Hello,
I am modeling a long culvert that bends and expands in width and then contracts in widths while the bottom has a slope to it and the low chord does not slope. I am modeling this as cross sections with lids but need to fully understand how the manning’s n value gets applied to the lids. In existing conditions, the culvert is concrete on all sides so no problems. In proposed I am proposing a depressed culvert with fish baffles so want the sides and tops to be concrete with the bottom a higher manning’s n.
So, when I place a lid, where is it pulling the manning’s n value from for the lid?