SAGA-GIS Tool Library Documentation (v7.8.2)

Tool Overland Flow Distance to Channel Network

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


Parameters

 NameTypeIdentifierDescriptionConstraints
InputElevationGrid, inputELEVATIONA grid that contains elevation data.-
Channel NetworkGrid, inputCHANNELSA 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, optionalROUTEDownhill 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, optionalFIELDSIf set, output is given about the number of fields a flow path visits downhill. For D8 only.-
Manning-Strickler Coefficient (*)Grid, input, optionalFLOW_KManning-Strickler coefficient for flow travel time estimation (reciprocal of Manning's Roughness Coefficient)-
Flow Depth (*)Grid, input, optionalFLOW_Rflow depth [m] for flow travel time estimation-
OutputOverland Flow DistanceGrid, outputDISTANCEThe 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 DistanceGrid, outputDISTVERTThis is the vertical component of the overland flow-
Horizontal Overland Flow DistanceGrid, outputDISTHORZThis is the horizontal component of the overland flow-
Flow Travel Time (*)Grid, output, optionalTIMEflow travel time to channel expressed in hours based on Manning's Equation-
Sediment Yield Delivery Ratio (*)Grid, output, optionalSDRThis is the horizontal component of the overland flow-
Fields VisitedGrid, outputPASSESNumber of fields a flow path visits downhill starting at a cell. For D8 only.-
OptionsGrid SystemGrid systemPARAMETERS_GRID_SYSTEM--
Flow AlgorithmChoiceMETHODChoose a flow routing algorithm that shall be used for the overland flow distance calculation: - D8 - MFDAvailable Choices:
[0] D8
[1] MFD
Default: 1
Boundary CellsBooleanBOUNDARYTake cells at the boundary of the DEM as channel.Default: 0
BetaFloating pointFLOW_Bcatchment specific parameter for sediment delivery ratio calculationMinimum: 0.000000
Default: 1.000000
DefaultFloating pointFLOW_K_DEFAULTdefault value if no grid has been selectedMinimum: 0.000000
Default: 20.000000
DefaultFloating pointFLOW_R_DEFAULTdefault value if no grid has been selectedMinimum: 0.000000
Default: 0.050000
(*) optional

Command-line

Usage: saga_cmd ta_channels 4 [-ELEVATION <str>] [-CHANNELS <str>] [-ROUTE <str>] [-DISTANCE <str>] [-DISTVERT <str>] [-DISTHORZ <str>] [-TIME <str>] [-SDR <str>] [-FIELDS <str>] [-PASSES <str>] [-METHOD <str>] [-BOUNDARY <str>] [-FLOW_B <double>] [-FLOW_K <str>] [-FLOW_K_DEFAULT <double>] [-FLOW_R <str>] [-FLOW_R_DEFAULT <double>]
  -ELEVATION:<str>        	Elevation
	Grid, input
  -CHANNELS:<str>         	Channel Network
	Grid, input
  -ROUTE:<str>            	Preferred Routing
	Grid, input, optional
  -DISTANCE:<str>         	Overland Flow Distance
	Grid, output
  -DISTVERT:<str>         	Vertical Overland Flow Distance
	Grid, output
  -DISTHORZ:<str>         	Horizontal Overland Flow Distance
	Grid, output
  -TIME:<str>             	Flow Travel Time
	Grid, output, optional
  -SDR:<str>              	Sediment Yield Delivery Ratio
	Grid, output, optional
  -FIELDS:<str>           	Fields
	Grid, input, optional
  -PASSES:<str>           	Fields Visited
	Grid, output
  -METHOD:<str>           	Flow Algorithm
	Choice
	Available Choices:
	[0] D8
	[1] MFD
	Default: 1
  -BOUNDARY:<str>         	Boundary Cells
	Boolean
	Default: 0
  -FLOW_B:<double>        	Beta
	Floating point
	Minimum: 0.000000
	Default: 1.000000
  -FLOW_K:<str>           	Manning-Strickler Coefficient
	Grid, input, optional
  -FLOW_K_DEFAULT:<double>	Default
	Floating point
	Minimum: 0.000000
	Default: 20.000000
  -FLOW_R:<str>           	Flow Depth
	Grid, input, optional
  -FLOW_R_DEFAULT:<double>	Default
	Floating point
	Minimum: 0.000000
	Default: 0.050000