximum: 100.000000
	Default: 30
  -PER_S:              Percentage Sand
	grid, input, optional
  -PER_S_DEFAULT:   Default
	floating point number
	Minimum: 0.000000
	Maximum: 100.000000
	Default: 45
  -ST:                 Percentage Rock Fragments
	grid, input, optional
  -ST_DEFAULT:      Default
	floating point number
	Minimum: 0.000000
	Maximum: 100.000000
	Default: 30
  -Q:                  Runoff
	grid, output
  -SL:                 Soil Loss
	grid, output
  -IF:                 Interflow
	grid, output, optional
  -Rf:                 Effective Rainfall
	grid, output, optional
  -KE:                 Total Kinetic Energy
	grid, output, optional
  -Rc:                 Soil Moisture Storage Capacity
	grid, output, optional
  -TCc:                Transport Capacity Clay
	grid, output, optional
  -TCz:                Transport Capacity Silt
	grid, output, optional
  -TCs:                Transport Capacity Sand
	grid, output, optional
  -Gc:                 Available Clay
	grid, output, optional
  -Gz:                 Available Silt
	grid, output, optional
  -Gs:                 Available Sand
	grid, output, optional
  -SLc:                Sediment Balance Clay
	grid, output, optional
  -SLz:                Sediment Balance Silt
	grid, output, optional
  -SLs:                Sediment Balance Sand
	grid, output, optional
  -TCONDc:             Transport Condition Clay
	grid, output, optional
  -TCONDz:             Transport Condition Silt
	grid, output, optional
  -TCONDs:             Transport Condition Sand
	grid, output, optional
  -W_up:               Upslope Flow Width
	grid, output, optional
  -TAB_METEO:          Meteorological Data
	table, input, optional
  -OUT_PATH:           Output File Path
	file path
  -INTERFLOW:          Simulate Interflow
	boolean
	Default: 1
  -T:               Mean Temperature
	floating point number
	Default: 18
  -TIMESPAN:           Timespan
	integer number
	Minimum: 1
	Maximum: 365
	Default: 30
  -R:               Rainfall
	floating point number
	Minimum: 0.000000
	Default: 200
  -I:               Rainfall Intensity
	floating point number
	Minimum: 0.000000
	Default: 20
  -Rn:                 Rainfall Duration
	integer number
	Minimum: 0
	Default: 20
  -KE_I_METHOD:        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:        Flow Depth (Actual Flow Velocity)
	floating point number
	Minimum: 0.000000
	Default: 0.005
  -CHANNELTRANSPORT:   Route Soil along Channel Network
	boolean
	Default: 0