Tool Slope Limited Flow Accumulation
Flow accumulation is calculated as upslope contributing (catchment) area using the multiple flow direction approach of Freeman (1991). For this tool the approach has been modified to limit the flow portion routed through a cell depending on the local slope. If a cell is not inclined, no flow is routed through it at all. With increasing slopes the portion of flow routed through a cell becomes higher. Cells with slopes greater than a specified slope threshold route their entire accumulated flow downhill.
References
- Freeman, G.T. (1991): Calculating catchment area with divergent flow based on a regular grid. Computers and Geosciences, 17:413-22.
- Author: O.Conrad (c) 2014
- Menu: Terrain Analysis|Hydrology|Flow Accumulation
Parameters
| Name | Type | Identifier | Description | Constraints | |
|---|---|---|---|---|---|
| Input | Elevation | Grid, input | DEM | - | - |
| Weight (*) | Grid, input, optional | WEIGHT | - | - | |
| Output | Flow Accumulation | Grid, output | FLOW | - | - |
| Options | Grid System | Grid system | PARAMETERS_GRID_SYSTEM | - | - |
| Slope Minimum | Floating point | SLOPE_MIN | Assume a given minimum slope for each cell. | Minimum: 0.000000 Default: 0.000000 | |
| Slope Threshold | Floating point | SLOPE_MAX | Slope threshold, given as degree, above which flow transport is unlimited. | Minimum: 0.000000 Maximum: 90.000000 Default: 5.000000 | |
| Use Flow Threshold | Boolean | B_FLOW | - | Default: 0 | |
| Flow Threshold | Value range | T_FLOW | Flow threshold, given as amount of cells, above which flow transport is unlimited. Ignored if range equals zero. | - | |
| (*) optional | |||||
Command-line
Usage: saga_cmd ta_hydrology 26 [-DEM <str>] [-WEIGHT <str>] [-FLOW <str>] [-SLOPE_MIN <double>] [-SLOPE_MAX <double>] [-B_FLOW <str>] [-T_FLOW_MIN <double>] [-T_FLOW_MAX <double>] -DEM:<str> Elevation Grid, input -WEIGHT:<str> Weight Grid, input, optional -FLOW:<str> Flow Accumulation Grid, output -SLOPE_MIN:<double> Slope Minimum Floating point Minimum: 0.000000 Default: 0.000000 -SLOPE_MAX:<double> Slope Threshold Floating point Minimum: 0.000000 Maximum: 90.000000 Default: 5.000000 -B_FLOW:<str> Use Flow Threshold Boolean Default: 0 -T_FLOW_MIN:<double> Flow Threshold Value range -T_FLOW_MAX:<double> Flow Threshold Value range