Horizontal Mesh

The format of the SCHISM horizontal mesh is described in the SCHISM manual.

Users will find that SCHISM projects require refinement or extension. There are a few reasons:

SCHISM modeling is often used for
- focused analysis, requiring refinement
- sea level rise, requiring upstream extension or gridding of exposed areas.
- restoration areas.
The spatial parameterization is varied or parameterized, so there is no extensive “calibration” of a new mesh

Here we will cover:

Best practices for horizontal gridding
Attaching boundaries
Checklist for after changing the grid or boundaries.
Vertical grid.

Meshing

Meshing considerations for SCHISM

Video (Joseph Zhang, SCHISM summit)

Video (Joseph Zhang #2)

Recap/checklist

Getting to know SMS

Video (Eli Ateljevich)

Sample Data

Recap checklist

Presentation: clip_dems and efficient use of DEMS

Building the Bay-Delta mesh the standard way

Presentation: Meshing consideration for marshes and restoration

Merging/Stitching SMS mesh/maps (new work, flooded islands, etc)

Video

Recap/checklist

Vertical mesh setup

Checklist for after you change the mesh

Changing the mesh tends to have consequences in places people forget to think about, though most are straightforward or obvious. This is a checklist of gotchas that arise outside the gridding environment.

☐ Are boundaries still in the proper place?

☐ If boundaries moved, is depth enforcement preventing dry boundaries still in right place?

☐ Are flow cross sections in changed area still aligned?

☐ Are the node pairs that define hydraulic structure locations still correct?

☐ Are polygons used to define spatial inputs appopriate for new area?

☐ If grid was extended, do yaml polygons cover extended domain?

☐ Are sources excluded?

☐ Do you have submerged aquatic vegetation? Assumptions? Consider changing those file

☐ Old hotstarts not valid on new mesh, utilities will interpolate on new grid

☐ Old nudging files not valid on new mesh. Re-do.

☐ If refining/coarsening extensively on main channel, consider the effect on momentum and the algorithm.

☐ Mesh quality:

☐ Skew and area warnings in preprocessor.