Overland Flow Distance to Channel Network
- Author: O.Conrad (c) 2001-14
- Menu: Terrain Analysis | Channels
Description
This tool calculates overland flow distances to a channel network based on gridded digital elevation data and channel network information. The flow algorithm may be either Deterministic 8 (O'Callaghan & Mark 1984) or Multiple Flow Direction (Freeman 1991). Sediment Delivery Rates (SDR) according to Ali & De Boer (2010) can be computed optionally.
References
- Ali, K. F., De Boer, D. H. (2010): Spatially distributed erosion and sediment yield modeling in the upper Indus River basin. Water Resources Research, 46(8), W08504 doi:10.1029/2009WR008762.
- Freeman, G.T. (1991): Calculating catchment area with divergent flow based on a regular grid. Computers and Geosciences, 17:413-22. doi:10.1016/0098-3004(91)90048-I.
- Nobre, A.D., Cuartas, L.A., Hodnett, M., Renno, C.D., Rodrigues, G., Silveira, A., Waterloo, M., Saleska S. (2011): Height Above the Nearest Drainage - a hydrologically relevant new terrain model. Journal of Hydrology, Vol. 404, Issues 1-2, pp. 13-29, ISSN 0022-1694, 10.1016/j.jhydrol.2011.03.051. doi:10.1016/j.jhydrol.2011.03.051.
- O'Callaghan, J.F. & Mark, D.M. (1984): The extraction of drainage networks from digital elevation data. Computer Vision, Graphics and Image Processing, 28:323-344. doi:10.1016/S0734-189X(84)80011-0.
Parameters
| Name | Type | Identifier | Description | Constraints | |
|---|---|---|---|---|---|
| Input | Elevation | grid, input | ELEVATION | A grid that contains elevation data. | - |
| Channel Network | grid, input | CHANNELS | A grid providing information about the channel network. It is assumed that no-data cells are not part of the channel network. Vice versa all others cells are recognised as channel network members. | - | |
| Preferred Routing | grid, input, optional | ROUTE | Downhill flow is bound to preferred routing cells, where these are not no-data. Helps to model e.g. small ditches, that are not well represented in the elevation data. | - | |
| Fields | grid, input, optional | FIELDS | If set, output is given about the number of fields a flow path visits downhill. For D8 only. | - | |
| Manning-Strickler Coefficient | grid, input, optional | FLOW_K | Manning-Strickler coefficient for flow travel time estimation (reciprocal of Manning's Roughness Coefficient) | - | |
| Flow Depth | grid, input, optional | FLOW_R | flow depth [m] for flow travel time estimation | - | |
| Output | Overland Flow Distance | grid, output | DISTANCE | The overland flow distance in map units. It is assumed that the (vertical) elevation data use the same units as the (horizontal) grid coordinates. | - |
| Vertical Overland Flow Distance | grid, output | DISTVERT | This is the vertical component of the overland flow | - | |
| Horizontal Overland Flow Distance | grid, output | DISTHORZ | This is the horizontal component of the overland flow | - | |
| Flow Travel Time | grid, output, optional | TIME | flow travel time to channel expressed in hours based on Manning's Equation | - | |
| Sediment Yield Delivery Ratio | grid, output, optional | SDR | This is the horizontal component of the overland flow | - | |
| Fields Visited | grid, output | PASSES | Number of fields a flow path visits downhill starting at a cell. For D8 only. | - | |
| Options | Grid System | grid system | PARAMETERS_GRID_SYSTEM | - | - |
| Flow Algorithm | choice | METHOD | Choose a flow routing algorithm that shall be used for the overland flow distance calculation: - D8 - MFD | Available Choices: [0] D8 [1] MFD Default: 1 | |
| Boundary Cells | boolean | BOUNDARY | Take cells at the boundary of the DEM as channel. | Default: 0 | |
| Beta | floating point number | FLOW_B | catchment specific parameter for sediment delivery ratio calculation | Minimum: 0.000000 Default: 1.000000 | |
| Default | floating point number | FLOW_K_DEFAULT | default value if no grid has been selected | Minimum: 0.000000 Default: 20.000000 | |
| Default | floating point number | FLOW_R_DEFAULT | default value if no grid has been selected | Minimum: 0.000000 Default: 0.050000 |
Command Line
Usage: saga_cmd ta_channels 4 [-ELEVATION] [-CHANNELS ] [-ROUTE ] [-DISTANCE ] [-DISTVERT ] [-DISTHORZ ] [-TIME ] [-SDR ] [-FIELDS ] [-PASSES ] [-METHOD ] [-BOUNDARY ] [-FLOW_B ] [-FLOW_K ] [-FLOW_K_DEFAULT ] [-FLOW_R ] [-FLOW_R_DEFAULT ] -ELEVATION: Elevation grid, input -CHANNELS: Channel Network grid, input -ROUTE: Preferred Routing grid, input, optional -DISTANCE: Overland Flow Distance grid, output -DISTVERT: Vertical Overland Flow Distance grid, output -DISTHORZ: Horizontal Overland Flow Distance grid, output -TIME: Flow Travel Time grid, output, optional -SDR: Sediment Yield Delivery Ratio grid, output, optional -FIELDS: Fields grid, input, optional -PASSES: Fields Visited grid, output -METHOD: Flow Algorithm choice Available Choices: [0] D8 [1] MFD Default: 1 -BOUNDARY: Boundary Cells boolean Default: 0 -FLOW_B: Beta floating point number Minimum: 0.000000 Default: 1.000000 -FLOW_K: Manning-Strickler Coefficient grid, input, optional -FLOW_K_DEFAULT: Default floating point number Minimum: 0.000000 Default: 20.000000 -FLOW_R: Flow Depth grid, input, optional -FLOW_R_DEFAULT: Default floating point number Minimum: 0.000000 Default: 0.050000