SAGA-GIS Module Library Documentation (v2.3.0)

Module 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.

References:

Rho 8 (this implementation adopted the original algorithm only for the flow routing and will give quite different results):
- Fairfield, J. / Leymarie, P. (1991):
'Drainage networks from grid digital elevation models',
Water Resources Research, 27:709-717

Kinematic Routing Algorithm:
- 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

DEMON:
- 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

Parameters

 NameTypeIdentifierDescriptionConstraints
InputElevationGrid (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 TargetGrid (input)ACCU_TARGET--
OutputFlow AccumulationGrid (output)FLOW--
Mean over CatchmentGrid (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--
OptionsGrid systemGrid systemPARAMETERS_GRID_SYSTEMGrid system-
StepIntegerSTEP-Minimum: 1
Default: 1
Flow Accumulation UnitChoiceFLOW_UNIT-Available Choices:
[0] number of cells
[1] cell area
Default: 1
MethodChoiceMETHOD-Available Choices:
[0] Rho 8
[1] Kinematic Routing Algorithm
[2] DEMON
Default: 1
DEMON - Min. DQVFloating pointMINDQVDEMON - Minium Drainage Quota Volume (DQV) for traced flow tubesMinimum: 0.000000
Maximum: 1.000000
Default: 0.000000
Flow CorrectionBooleanCORRECT-Default: 0
(*) 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>] [-MINDQV <double>] [-CORRECT <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)
  -STEP:<num>         	Step
	Integer
	Minimum: 1
	Default: 1
  -FLOW_UNIT:<str>    	Flow Accumulation Unit
	Choice
	Available Choices:
	[0] number of cells
	[1] cell area
	Default: 1
  -METHOD:<str>       	Method
	Choice
	Available Choices:
	[0] Rho 8
	[1] Kinematic Routing Algorithm
	[2] DEMON
	Default: 1
  -MINDQV:<double>    	DEMON - Min. DQV
	Floating point
	Minimum: 0.000000
	Maximum: 1.000000
	Default: 0.000000
  -CORRECT:<str>      	Flow Correction
	Boolean
	Default: 0