Flow Accumulation (Flow Tracing)

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

Description

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. doi:10.1029/93WR03512
Fairfield, J. & Leymarie, P. (1991): Drainage networks from grid digital elevation models. Water Resources Research, 27:709-717. doi:10.1029/90WR02658
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. doi:10.1201/b12648

Parameters

	Name	Type	Identifier	Description	Constraints
Input	Elevation	grid, input	`ELEVATION`	-	-
	Sink Routes	grid, input, optional	`SINKROUTE`	-	-
	Weights	grid, input, optional	`WEIGHTS`	-	-
	Sinks	grid, input, optional	`SINKS`	A grid indicating sink (terminal) cells. Cells with valid values (i.e. not NoData) act as sinks that capture all incoming flow and sediment and do not route anything downslope.	-
	Input for Mean over Catchment	grid, input, optional	`VAL_INPUT`	-	-
	Material for Accumulation	grid, input, optional	`ACCU_MATERIAL`	-	-
	Accumulation Target	grid, input	`ACCU_TARGET`	-	-
Output	Flow Accumulation	grid, output	`FLOW`	-	-
	Mean over Catchment	grid, output	`VAL_MEAN`	-	-
	Accumulated Material	grid, output, optional	`ACCU_TOTAL`	-	-
	Accumulated Material (Left Side)	grid, output, optional	`ACCU_LEFT`	-	-
	Accumulated Material (Right Side)	grid, output, optional	`ACCU_RIGHT`	-	-
Options	Grid System	grid system	`PARAMETERS_GRID_SYSTEM`	-	-
	Step	integer number	`STEP`	For testing purposes. Only generate flow at cells with step distance (each step row/column).	Minimum: 1 Default: 1
	Flow Accumulation Unit	choice	`FLOW_UNIT`	-	Available Choices: [0] number of cells [1] cell area Default: 1
	Method	choice	`METHOD`	-	Available Choices: [0] Rho 8 [1] Kinematic Routing Algorithm [2] DEMON Default: 1
	Flow Correction	boolean	`CORRECT`	-	Default: 1
	Minimum DQV	floating point number	`MINDQV`	DEMON - Minimum Drainage Quota Volume (DQV) for traced flow tubes	Minimum: 0.000000 Maximum: 1.000000 Default: 0.000000

Command Line


Usage: saga_cmd ta_hydrology 2 [-ELEVATION ] [-SINKROUTE ] [-WEIGHTS ] [-SINKS ] [-FLOW ] [-VAL_INPUT ] [-VAL_MEAN ] [-ACCU_MATERIAL ] [-ACCU_TARGET ] [-ACCU_TOTAL ] [-ACCU_LEFT ] [-ACCU_RIGHT ] [-STEP ] [-FLOW_UNIT ] [-METHOD ] [-CORRECT ] [-MINDQV ]
  -ELEVATION:       Elevation
	grid, input
  -SINKROUTE:       Sink Routes
	grid, input, optional
  -WEIGHTS:         Weights
	grid, input, optional
  -SINKS:           Sinks
	grid, input, optional
  -FLOW:            Flow Accumulation
	grid, output
  -VAL_INPUT:       Input for Mean over Catchment
	grid, input, optional
  -VAL_MEAN:        Mean over Catchment
	grid, output
  -ACCU_MATERIAL:   Material for Accumulation
	grid, input, optional
  -ACCU_TARGET:     Accumulation Target
	grid, input
  -ACCU_TOTAL:      Accumulated Material
	grid, output, optional
  -ACCU_LEFT:       Accumulated Material (Left Side)
	grid, output, optional
  -ACCU_RIGHT:      Accumulated Material (Right Side)
	grid, output, optional
  -STEP:            Step
	integer number
	Minimum: 1
	Default: 1
  -FLOW_UNIT:       Flow Accumulation Unit
	choice
	Available Choices:
	[0] number of cells
	[1] cell area
	Default: 1
  -METHOD:          Method
	choice
	Available Choices:
	[0] Rho 8
	[1] Kinematic Routing Algorithm
	[2] DEMON
	Default: 1
  -CORRECT:         Flow Correction
	boolean
	Default: 1
  -MINDQV:       Minimum DQV
	floating point number
	Minimum: 0.000000
	Maximum: 1.000000
	Default: 0.000000