Sea wall

A sea wall is a shore-parallel coastal defense built on or near the shoreline to stop erosion and flooding of the land behind it, typically a mass-concrete, sheet-piled, or rock-faced wall with a recurve or wave-return crest. It reflects wave energy, which can scour the beach at its toe and steepen the foreshore over time, so toe protection and a falling beach are recurring problems. Design follows the CIRIA Rock Manual and the EurOtop overtopping guidance, sizing the crest for an acceptable overtopping discharge at the design still-water level plus surge and run-up. It defends a fixed line, unlike a beach that retreats.