The Shuangdao Bay, located at the south coast of the North Yellow Sea in the northeast part of the Shandong Peninsula, is a typical lagoon coast with its bay mouth facing north. The Bay has beautiful scenery with calm sea and well-developed shoals. A large amount of reclamation and aquaculture was carried out around the Bay in the past.
In order to implement the central government’s instruction of "Building a Blue Economic Zone on the Shandong Peninsula", Weihai Municipal Committee and Government worked out strategic plans for the implementation of the regional development and construction of the Shuangdao Bay. As one of the six key development areas of Weihai's development strategy, namely "central rise, two-axis support, circum-sea development and integrated layout", the Shuangdao Bay is defined as a modern ecological and technological town, which will lead the development of high-tech, and education and research industries, and support the development of coastal tourism and health-care industries, in order to create a town enclosing sea and a town in mountain with integration of multi-industries and town development. Based on the principles of "conforming, respecting and protecting the nature", the hydrodynamic environment and water exchange in the Shuangdao Bay should be studied to ensure long-term ecological benefits. According to the needs of the regulation scheme, it is necessary to study the regulation of the entrance sand barrier, tidal-defense criterion and beach stability. It is important to determine the elevation of revetment and depth of navigable channel to protect the intra-bay navigation and land area from being damaged by storm surge events.
Aiming at finding out the solutions of the entrance sand barrier and poor water exchange environment in the Shuangdao Bay, Prof. GAO Zhengrong in NHRI River Harbor Engineering Department has leaded his team to study a series of problems, such as water exchange, entrance rectification, artificial sand beach, tidal-defense levee elevation, pier erosion protection and so on. After over three years study, innovative solutions are presented and approved by experts.
NHRI research team conducted field investigations many times to collect historical and on-site data, and analyzed the dynamic environment and existing problems of the Shuangdao Bay scientifically and objectively.
In the Bay, tide and current are weak, with an average tidal range of only 1.66 m. According to historical data, the Shuangdao Bay was originally a lagoon of an area of about 18.5 km² in 1971, with over 10 km both in width and in depth. Since 1980s, the area of the lagoon has been reduced by nearly 80% due to reclamation and aquaculture, making the channel narrow down and tidal volume in the Bay reduce sharply. Poor water exchange has led to the rapid development of a shoal in the entrance. The study points out that sediment transported by the west-to-east longshore currents at the west side of the entrance is the main material source for the development of the entrance shoal.
The research proposes that it is necessary to increase the tidal storage area at the top of the Bay, adjust the distribution of water system and increase the overall water exchange rate effectively to speed up water exchange. Meanwhile, the research also presents the treatment solutions of the external entrance and sand barrier.
The research findings have provided important scientific basis for the planning and design of the Shuangdao Bay new science and technology town, and been applied in relevant projects implementation, producing great eco-environment benefits and social benefits.
