I am trying to represent de equation of Mahoney et al. (2018) https://www.sciencedirect.com/science/article/abs/pii/S0022169418302877

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Where Si is the slope in the cell i, ΣSup is is the sum of the slopes of each cell upstream of cell i and N is representative of the number of upstream cells flowing into cell i, determined via the Flow Accumulation tool. They say that this is determined by weighting the flow accumulation raster by the slope raster, but I don't localize the way to solve with a raster that represent the sum of the upstream slopes.

Is this possible or it is necesary more steps to solve?

  • In ArcGis and TauDEM dialogs of flow accumulation has optional WEIGHT raster.
    – FelixIP
    Commented Jan 7, 2022 at 19:09

1 Answer 1


Finally, I got a solution through SAGA independently of Qgis, using the function "Catchment area (parallel)" or "Flow accumulation (top-down)".

This is achieved by inserting the filled DEM as 'elevation' and the slope raster layer as 'Accumulated material'

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