Create 3D by Slope to Target

I am working on modeling some ponds and I have a situation where I have a standard retention pond that sits next to a flood plain compensation (FPC) pond. What I would like to do is half accomplished by the Create 3D by Slope to Target.

I have the outside of the FPC which is 5' off the R/W line and at existing ground. I would like that to slope down at 1:3 to an elevation of 103. I can create this line using the above mentioned tool, but it only creates that line in the 3D view and not in the plan view. Ideally I would like this line to be created in plan view with a profile attached to it locked at 103 and having the horizontal element controlled by the 1:3 slope.

What I could do is just use the line create by Create 3D by Slope to Target as a guideline and then draw in a regular offset from the top of bank to normalize the slope. This works fine if the tie down point does not vary all that much and if I dont need to change anything, but ideally this pond model would be fully dynamic.

Is there any tool that can do something like that?