Simulating Adding RipRap

I'm working on a project that involves me simulating the effects of adding riprap to an existing surface in 4 areas for a project that already has P&P's and X-Sections made. The steps that I'm currently trying are: 1) Take the Existing Surface in the X-Sections, trace a p-line over the Existing surface, offset that p-line 2.5', extend the p-line to the flowline of the channel, square off the top (this should give me what the extents of the riprap should be).2) cropping the surface, 3) Raising each surface 2.5 feet, 4) creating a feature line, giving the elevations of the existing ground of the creek, then adding the feature line to its respective area. 5) Cut X-Sections. 6) Check the cut X-Sections with what the "Proposed Surface" should be close to looking like from (1). If anyone has any suggestions or another way of achieving what I'm trying to accomplish, it would be greatly appreciated.


James A. Stretesky