HEC-RAS has the ability to model nine of the most commonly used culvert shapes. These shapes include: circular; box (rectangular); arch; pipe arch; low profile arch; high profile arch; elliptical (horizontal and vertical); semi-circular, and Con/Span culverts (see figure below). The program has the ability to model up to ten different culvert types (any change in shape, slope, roughness, or chart and scale number requires the user to enter a new culvert type) at any given culvert crossing. For a given culvert type, the number of identical barrels is limited to 25.
