The hydraulic structures module is a facility to represent structures such as tidal radial gates, weirs and culverts with the model using common representations from 1D hydraulic modeling. Fairly complete documentation may be found in the Hydraulic Structures in SCHISM.
Besides this manual, there are two things you might want to explore:
- California Dept. Water Resources (DWR preprocessor includes structures and uses geophysical coordinates rather than node numbers in its interface. This may be a convenient if you regularly update grids.
- The Submerged Aquatic Vegetation module reduces to fairly straightforward drag formula for the case of emergent vegetation. If you have something like bridge piers that you want to represent using the usual A*C_d*|U|*U approximation, you might want to use the vegetation module.