SAGA-GIS Tool Library Documentation (v7.8.2)

Tool Quasi-Dynamic Flow Accumulation

This tool estimates the flow distribution at a specified time after a rainfall event. It is based on a standard flow accumulation calculation (e.g. O'Callaghan & Mark 1984, Freeman 1991) that has an additional function to accumulate the flow travel time. Final flow accumulation becomes that part of the total flow through that corresponds to the portion of flow travel time that exceeds the targeted time. The travel time is estimated with the empirical Manning equation (e.g. Dingman 1994, Freeman et al. 1998, Manning 1891).


References


Parameters

 NameTypeIdentifierDescriptionConstraints
InputElevationGrid, inputDEM[m]-
Manning-Strickler Coefficient (*)Grid, input, optionalFLOW_KManning-Strickler coefficient for flow travel time estimation (reciprocal of Manning's Roughness Coefficient)-
OutputFlow AccumulationGrid, outputFLOW_ACC[mm]-
Flow Through (*)Grid, output, optionalFLOW--
Flow Travel Time (*)Grid, output, optionalTIME_MEAN--
Flow Concentration (*)Grid, output, optionalTIME_CONC--
Flow Velocity (*)Grid, output, optionalVELOCITY--
OptionsGrid SystemGrid systemPARAMETERS_GRID_SYSTEM--
DefaultFloating pointFLOW_K_DEFAULTdefault value if no grid has been selectedMinimum: 0.000000
Default: 20.000000
TimeFloating pointTIMEminutesMinimum: 0.001000
Default: 5.000000
Flow RoutingChoiceROUTING-Available Choices:
[0] D8
[1] MFD
Default: 1
Flow DepthChoiceFLOW_DEPTH-Available Choices:
[0] constant
[1] dynamic
Default: 1
Constant Flow DepthFloating pointFLOW_CONST[mm]Minimum: 0.000000
Default: 10.000000
ResetBooleanRESETResets flow accumulation raster.Default: 1
RainFloating pointRAINThe flow portion [mm] added to each raster cell before simulation starts.Minimum: 0.000000
Default: 10.000000
(*) optional

Command-line

Usage: saga_cmd sim_hydrology 8 [-DEM <str>] [-FLOW_K <str>] [-FLOW_K_DEFAULT <double>] [-FLOW_ACC <str>] [-FLOW <str>] [-TIME_MEAN <str>] [-TIME_CONC <str>] [-VELOCITY <str>] [-TIME <double>] [-ROUTING <str>] [-FLOW_DEPTH <str>] [-FLOW_CONST <double>] [-RESET <str>] [-RAIN <double>]
  -DEM:<str>              	Elevation
	Grid, input
  -FLOW_K:<str>           	Manning-Strickler Coefficient
	Grid, input, optional
  -FLOW_K_DEFAULT:<double>	Default
	Floating point
	Minimum: 0.000000
	Default: 20.000000
  -FLOW_ACC:<str>         	Flow Accumulation
	Grid, output
  -FLOW:<str>             	Flow Through
	Grid, output, optional
  -TIME_MEAN:<str>        	Flow Travel Time
	Grid, output, optional
  -TIME_CONC:<str>        	Flow Concentration
	Grid, output, optional
  -VELOCITY:<str>         	Flow Velocity
	Grid, output, optional
  -TIME:<double>          	Time
	Floating point
	Minimum: 0.001000
	Default: 5.000000
  -ROUTING:<str>          	Flow Routing
	Choice
	Available Choices:
	[0] D8
	[1] MFD
	Default: 1
  -FLOW_DEPTH:<str>       	Flow Depth
	Choice
	Available Choices:
	[0] constant
	[1] dynamic
	Default: 1
  -FLOW_CONST:<double>    	Constant Flow Depth
	Floating point
	Minimum: 0.000000
	Default: 10.000000
  -RESET:<str>            	Reset
	Boolean
	Default: 1
  -RAIN:<double>          	Rain
	Floating point
	Minimum: 0.000000
	Default: 10.000000