Tool Flow Accumulation (Recursive)

Recursive upward processing of cells for calculation of flow accumulation and related parameters. This set of algorithms processes recursively all upwards connected cells until each cell of the DEM has been processed.

Flow routing methods provided by this tool:

Deterministic 8 (aka D8, O'Callaghan & Mark 1984)
Rho 8 (Fairfield & Leymarie 1991)
Multiple Flow Direction (Freeman 1991, Quinn et al. 1991)
Deterministic Infinity (Tarboton 1997)

References

Fairfield, J. & Leymarie, P. (1991): Drainage networks from grid digital elevation models. Water Resources Research, 27:709-717.
Freeman, G.T. (1991): Calculating catchment area with divergent flow based on a regular grid. Computers and Geosciences, 17:413-22.
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.
Quinn, P.F., Beven, K.J., Chevallier, P. & Planchon, O. (1991): The prediction of hillslope flow paths for distributed hydrological modelling using digital terrain models. Hydrological Processes, 5:59-79. ResearchGate.
Tarboton, D.G. (1997): A new method for the determination of flow directions and upslope areas in grid digital elevation models. Water Resources Research, Vol.33, No.2, p.309-319. Wiley.

Author: O.Conrad (c) 2001
Menu: Terrain Analysis|Hydrology|Flow Accumulation

Parameters

	Name	Type	Identifier	Description	Constraints
Input	Elevation	Grid (input)	`ELEVATION`	-	-
	Sink Routes (*)	Grid (optional input)	`SINKROUTE`	-	-
	Weights (*)	Grid (optional input)	`WEIGHTS`	-	-
	Input for Mean over Catchment (*)	Grid (optional input)	`VAL_INPUT`	-	-
	Material for Accumulation (*)	Grid (optional input)	`ACCU_MATERIAL`	-	-
	Accumulation Target	Grid (input)	`ACCU_TARGET`	-	-
	Target Areas (*)	Grid (optional input)	`TARGETS`	-	-
Output	Flow Accumulation	Grid (output)	`FLOW`	-	-
	Mean over Catchment	Grid (output)	`VAL_MEAN`	-	-
	Accumulated Material (*)	Grid (optional output)	`ACCU_TOTAL`	-	-
	Accumulated Material (Left Side) (*)	Grid (optional output)	`ACCU_LEFT`	-	-
	Accumulated Material (Right Side) (*)	Grid (optional output)	`ACCU_RIGHT`	-	-
	Flow Path Length (*)	Grid (optional output)	`FLOW_LENGTH`	average distance that a cell's accumulated flow travelled	-
	Loss through Negative Weights (*)	Grid (optional output)	`WEIGHT_LOSS`	when using weights without support for negative flow: output of the absolute amount of negative flow that occurred	-
Options	Grid system	Grid system	`PARAMETERS_GRID_SYSTEM`	-	-
	Flow Accumulation Unit	Choice	`FLOW_UNIT`	-	Available Choices: [0] number of cells [1] cell area Default: 1
	Method	Choice	`METHOD`	-	Available Choices: [0] Deterministic 8 [1] Rho 8 [2] Deterministic Infinity [3] Multiple Flow Direction Default: 3
	Convergence	Floating point	`CONVERGENCE`	Convergence factor for Multiple Flow Direction Algorithm (Freeman 1991)	Minimum: 0.000000 Default: 1.100000
	Prevent Negative Flow Accumulation	Boolean	`NO_NEGATIVES`	when using weights: do not transport negative flow, set it to zero instead; useful e.g. when accumulating measures of water balance.	Default: 1
(*) optional

Command-line

Usage: saga_cmd ta_hydrology 1 [-ELEVATION <str>] [-SINKROUTE <str>] [-WEIGHTS <str>] [-FLOW <str>] [-VAL_INPUT <str>] [-VAL_MEAN <str>] [-ACCU_MATERIAL <str>] [-ACCU_TARGET <str>] [-ACCU_TOTAL <str>] [-ACCU_LEFT <str>] [-ACCU_RIGHT <str>] [-FLOW_UNIT <str>] [-TARGETS <str>] [-FLOW_LENGTH <str>] [-WEIGHT_LOSS <str>] [-METHOD <str>] [-CONVERGENCE <double>] [-NO_NEGATIVES <str>]
  -ELEVATION:<str>     	Elevation
	Grid (input)
  -SINKROUTE:<str>     	Sink Routes
	Grid (optional input)
  -WEIGHTS:<str>       	Weights
	Grid (optional input)
  -FLOW:<str>          	Flow Accumulation
	Grid (output)
  -VAL_INPUT:<str>     	Input for Mean over Catchment
	Grid (optional input)
  -VAL_MEAN:<str>      	Mean over Catchment
	Grid (output)
  -ACCU_MATERIAL:<str> 	Material for Accumulation
	Grid (optional input)
  -ACCU_TARGET:<str>   	Accumulation Target
	Grid (input)
  -ACCU_TOTAL:<str>    	Accumulated Material
	Grid (optional output)
  -ACCU_LEFT:<str>     	Accumulated Material (Left Side)
	Grid (optional output)
  -ACCU_RIGHT:<str>    	Accumulated Material (Right Side)
	Grid (optional output)
  -FLOW_UNIT:<str>     	Flow Accumulation Unit
	Choice
	Available Choices:
	[0] number of cells
	[1] cell area
	Default: 1
  -TARGETS:<str>       	Target Areas
	Grid (optional input)
  -FLOW_LENGTH:<str>   	Flow Path Length
	Grid (optional output)
  -WEIGHT_LOSS:<str>   	Loss through Negative Weights
	Grid (optional output)
  -METHOD:<str>        	Method
	Choice
	Available Choices:
	[0] Deterministic 8
	[1] Rho 8
	[2] Deterministic Infinity
	[3] Multiple Flow Direction
	Default: 3
  -CONVERGENCE:<double>	Convergence
	Floating point
	Minimum: 0.000000
	Default: 1.100000
  -NO_NEGATIVES:<str>  	Prevent Negative Flow Accumulation
	Boolean
	Default: 1