ESTUARINE EVOLUTION AND ENGINEERING CONSTRUCTION OF THE HAINAN ISLAND

Hainan Island coast has many tidal branch estuaries,mainly grouped under 3 types,namely sand bar lagoon type,estuarine type and drowned valley type.The first type is mostly distributed in the southeastern coast,and Sanya Port is its representative.The primary coastline of the port was bedrock embayment and composed of Mesozoic granite.Estuarine valleys were filled with the weathered granite sand and mud to become land and gradually turned into sea built plain with sand bars and lagoons scattering in.The second one is mainly distributed in the west of the island,rising from estuaries within tectonic fault zones.Its significant formation is due to deposits from river and coast erosion into the estuaries and tidal dynamics coming from great tide holding capacity as well.And the third one is mainly found along the north and northeast coast sections of the island,but such type is now in its late evolution and going near to the end of their lives.