Adaptive measures adopted for risk reduction of coastal erosion in the People's Republic of China
Abstract Hard engineered structures such as seawalls, groynes and breakwaters are often built to reduce coastal erosion and maintain a minimum beach width for recreation along coast regions. China has a seawall coastline of some 13 830 km that is the most popular erosion countermeasure along the Chinese coast; groynes and breakwaters always appear along muddy coasts or are used as aided structures. The latter are a common way to trap sediment in a particular coastal cell to maintain the nourished beach width; reclamation has already produced 12 000 km2 of new land for the Chinese coastal area since the 1940's, including artificial islands in recent years. Soft engineering and combined structures are more and more popular in China; including those in Taiwan there are 34 documented nourishment sites. Other significant countermeasures to protect the coastline include planting Spartina alterniflora, mangrove afforestation, coral reef transplants, and introducing marine natural reserves. Since its introduction in the 1980's, over 34 km2 of coastal wetland has been covered by Spartina alterniflora in China. Mangrove afforestation and coral reef transplants have also been carried out in the south China coastal area as environmentally friendly measures for coastal management, together with the declaration of marine natural reserves. More than 8 300 km2 of coastal land has been protected in this way. Before the 1960's hard engineering works were mainly built on the Chinese coast, from then on soft engineering solutions became more common. The advantages and disadvantages of the countermeasures taken in China to combat coastal erosion are also dependent upon the country's economic circumstances. China needs to establish an effective coastal erosion management system, guiding managers and stakeholders to balance environmental and economic needs.