Stormwater Management Model (SWMM) Information for watershed water quality, hydrology and hydraulics modelers (Note this Blog is not associated with the EPA). You will find Blog Posts and Twitter Embeds on the Subjects of SWMM5, InfoSWMM, InfoSewer, ICM SWMM Networks, SWMM4 and SWMM in general.
The newer option for SWMM5 culverts uses three culvert classifications and associated equations to compute the inletcontrolled flow into a culvert using the FHWA (1985) equations. The culvert code in the culvert.c code of SWMM5 uses:
1. Two Equations for Unsubmerged culvert flow, 2. One Equation for the Transition flow, and 3. One Equation for Submerged flow.