Drastic drop in channel flow

[drainage321]

This model has a large floodplain on the right of the channel. The data makes sense for the most part except I would expect the channel flow to stay the same or increase for the PK100 and PK500 runs between sections 1400 and 1245.31. Overtopping occurs after the PK50 event.

Any thoughts?

[Lonnie A]

You may need to add ineffective flow in the right overbank to keep the continuity of the flows. The conveyance capacity in the overbank increased between profiles and took some additional flow out of the channel. It really doesn’t look that bad magnitude wise. I wouldn’t consider 380 to 190 cfs of flow in the channel out of almost 3000cfs drastic. If it were going from 1000cfs to 190cfs then yes.
If you already have ineffective flow in overbank and it is overtopped this will cause this…the same if levee point overtopped. Playing around with effective flow station/elevation will fix it but in this case I doubt you’ll see a much if any difference is WSE.

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