How to automate a process to find the banks of a stream or river?

[GinaKiani]

Hello
I am a pretty novice user taking a USC GIST Master Certification with a final project to use GIS to solve a spatial problem
My model has several steps and I am stuck on trying to automate a process to find the banks of an area where the flow accumulation is greatest
Does anyone have any ideas which tool or process would be used to find the banks or highest elevation around a stream or river?
I am working with a DEM layer and though I may be able to visually identify the bank areas, is there a way to automate a polygon for the river or stream that encloses the banks of the stream as the outer border of the polygon
I really appreciate any help and input for solutions to this objective
Thanks so much!!

[BikashSherchan]

My quick suggestion is to go for HEC-GeoRAS which is an ArcGIS extension and freely available to download. You can define bank lines and flood boundaries together with cross-sections and export to HEC-RAS as a geometry file with which you can do steady or unsteady flow analysis according to your requirements.

Good Luck
Bikash

[MarkBoucher]

If your DEM grids are small/fine enough to distinguish the flatter bottom and floodplain from the banks, and you have a polyline defining the stream/river, it seems you would be able to create a slope raster from the DEM, buffer the stream and use the buffer to extract the slope around the stream/river and determine a slope that would distinguish the banks from the stream/river bed. Then you could use the Con() function to ID the grids with slopes w/in a certain range or above a certain value and this would ID the banks.

[TroyBungard]

I realize this is an old post - but I need a similar function.  Working for our County Surveyor, we have several 'open ditch' drains that are county regulated.  We have a 75ft easement from top of bank.  So naturally, finding top of bank is important.  I haven't found a way to automate yet, as I am self taught on the software, but in ArcGIS Pro, I used the lidar dem of our county and generated a slope map percent raster?  anyway, it's a layer that is shaded based on the slope gradient.  the steeper the bank, the darker the shading - so all I had to do after that was essentially 'trace' the map.  I created a top of bank layer shape file - turned on my regulated drain layer which is centerline of all of our drains - (open and tile).  wherever there was an open drain, I had the slope layer on, and visually, I could see where the slope of the ditch leveled out - as a color change from dark to light.  as well the centerline or 'flow' area of the ditch was also light colored.  So I simply drew in polylines on my top of bank layer.  I made sure to pay attention to how I drew them in, so that I could do a buffer - offsetting Right - for every line in the layer.  I then had a right of way layer shaded with my 75ft buffer, from top of bank.  I only wish I could get the software to draw in the top of bank line for me.