For a long time, the WCB has only built wall-type dikes which stand perpendicular to the surface. In the past the main purpose of the sea dikes was to prevent intense waves brought by bad weather from heading inland. Today the coast suffers from the effects of inland gravel extraction and ground water extraction and is continually eroding.
過去築海堤是為了防堵惡劣天候帶來的暴潮與海水倒灌，危及海岸住家；如今海岸受內陸抽沙、地層下陷等影響，不斷侵蝕，無人落腳的海岸，也競相築起海堤。