Comparison of Ocean Wave Data for Dimensioning of Coastal Protection Measures in the Vietnamese Mekong Delta Region

Particularly in the Mekong Delta region, Vietnam experiences loss of land due to coastal erosion. The Vietnamese-German ViWaT (Vietnam Water Technologies) project aims at developing new coastal protection measures, which promote land reclamation especially in the western coast of the Ca Mau peninsula, where the highest waves occur during the southwest monsoon season (approximately from May to October). For dimensioning of the coastal protection measures, profound knowledge about the local ocean wave climatology including extremes is vital. To find the most reliable source of multi-year ocean wave information, various data sources are intercompared. This intercomparison is based on fields including the significant wave height, mean wave period and maximum individual wave height and includes two reanalyses, namely the ECMWF (European Centre for Medium-Range Weather Forecasts) ERA5 and NOAA (National Oceanic and Atmospheric Administration) WAVEWATCH III reanalyses, as well as data from various satellite altimetry missions, e.g., the Jason 1–3 and Sentinel-3A/3B missions. Where possible, the reanalysis and satellite data are validated with in-situ measurements, for example from field campaigns in the study region. Ultimately, the SWANOne-1D model is used to transfer waves from the grid points closest to the coast towards the shoreline to estimate the dimensioning of coastal protection measures based on extreme waves.