I am running a multiple opening analysis with a bridge and a culvert, and I am getting a warning that states "During the culvert inlet control computations, the program could not balance the culvert/weir flow." Does anyone know of any potential solutions to this issue? I have ineffective flow areas located in between the two openings, and my multiple opening influence area stationing is located outside of the ineffective flow area. The top of the ineffective flow area is set to the top of the existing road profile above the culvert, which is not a consistent elevation throughout the cross-section as it was obtained from field survey.
Looking at my solution in the multiple openings table, it appears that the computed headwater elevations between the culvert and bridge are close (i.e. within 0.1 ft for my profile).
My model assumes steady flow with normal depth as the downstream boundary condition.
Any sort of summary that details ways in which to resolve this warning would be very helpful.