Model road overtopping above culvert

[Yuna C]

Hi there,
I am setting up a model with a culvert and road overtopping. however the point of the road overtopping is not exactly above the culvert. As shown in the “overtopping point pic”, the low point of the road is at the road intersection.

At the moment, I put the road profile into the deck/roadway details (as shown in “hecras setting-deck and roadway” pic, but I don’t think it is the right way to model it, as it looks weird in the long plot (see in the “hecras-plan and long plot” pic)

Can I have a xs between the US and DS of the culvert ends to model the road profile?
what is the better way to model the flow through the culvert and overtopping the road?

apologise if i haven’t make myself clear. please feel free to ask clarification and thanks a lot for your help.

Thanks

Yuna

[cameron]

You could use multiple openings for the bridge and break it up into conveyance, culvert, and then conveyance sections or maybe a split reach.

I should point out that how you currently have it modeled will cause all flow going over the road to end up in the downstream channel which does not depict the actual flooding. It would appear that the flow would continue down the road by the buildings. If you care about the depths of water near the buildings, I would do a split reach or even a 2D model.

[Yuna C]

Hi Cameron,
thanks a lot for your help.
I did what you have suggested, using multiple openings. I didn’t consider split reach or 2D model as this stage as I am not really interested the flooding issue when the flow passing through the road.
here are settings and results for the multiple openings.
For me, the results look sensible, in terms of passing the flow through the culvert and road.

any more suggestions?

Thanks again.

[cameron]

With multiple openings, the split needs to be at a stagnation point. You can have the model calculate it for you if you slightly overlap the stationing of each opening type.

[Yuna C]

Got it. thanks so much again.

Yuna

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