Is there a way to implement flow roughness factors or seasonal roughness factors in 2D mesh?

[Anonymous]

Hi there,

Perhaps there is a way I didn’t figure out…

Is there a way to add flow roughness factors or seasonal roughness factors to a 2D flow area?

Or some way of varying the manning roughness map during the unsteady simulation?

[Anonymous]

By implementing a shapefile to be utilized as a varying mannings value, you are doing what you are questioning.

You can also override that using the mannings override tool.

But there is no current way to alter mannings values by depth.

[Zain]

any update on this topic since 2019?

[A Atkinson]

Hi Zain –

I don’t believe there has been any updates on this topic since 2019; that is, there isn’t a way to change Manning’s n values as the simulation is running.

I suppose a work around would be to break up your simulation into smaller time frames and use a different land cover file or Manning’s n values for each of the smaller simulations. So, for example, if you had a simulation you need to run from June to December, you could break it into a June – October simulation and an October – December simulation. For the June-October simulation you could use a geometry file that had Manning’s n values associated with the summer, and for the October – December simulation you could use a geometry file that had Manning’s n values associated with the fall/winter.

Also, I know you can assign a Manning’s n value to Open Water, but I’m not sure if simulated flow gets that n value or if that value is only assigned to areas where Land Cover = Open Water.

– A

[Author]

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