Hello everyone,
I am modeling a small ditch with a culvert conveying the flow across it. The ditch runs parallel to a roadway and its north embankment is higher than its south embankment. The ditch is somewhat undersized so when the 100-yr flow is run through it some of the flow leaves the ditch by overtopping the lower south embankment before reaching the culvert. The area south of the ditch, into which the flow discharges once it leaves the ditch, is significantly lower than the ditch and it is of no interest to me. I created a 1D model of the ditch and culvert and used a lateral connection along the top of the south embankment to allow the flow to leave the system.
My question is the warning I get that the “cross section points were extended vertically for the computed water surface”. I know that you normally get this warning if your section does not extend far out enough to impound the flow that you have but since the flow I have overtopping the south bank leaves the system/ditch through the lateral structure (the elevations of the structures are taken directly from the top of the south embankment should I care about this warning ? Should I artificially raise the elevations of the south bank in the cross sections and allow the program to use the actual south bank elevations defined in the lateral structure to calculate overtopping flow?