Offshore wind subsea risk glossary
Plain-language definitions of terms used in TIDEWATCH screens and reports.
| Term | Meaning |
|---|---|
| Scour | A hole eroded in the seabed around a structure by flow. Around offshore wind foundations it is caused by waves and currents. |
| Equilibrium scour depth | The depth at which scour stops growing under steady conditions. |
| Bed shear stress | The force of the flow on the seabed. It is larger when waves and currents act together (Soulsby 1997). |
| Shields number | A dimensionless number that says whether bed shear is strong enough to move sediment grains. Above the critical value, sand moves. |
| KC number (Keulegan–Carpenter) | Ratio of the wave orbital excursion to the foundation diameter; it controls wave-induced scour. |
| Significant wave height (Hs) | Mean height of the highest third of waves; also used as a vessel operating limit. |
| Tide level | Sea level rising and falling with the tide. |
| d50 | Median sediment grain size. Finer sand moves more easily. |
| Burial depth | Thickness of soil covering a subsea cable. Thinner cover means higher exposure risk. |
| Array and export cables | Cables linking turbines (array) and linking the farm to shore (export). |
| Jacket and monopile | Foundation types: a lattice of steel tubes, or a single large steel pile. |
| MBES | Multibeam echosounder; surveys seabed topography from a vessel. |
| ROV | Remotely operated vehicle; inspects foundations and cables up close. |
| SAR | Synthetic aperture radar; sees land and sea through cloud and at night (Sentinel-1). |
| GRD | Ground-range detected SAR product, used to detect vessels and structures. |
| Sediment plume | A muddy streak of suspended sediment trailing downstream of a structure. |
| Weather window | A period when waves and other conditions stay within operating limits so a vessel can work. |
| Scour protection | Rock armour or similar placed around a foundation to prevent scour. |
Related pages
Pilot analysis
Send us the wind farm name. We send back a first report.
Tell us the location, number of turbines and foundation type. We build the layout from satellite detection and return a first report with scour per foundation, exposure risk per cable segment and a survey priority list.