Wellenbrecher

Wellenbrecher, in English breakwater, is a German term for coastal engineering structures that absorb or deflect the energy of waves before they reach the shore. The primary purpose is to protect harbors, piers, docks, and shorelines from erosion, scour, and flooding, and to create calm waters for navigation and activities.

Types and design: Breakwaters can be offshore or alongshore. Common types include rubble mound breakwaters, gravity breakwaters, and caisson breakwaters. Materials are typically concrete, large rock, or precast units; some designs use porous or rubble for energy dissipation. Submerged or low-profile structures may reduce visibility and environmental impact. The choice depends on wave climate, water depth, sediment supply, and cost.

Hydrodynamics: Breakwaters reduce incident wave energy in the protected zone but may reflect some energy and alter longshore sediment transport. Maintenance includes dredging inside basins, repairing damaged units, and monitoring for scour. Environmental considerations include shoreline habitat, sedimentation, and scour around foundations.

History: Ancient coastal defenses used masonry works, but modern breakwaters emerged in the 19th and 20th centuries with reinforced concrete and modular units, enabling longer spans and greater resilience. Wellenbrecher are widely used along the North Sea and Baltic coasts, as well as around harbors worldwide.

See also: breakwater, coastal engineering.