Tool Flow Accumulation (Flow Tracing)

Flow tracing algorithms for calculations of flow accumulation and related parameters. These algorithms trace the flow of each cell in a DEM separately until it finally leaves the DEM or ends in a sink.
The Rho 8 implementation (Fairfield & Leymarie 1991) adopts the original algorithm only for the flow routing and will give quite different results.

References

Costa-Cabral, M. & Burges, S.J. (1994): Digital Elevation Model Networks (DEMON): a model of flow over hillslopes for computation of contributing and dispersal areas. Water Resources Research, 30:1681-1692. ResearchGate.
Fairfield, J. & Leymarie, P. (1991): Drainage networks from grid digital elevation models. Water Resources Research, 27:709-717.
Lea, N.L. (1992): An aspect driven kinematic routing algorithm. In: Parsons, A.J. & Abrahams, A.D. [Eds.], 'Overland Flow: hydraulics and erosion mechanics', London, 147-175.

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`	-	-
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`	-	-
Options	Grid system	Grid system	`PARAMETERS_GRID_SYSTEM`	-	-
	Step	Integer	`STEP`	For testing purposes. Only generate flow at cells with step distance (each step row/column).	Minimum: 0 Default: 1
	Flow Accumulation Unit	Choice	`FLOW_UNIT`	-	Available Choices: [0] number of cells [1] cell area Default: 1
	m_Method	Choice	`METHOD`	-	Available Choices: [0] Rho 8 [1] Kinematic Routing Algorithm [2] DEMON Default: 1
	Flow Correction	Boolean	`CORRECT`	-	Default: 1
	DEMON - Min. DQV	Floating point	`MINDQV`	DEMON - Minimum Drainage Quota Volume (DQV) for traced flow tubes	Minimum: 0.000000 Maximum: 1.000000 Default: 0.000000
(*) optional

Command-line

Usage: saga_cmd ta_hydrology 2 [-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>] [-STEP <num>] [-FLOW_UNIT <str>] [-METHOD <str>] [-CORRECT <str>] [-MINDQV <double>]
  -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)
  -STEP:<num>         	Step
	Integer
	Minimum: 0
	Default: 1
  -FLOW_UNIT:<str>    	Flow Accumulation Unit
	Choice
	Available Choices:
	[0] number of cells
	[1] cell area
	Default: 1
  -METHOD:<str>       	m_Method
	Choice
	Available Choices:
	[0] Rho 8
	[1] Kinematic Routing Algorithm
	[2] DEMON
	Default: 1
  -CORRECT:<str>      	Flow Correction
	Boolean
	Default: 1
  -MINDQV:<double>    	DEMON - Min. DQV
	Floating point
	Minimum: 0.000000
	Maximum: 1.000000
	Default: 0.000000