When defining the roadway data for the culvert, the following parameters are required:
- Roadway Profile
- Roadway Station
- Crest Length
- Crest Elevation
- Roadway Surface
- Top Width
The roadway elevation can be either a constant or vary with station. An initial roadway station may be defined or left at the default of 0.0. The stationing is used to position culverts along the length of the roadway profile when choosing the Front View option.
The roadway surface may be paved or gravel or an overtopping discharge coefficient in the weir equation may be entered. As the overtopping flow will cross the roadway surface, median, and shoulders, this discharge coefficient should take all of these materials into account. Select a paved roadway surface or a gravel roadway surface from which the program uses a default weir coefficient value. If input discharge coefficient is selected, enter a discharge coefficient between 2.5 and 3.095.
The values entered for the crest length and top width of the roadway have no effect on the hydraulic computations unless overtopping occurs.