The more powerful the backwave, the faster the base will be washed away. Given this vicious cycle, both dikes made of steel reinforced concrete or "breakwaters" made up of huge concrete tetrapods dropped into the ocean off the coast are both are basically weak structures that require continual repair. Dikes must be periodically raised and new concrete tetrapods laid down.
如此惡性循環下，不管是鋼筋水泥做的防波堤，或由一塊塊三足鼎立、形似粽子的消波塊堆疊成的「離岸堤」，都是一副必須不停下藥的虛弱體質﹘﹘堤防得不時加高，消波塊不斷投下。