RAS Mapper Normal Depth Boundary Condition

[madelineh]

Hi all,

I have a 2D HEC-RAS (v 5.0.7) model with a normal depth boundary condition at the downstream end of the grid. The “compute separate water surface elevation per face along the BC line” option is selected. When I right-click on the boundary condition using RAS Mapper, the time series plot of water surface elevation is constant throughout the simulation, even though flow is not constant. However, when I click on the individual cells, the water surface elevation varies throughout the simulation, as expected.

Has anyone else noticed this issue? I am wondering if this is an issue with the model, or a just bug in the RAS Mapper.

Thanks!
Madeline

[Luis Partida]

In my experience I have only utilized the “compute separate WSEL per face along the BC line” to determine if I needed to break up my BC line in to multiple based on face elevation variances. The final output is an averaged WSEL along the cell faces if I am not mistaken. So if I had a full 2D model where I believe there was potential for WSEL variances, I would select the “compute WSEL per face…” and run the model, check some of the cells and either break up the BC line into a couple different locations and turn that option off or was satisfied with a single BC line and turned it off and re ran(simplify calculations)

[madelineh]

Thank you for your insight. I will try breaking the BC line based on the elevation variances, as you suggested.

Have you tried clicking on the BC line is RAS Mapper to plot WSE vs. time? I have tried doing so with a number of models, and they all indicate WSE is constant in time. This can’t be possible as there is no flow at the beginning of the simulation. I’m wondering if this is just an issue with the RAS Mapper.

[Luis Partida]

It is best to get that output from the geometry data editor. You can click on the BC line and select “Plot stage and Hydrographs” you will get the same information

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