Where can simple wave models replace sophisticated ones in the Gulf of Riga?

We address the options for reconstructing time series of wave parameters in coastal areas with complex bathymetry and geometry by means of contemporary high-resolution multi-nested spectral wave model SWAN forced with wind information from the ERA5 reanalysis, a similar model in the Delft3D suite forced with one-point wind data, and a parametric fetch-based wave model forced with one-point wind data recorded in the neighbourhood of the locations of interest. The focus is on the Gulf of Riga and Moonsund in the West Estonian Archipelago in the eastern Baltic Sea. The SWAN model and its implementation in the Delft3D suite are applied with up to five nesting levels to explore the match between the modelled and recorded wave heights during 15 multi-month (up to two-year-long) measurement sessions at 14 locations ranging over the years 2006–2024, with a model resolution down to 11 m. The data from seven sites are presented for the first time. None of the models properly replicates wave properties at all locations. The SWAN model forced with ERA5 winds shows better performance than the simpler models at relatively open locations. The model forced with one-point wind data shows a better match with the recorded data at more nearshore locations with complex bathymetry and geometry. The simple fetch-based model forced with one-point wind data shows comparable performance at such locations. The presented results make it possible to specify the range of applicability of contemporary wave models in regions with complex geometry and provide guidance on the selection of wind information for fetch-based express models.