Sea dikes removed

In the 1920s, Xiamen began expanding its area by reclaiming land from the East Sea through the building of dikes.

Back then, travel from Xiamen Island relied heavily on shipping. Sea dikes not only guarded against waves, but also enabled rail lines and highways to be built to better connect the city to outside areas and boost economic growth.

The sea dikes, including one near Yundang Port, enhanced industries such as salt fields and aquaculture. However, the dikes also created a pollution problem.

Pan Shijian, former vice chairman of the Xiamen Committee of the Chinese People's Political Consultative Conference, said: "Xiamen experiences two influxes of seawater from the Taiwan Strait, bringing clean seawater into the city. If we were to fill in the bay and turn it into land, our tidal inflow would greatly decrease, leading to a dismal future for this city.

"Despite the large cost and efforts, the Xiamen government made a resolute decision to open up the sea walls and clear millions of cubic meters of sediment, introducing seawater into bays."

Xiamen removed all the dikes that it could. Those needed for flood management and tide control were kept, and sluice gates or additional openings were added. Since 1988, Xiamen has opened seven sea dikes, including ones at Yundang Lake and Maluan Bay, the Ministry of Natural Resources said.

With the completion of sea-crossing bridges and tunnels such as the Xiamen Bridge, Haicang Bridge and Xiang'an Tunnel, the transportation functions once shouldered by the sea dikes have gradually diminished. The sea dikes had curbed Xiamen's efforts to improve the environment and achieve high-quality urban development, the ministry said.

"Returning much of the land to the sea is something you may find hard to imagine. It required a significant amount of money and it seemed unbelievable at the time," Pan said.