Alluvial channels

Hi everyone,

How would I go about selectively modelling active alluvial channels within the upper alluvial/colluvial layer of my model.

In my drilling data the alluvial material is just logged as a single unit but I do have GIS layers that I can use to delineate the channel margins. I also have a high res DEM as the top of my model which shows these channels very clearly.


Essentially all I want to do is differentiate these channels within my upper alluvial layer as a separate surface.


I’ve tried creating an erosional surface with the channel polygon as the basis but this doesn’t work.


Is there a typical way that this situation should be approached?