What are the "Extension Height" and "Backslope" in a channel subbassembly?

[Anonymous]

I have a question about Assemblies and corridors. I am currently working on a project in Africa, in which we have to design open gutters for stormwater management. I supposing the way to represent this in Civil 3D would be to use a Channel Assembly to create a corridor. The question that I have is, what exactly are the "Extension Height" and "Backslope"? What do they represent in the surface, once I create the corridor. How do they affect it?

Please see the picture below for a representation.

What exactly do the "Extension Height and "Backslope" lines represent? You can see them in the picture above, on top of the channel. When I change their properties, what will it change in the surface I create my corridor on?

[redtransitconsultants]

The right and left extension heights appear to be the distance above the attachment point. I would think this is provided if you need to build a berm outside of the channel. The backslope width and backslope slope would then be set to grade out from the extension calculation.

Setting all this values to 0 should eliminate these if not needed.