Thank you so much…
I ran a quick test. First, with only one cross-section near the change in roughness with n = 0.04, where the channel changed from concrete to grass. In the other one, I had two cross-sections. One XSec with 0.015 where the concrete ends, another one 1 ft downstream of it for the beginning of grass channel with n = 0.04.
The resultant water surface profile for both scenarios are identical. Any idea?
Thanks again…