In EFDC model, often times we need to do modeling in coastal areas. In coastal areas, the flow exchange takes place between the freshwater and the salt water. So, to model coastal areas we need to use the open boundary condition. Commonly used open boundary condition types are water surface elevation (clamped boundary) and harmonic boundary conditions.
If we have measured water surface elevation, then we can use water surface elevation boundary at the open boundary. However, sometimes there are some occasions where we don’t have the data available to us. Under these cases, we can go to the ADCIRC database and then extract the harmonic constituents for the specified location.
The database for ADCIRC can be found here. I used this program / database to extract for the gulf of mexico. After you download the database for your area you will find 4 files on the downloaded folder. They are tides.in , tides_ec2001.FOR (this may be different if you have downloaded for different location), ec2001.tdb and ec2011.grd file. The file with extension (FOR) can be compiled and run to extract the data for any location.
The sample output from the ADCIRC program is as follows:
The data then extracted can be used to specify open boundary in EFDC model.
I hope this piece of information will be helpful to you. Please let me know if there is any issue using these type of extracted tidal data.