Beach Nourishment, Qijin Windmill Park, Kaohsiung, Taiwan

In the past, the beach area along Qijin Coast in Kaohsiung has been reduced yearly because of wave erosion. In addition, the expansion of Kaohsiung Harbor, the construction of the South Star Project, the development of the Intercontinental Container Terminal, and other related factors caused the replenishment of coastal sand sources to be reduced, resulting in increased coastal erosion. The investigations showed that the coastline has receded by nearly 100m in the past decade.

In 2011, the authority constructed an offshore submerged breakwater with precast concrete armor blocks to reduce the wave and velocity. In addition, sand was pumped from the sea to replenish the severely lost Qijin beach through artificial beach nourishment, but the effect was worse than expected. Although the erosion of the shoreline has been slowed down, the beach was not fully restored successfully.

Based on multi-scheme evaluations, the designer applied ACETube^® parallel to the existing submerged breakwater to improve its original design function of restoring the beach. Such an arrangement developed a cofferdam-like area, preferably as a sand trap to store the sand pumped from the sea. After the completion of the filling, the ACETube^® and the sand trap zone thus can effectively prevent and protect the coastal seabed scouring. The direction of coast drifting sand from south to north also has favored the beach nourishment completed effectively in a short period.

The actual amount of hydraulic sand backfill in this project was 13,600 m³. The monitoring result of the backfilled area has indicated that, after two months of the completion, no loss of sand was observed at the site. ACETube^® also has been almost covered by sand. In addition, approximately 17,500 m³ of sand has been recovered from the beach outside the ACETube^®, showing remarkable results for beach nourishment.

Coastal erosion and coastline retreat have caused an increasingly severe land loss problem. Because of the need for national constructions to follow the world trend, the planning and design of coastal protection projects must satisfy the function of national security and meet the multi-functional objectives of environmental protection, ecology, and aesthetic landscape. Traditional protection methods for construction have been unable to improve and meet the above requirements. Only innovative techniques and materials with green thinking can complete the project construction objectives of energy saving, carbon reduction, and sustainable development.

ACETube^® can be successfully applied for coastal revetment, tidal inlet restoration, and artificial beach nourishment. Because of the situations in which the traditional coastal protection method cannot correctly achieve the purpose of protection, the application of ACETube^® can successfully improve the objective that the original design cannot reach. In addition, the use of ACETube^® only acquires in-situ materials and eliminates the need for reinforced concrete structure. Its construction has reduced the impact on the overall ecological environment and natural landscape to the greatest extent possible. It fully meets the objectives of net zero emission of energy saving, carbon reduction, and sustainable development required by national constructions in recent years. It is worthy of further promotion and application.