HecRAS 2D for large domain

[Anonymous]

Hi Chris,

Would like to build a flood model for larger region. For the same I need couple of clarifications –

1. What is limit on number of cell size in a mesh?
2. Optimum cell size (30×30/100×100) in a mesh if DEM of 10m resolution is in use.
3. Can we connect boundary condition to DSS file system as I need to include most of river network in 2D model development and it is very time consuming to add the boundary condition and their flow data multiple time?

Thanks,
Prince

[cameron]

I have done about 2 million cells in one mesh.

You usually one at least a couple points inside of each cell so 100 meter mesh might make the most sense in most areas, but add in detail where needed.

You can specify DSS files for the boundary conditions. If you are running multiple models, you would need to start with the one upstream which would then feed into the one downstream.

[Anonymous]

Thanks Cameron for your response.

For large domain we need to specify boundary condition at multiple locations to give flow hydro graph. For the same, RAS mapper do have option to add these multiple boundary condition manually and then assign flows to them in unsteady flow editor.

The whole exercise of manual addition of boundary condition and to add flow hydro-graph is very time consuming as per the domain area where flows are required at multiple locations. Do you any idea to deal such scenario of developing HecRAS 2D for large basin?

Thanks,
Prince

[Anonymous]

Our county also proposed to run a big scale floodplain inundation mapping model. It will be 1D cross section model on top of Lidar Surface; Approx. 300 cross sections on top 50 river miles lidar (surface).

Will Hec Ras able to handle such scale model?
For processing the Lidar, do you processing it in Autocad or Arcgis and export the surface to HecRas, or use some other programs?

Thanks
Hugo

[Author]

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