1、The seawall protects the coast from erosion caused by waves and tides.
海堤防止海浪和潮汐对海岸的侵蚀。
2、The city council decided to build a new seawall to protect the beachfront properties from storm surges.
市政府决定修建一座新的海堤，以保护沿海的房产免受风暴潮的侵害。