Soil erosion modelling with a modified MMF (Morgan-Morgan-Finney) model (Morgan & Duzant 2008).
This module is called MMF-SAGA because some things have been implemented differently compared to the original publication. The most important are:
| Name | Type | Identifier | Description | Constraints |
Input | Digital Terrain Model | Grid (input) | DTM | DTM, digital terrain model [m] | - |
Slope | Grid (input) | S | S, slope [rad] | - |
Channel Network (*) | Grid (optional input) | CHANNEL | Channel network, all other cells NoData | - |
Permament Interception | Grid (input) | PI | PI, permanent interception expressed as the proportion [between 0-1] of rainfall | - |
Canopy Cover | Grid (input) | CC | CC, canopy cover expressed as a portion [between 0-1] of the soil surface protected by vegetation or crop | - |
Plant Height | Grid (input) | PH | PH, plant height [m], representing the effective height from which raindrops fall from the crop or vegetation | - |
Ratio Evapotranspiration | Grid (input) | EtEo | Et/Eo, ratio of actual to potential evapotranspiration | - |
Ground cover | Grid (input) | GC | GC, Ground cover expressed as a portion [between 0-1] of the soil surface protected by vegetation or crop cover on the ground | - |
Diameter plant elements | Grid (input) | D | D, Average diameter [m] of the individual plants elements (stem, leaves) at the ground surface | - |
Number plant elements | Grid (input) | NV | NV, Number of plant elements per unit area [number/unit area] at the ground surface | - |
Soil moisture (at FC) | Grid (input) | MS | MS, Soil moisture at field capacity [% w/w] | - |
Bulk density top layer | Grid (input) | BD | BD, Bulk density of the top layer [Mg/m3] | - |
Effective hydrological depth | Grid (input) | EHD | EHD, Effective hydrological depth of the soil [m] | - |
Sat. lateral permeability | Grid (input) | LP | LP, Saturated lateral permeability of the soil [m/day] | - |
Percentage clays | Grid (input) | PER_C | c, Percentage clays [%] | - |
Percentage silt | Grid (input) | PER_Z | z, Percentage silt [%] | - |
Percentage sand | Grid (input) | PER_S | s, Percentage sand [%] | - |
Percentage rock fragments | Grid (input) | ST | ST, Percentage rock fragments on the soil surface [%] | - |
Surface roughness | Grid (input) | RFR | RFR, Surface roughness [cm/m] | - |
Meteorological data (*) | Table (optional input) | TAB_METEO | Meteorological data for multiple timestep modelling [model step (day); temperature (Celsius); rainfall (mm), rainfall intensity (mm/h); rainfall duration (day); timespan (days)] | - |
Output | Interflow (*) | Grid (optional output) | IF | IF | - |
Mean runoff | Grid (output) | Q | Q, estimation of mean runoff [mm] | - |
Mean soil loss | Grid (output) | SL | SL, estimation of mean soil loss [kg] | - |
Effective Rainfall | Grid (output) | Rf | Rf | - |
Total Kinetic Energy | Grid (output) | KE | KE | - |
Soil moisture storage capacity | Grid (output) | Rc | Rc | - |
Transport Capacity Clay | Grid (output) | TCc | TCc | - |
Transport Capacity Silt | Grid (output) | TCz | TCz | - |
Transport Capacity Sand | Grid (output) | TCs | SLs | - |
Available Clay | Grid (output) | Gc | Gc | - |
Available Silt | Grid (output) | Gz | Gz | - |
Available Sand | Grid (output) | Gs | Gs | - |
Sediment Balance Clay | Grid (output) | SLc | SLc | - |
Sediment Balance Silt | Grid (output) | SLz | SLz | - |
Sediment Balance Sand | Grid (output) | SLs | SLs | - |
Transport Condition Clay | Grid (output) | TCONDc | Sediment Limited [0], Transport Limited (SL = TC) [1], Transport Limited (SL = G) [2] | - |
Transport Condition Silt | Grid (output) | TCONDz | Sediment Limited [0], Transport Limited (SL = TC) [1], Transport Limited (SL = G) [2] | - |
Transport Condition Sand | Grid (output) | TCONDs | Sediment Limited [0], Transport Limited (SL = TC) [1], Transport Limited (SL = G) [2] | - |
Upslope Flow Width | Grid (output) | W_up | W_up | - |
Options | Output file path | File path | OUT_PATH | Full path to the directory for the output grids of each model step | - |
Simulate Interflow | Boolean | INTERFLOW | Simulate interflow | Default: 1 |
Mean temperature | Floating point | T | T, mean temperature [degree C] | Default: 18.000000 |
Timespan (days) | Integer | TIMESPAN | The number of days to model. | Minimum: 1 Maximum: 365 Default: 30 |
Rainfall | Floating point | R | R, height of precipitation in timespan [mm] | Default: 200.000000 |
Rainfall intensity | Floating point | I | I, rainfall intensity [mm/h] | Default: 20.000000 |
Rainfall Duration | Floating point | Rn | Rn, number of rain days in timespan [-] | Default: 20.000000 |
Relationship KE - I | Choice | KE_I_METHOD | 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 | FLOWD_VA | The 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 Network | Boolean | CHANNELTRANSPORT | Route soil loss along channel network to outlet | Default: 0 |
(*) optional |