Inflow/Outflow Boundaries

Inflow/outflow boundaries locations specified in hgrid.gr3, usually with the preprocessor identifying the start and end of the string of nodes. The fact that a boundary is a flow or tracer boundaries is specified in bctides.in. The actual data are provided in flux.th for flow and SAL_1.th, TEM_1.th for other tracers. For info on the .th file format, you can refer to the SCHISM manual on the topic.

Where are the data?

In BayDeltaSCHISM/data we provide flux.th, salinity.th (maps to SAL_1.th) and temperature.th (maps to TEM_1.th) that go back to roughly 2008. Before that, operations were different and some of our better data sources were unavailable.

Clipping to run dates and conversion to elapsed time

The .th format uses elapsed seconds from run start for time and has no headers. Our data are provided in what we call dated format. We mix it down before the run.

What if I have to add or move a boundary?

Moving the grid relative to the boundary or a boundary relative to the grid has consequences in some far flung places. You’ll want to cover our checklist of consequences and consider which apply to your case.

Please also note that our boundary condition file is constructed, in order, from our most common boundaries. If you add a boundary you may have to inject a column into the flux.th file.

Adding Data From Other Sources (e.g. Forecasts, other models)

The port_boundary.py script in BayDeltaSCHISM/bdschism/bdschism/ contains utilities to convert or graft outputs from various data formats (other models or forecasts) onto files in SCHISM time history (.th) formats. There are a few examples of how to use this utility in the examples folder. You can find an example to take outputs from CalSim DSS, from CSV files, and from monthly CSV files <https://github.com/CADWRDeltaModeling/BayDeltaSCHISM/tree/master/examples/port_boundary/from_monthly_csv> and convert them to SCHISM inputs.