When running an encroachment analysis on a model with a normal depth boundary condition do you input a known water surface elevation at 1 foot higher than the natural run for the boundary condition of the encroachment profile?
Yes, you would normally want to start the encroached section with a water surface one foot higher. If the encroachment goes all the way to the downstream end, then one foot higher at the boundary. If the encroachment does not go all the way down, then the one foot higher would usually be whereever the encroachment starts (you can force a known water surface at any given cross section).