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.
Here E is the supply. Tout at each grid cell becomes Tin for downslope grid cells and is reported as Transport limited accumulation (tla). D is deposition (tdep). The function provides the option to evaluate concentration of a compound (contaminant) adhered to the transported substance. This is evaluated as follows:
Where Lin is the total incoming compound loading and Cin and Tin refer to the Concentration and Transport entering from each upslope grid cell.
If
else
where Cs is the concentration supplied locally and the difference in the second term on the right represents the additional supply from the local grid cell. Then,
Cout at each grid cell comprises is the concentration grid output from this function.
If the outlets shapefile is used the tool only evaluates that part of the domain that contributes flow to the locations given by the shapefile.
Transport limited accumulation is useful for modeling erosion and sediment delivery, including the spatial dependence of sediment delivery ratio and contaminant that adheres to sediment.
Optional.
This optional input is a point shapefile defining outlets of interest. If this file is used, the tool will only evaluate the area upslope of these outlets.
This option 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.
Default: True
processing.runalg('taudem:dinfinitytransportlimitedaccumulation', dinf_flow_dir_grid, supply_grid, capacity_grid, outlets_shape, edge_contam, transp_lim_accum_grid, deposition_grid)