Seawall - Definition and Overview

A seawall is a form of hard coastal defense that are constructed on the inland part of a coast to reduce the effects of strong waves, typically to defend the coast around a town or harbour from erosion. The walls can be sloping, vertical or curved to reflect wave power. The term is typically used to describe walls built on the land parallel to the coast, but may also apply to breakwaters and groynes which are built in the water.

Seawalls are effective defenses over the course of many years, but may cause erosion in the long run. They cause the energy of the backwash to be reflected to the beach material beneath and in front of them, so the beach materials is gradually eroded. This problem may be reduced if coupled with beach nourishment (replacement of the eroded material) or rock aprons which reduce wave power by percolating the water slowly through gaps.

Seawalls may be constructed from a variety of materials, commonly reinforced concrete, boulders, steel or wire cages filled with pebbles. Seawalls require constant maintenance as the waves will constantly attack the base of the walls and cause them to be weakened. Modern concrete sea walls tend to be curved to deflect the wave energy back out to sea, reducing the force

See also

• Retaining wall