For general information, see the ADCIRC site, ADCIRC FAQ, or the ADCIRC Wikipedia page. For model documentation not yet available on the wiki, see the ADCIRC site. New content is being continuously added to the ADCIRCWiki, and material from the main ADCIRC site will be gradually transitioned over to the wiki.
The fort.90 file contains primitive weighting in continuity equation time series output at all nodes in the model grid as specified fort.15 file. This output file (fort.90) uses the output specifiers for the fort.63 file to determine its format, output frequency, etc.
See fort.90 file format for details.