Waves & Tidal Data

When designing coastal defence schemes or predicting the future evolution of the coastline it is important to have an understanding of the wave climate relevant to that area as it is one of the major influences on the development of the coast.

As waves travel towards the shoreline, complex wave transformations occur as a result of the waves coming into contact with the sea bed; this results in large changes in wave height, direction, and period as waves approach the shoreline. Initially processes such as shoaling, refraction and diffraction are important. As the waves reach shallow water the transformations become more complex, due to wave breaking and bed friction.

This does not mean that we need to monitor the waves in all areas though, as computer modeling can be used to predict waves based upon a knowledge of the local area and some wave data with which to calibrate and check the model.

When we say 'some wave data' that may relate to the geographical area over which data is gathered or the time period over which it is gathered. Under the South West Regional monitoring programme a network of 10 Datawell Directional Waverider MKIII wave buoys have been deployed in 10-12m water depth.

Data is transferred to shore stations where wave statistics are calculated and transferred via the internet to the Channel Coastal Observatory for display on the web site in near real-time.

Tidal data is needed in addition to wave data to provide estimates of extreme water level conditions; this aids the determination of standards of service of flood defences. Lengthy and reliable data sets are needed to provide the information required for provision of reliable forecasting of extreme water levels and determination of mean sea-level changes. Data is also needed to provide validation and development of storm surge warning models.

Within the South West Regional Monitoring region there are 6 “A” class gauges belonging to the national network of tide gauges managed by the Proudman Oceanographic Laboratory. Rosemount WaveRadar Rex wave/tide gauges have been deployed by the Programme at

West Bay Harbour and Teignmouth Pier, providing both tidal and near shore wave data.

The data is transferred to the Channel Coastal Observatory for display on the web site in near real-time.