D-Infinity Transport Limited Accumulation

Title  D-Infinity Transport Limited Accumulation

Summary

This function is designed to calculate the transport and deposition of a substance (e.g. sediment) that may be limited by both supply and the capacity of the flow field to transport it. This function accumulates substance flux (e.g. sediment transport) subject to the rule that transport out of any grid cell is the minimum between supply and transport capacity, Tcap. The total supply at a grid cell is calculated as the sum of the transport in from upslope grid cells, Tin, plus the local supply contribution, E (e.g. erosion). This function also outputs deposition, D, calculated as total supply minus actual transport.


Usage

Command Prompt Syntax:

mpiexec -n <number of processes> DinfTransLimAccum -ang <angfile> -tsup <tsupfile> -tc <tcfile> [ -cs <csfile> -ctpt <ctptfile> ] -tla <tlafile> -tdep <tdepfile> [ -o <outletfile>] [ -nc] [-lyrname <layer name>] [ -lyrno <layer number>]

angfile: Dinf flow direction input grid

tsupfile: Input transport supply grid

tcfile:Input transport capacity grid

csfile:Input concentration grid (optional)

ctptfile:Output concentration grid (optional)

tlafile:Output transport limited accumulation grid

tdepfile:Output deposition grid

outletfile: input outlets file (OGR readable dataset)

nc: Flag for edge contamination

layer name: OGR layer name if outlets are not the first layer in outletfile (optional)

layer number: OGR layer number if outlets are not the first layer in outletfile (optional)

Layer name and layer number should not both be specified.


Syntax

DInfTransportLimited (Input_D-Infinity_Flow_Direction_Grid, Input_Supply_Grid, Input_Transport_Capacity_Grid, {Input_Concentration_Grid}, {Input_Outlets}, Check_for_Edge_Contamination, Input_Number_of_Processes, Output_Transport_Limited_Accumulation_Grid, Output_Deposition_Grid, {Output_Concentration_Grid})

Parameter Explanation Data Type
Input_D-Infinity_Flow_Direction_Grid Dialog Reference

A grid giving flow direction by the D-infinity method. Flow direction is measured in radians, counter clockwise from east. This can be created by the tool D-Infinity Flow Directions . The algorithm is described in Tarboton, D. G., (1997), "A New Method for the Determination of Flow Directions and Contributing Areas in Grid Digital Elevation Models," Water Resources Research, 33(2): 309-319.

 Raster Layer
Input_Supply_Grid Dialog Reference

A grid giving the supply (loading) of material to a transport limited accumulation function. In the application to erosion, this grid would give the erosion detachment, or sediment supplied at each grid cell.

 Raster Layer
Input_Transport_Capacity_Grid Dialog Reference

A grid giving the transport capacity at each grid cell for the transport limited accumulation function. In the application to erosion this grid would give the transport capacity of the carrying flow.

 Raster Layer
Input_Concentration_Grid (Optional) Dialog Reference

A grid giving the concentration of a compound of interest in the supply to the transport limited accumulation function. In the application to erosion, this grid would give the concentration of say phosphorous adhered to the eroded sediment.

 Raster Layer
Input_Outlets (Optional) Dialog Reference

This optional input is a point feature defining outlets of interest. If this input is used, the tool will only evaluate the area upslope of these outlets.

 Feature Layer
Check_for_Edge_Contamination Dialog Reference

This checkbox determines whether the tool should check for edge contamination. Edge contamination is defined as the possibility that a value may be underestimated due to grid cells outside of the domain not being considered when determining the result. This occurs when drainage is inwards from the boundaries or areas with no data values for elevation. The algorithm recognizes this possibility and reports no data for the result. It is common to see streaks of no data values extending inwards from boundaries along flow paths that enter the domain at a boundary. This is the desired effect, and indicates that values for these grid cells is unknown due to it being dependent on terrain outside of the available data. Edge contamination checking may be overridden in cases where you know it is not an issue, or want to ignore the problems, if for example, the DEM has been clipped along a watershed outline.

 Boolean
Input_Number_of_Processes Dialog Reference

This input indicates the number of stripes that the domain will be divided into and the number of MPI parallel processes that will be spawned to evaluate each piece of the domain.

 Long
Output_Transport_Limited_Accumulation_Grid Dialog Reference

This grid is the weighted accumulation of supply accumulated respecting the limitations in transport capacity and reports the transport rate calculated by accumulating the substance flux subject to the rule that the transport out of any grid cell is the minimum of the total supply (local supply plus transport in) to that grid cell and the transport capacity.

 Raster Dataset
Output_Deposition_Grid Dialog Reference

A grid giving the deposition resulting from the transport limited accumulation. This is the residual from the transport in to each grid cell minus the transport capacity out of the grid cell. The deposition grid is calculated as the transport in + the local supply - the tranport out.

 Raster Dataset
Output_Concentration_Grid (Optional) Dialog Reference

If an input concentation in supply grid is given, then this grid is also output and gives the concentration of a compound (contaminant) adhered or bound to the transported substance (e.g. sediment) is calculated.

 Raster Dataset

Code Samples

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