Nearshore wave transformation table (Dutch coast)

Practical Applications

The Wave Transformation Table can be used to obtain nearshore wave characteristics for coastal and offshore engineering and marine ecology studies. It requires sufficiently long time series (typically 20 years or longer) of offshore wave conditions to obtain reasonable wave climates in the nearshore.
  1. Sand Motor Delfland
  2. Interactive Design Tool – Holland Coast
Within the Building with Nature program, the Sand nourishment – Sand Engine Delfland, North Sea, NL is a practical example of a project in which nearshore wave characteristics were relevant to model the physical processes, while nearshore wave buoys were not yet installed. The Wave Transformation Table also proved to be useful to derive wave climates for the Coastline intervention tool – Holland Coast – ITHC. In its current state the tool is focusing on the Holland Coast, but technically the principles can be applied to coastal zones anywhere in the world.

Limitations and Lessons Learned

  • The Wave Transformation Tool proved to be a useful alternative for wave measurements to obtain elementary nearshore wave parameters. The tool can be practical when wave measurements are not available or too expensive in the area of interest.
  • Since the Wave Transformation Table depends on bathymetry, wave climates and the SWAN version used, it is recommended to update the transformation matrix whenever these factors change. This will improve the predictive capabilities of the matrix.
  • Currently, the influences of (tidal) currents and water levels on the waves are not accounted for in the model. Incorporating these effects may improve the Wave Transformation Table.
  • Since the transformation matrix is designed for average or frequently occurring wave events, it may be less suitable to predict the nearshore wave characteristics for extreme wave events.
  • Setting up a similar tool for other coastal areas in the world requires offshore wave time series of reasonable length (typically over 20 years) to obtain quality results.