Storage areas in sediment models

[dpender]

Hi all,

I am trying to run a sediment simulation using storage areas to represent sections of the floodplain.

However, when I do this I get an error saying the initial storage area elvelations are not set. I know how to do this for steady and unsteady flow but how do I do this for quasi unsteady flow? Is it possible?

Cheers,

Doug

[Anonymous]

The “storage areas” in HEC-RAS are used for unsteady flow, which does not include sediment transport for those storage areas in the current release (4.1). The sediment transport algorithms used in RAS apply to channel flow only. So, I suggest that you remove the storage areas from your model and work with channel transport only. The next release of RAS (4.2) may have the ability to move sediment over lateral weirs into storage areas; but not full coupling of the unsteady flow equations with sediment transport.

[dpender]

Hi Michael,

I suspected that.

I’m not interested in fine sediment transported out of the river, rather the changes in bed elevation. It is a coarse gravel bed so there is limited sediment exchange out of bank anyway.

You can have storage areas for steady flows though. I just need a mechanism to remove out of bank flow from the channel to ensure the velocities are correct during flood events. Due to the geomtrey of the river and floodplains I cannot simply extend the sections.

Any suggestions how best to do this?

Cheers

[Author]

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