Flexible wave-dissipation network
- Saved Beishan Cliff in Kinmen County by extending the beachline and safeguarding the famous attraction from erosion by seawater
- Restored a beach at Shuangchun Seaside Recreation Area in Tainan through sand accumulation
Fong Shin has developed an environmentally-friendly, flexible wave-dissipation network, which can be used to restore eroded beaches or cliffs and move beachlines outward so waves no longer hit cliffs, reducing the risk of subsidence. The network equipment consists of injection-molded energy-dissipating components mounted on springs in a stainless steel frame, which is installed in shallow seawater.
As waves pass through the network, the seawater is diverted and de-energized, while some of the sea sand it is carrying is deposited. This helps reverse the effects of erosion on the shore by reserving the eroded silt and even pushes the beachline outward, nourishing the beach.
More cost-efficient, flexible, mobile, recyclable and environmentally friendly solution than traditional methods
Traditional methods, such as tetrapods, can temporarily ameliorate seawater erosion, but long-term use also causes ecological damage; their use has been banned in the US in the hopes of finding more environmentally-friendly solutions. Meanwhile, the riprap and offshore dyke methods are fixed, making adjustments difficult and costly.
By comparison, Fong Shin’s network equipment is eco-friendly and provides unparalleled flexibility. Once enough sand is reclaimed, it becomes sanded in the beach to prevent further erosion. Four months after installation, barnacles and oysters can cover the equipment and beach crabs can form nests, forming an ecosystem.
“The US has expressly forbidden the use of tetrapods, so we hope to promote and popularize this engineering method [Fong Shin’s wave-dissipation network] so that it is more widely adopted in the US and worldwide,” Huang said.
In addition, the network can be easily moved as a beachline is extended outward — increasing reusability — and its height can be adjusted depending on the depth of the water. Due to its relatively simple design, it is also significantly less expensive to build and set up than traditional solutions.
Safeguarded famous Beishan Cliff in Kinmen County from seawater erosion in two years
Beishan Cliff is a famous attraction in Kinmen County’s Jinning Township whose existence was threatened by the elements. Its base of sedimentary rock, which is relatively softer than metamorphic or igneous rock, was being hollowed out by tides. In addition, increasingly heavy and concentrated rainfall over the past several years had caused significant soil erosion as there is little vegetation. Both of these factors had caused the precipice to become precarious.
In September 2017, Fong Shin began deploying its network in two sets of six in the waters off Beishan as part of a two-year trial. This was accompanied by in-depth monitoring and a coastal surface topographical analysis of the site and the surrounding area.
Over the next two years, the beachline was extended seaward a total of 7 meters and the average height of the beach was increased by 10.4 centimeters. A significant amount of sandstone has accumulated under the cliff, which is no longer directly in contact with seawater, regardless of it being low or high tide. The cliff has been protected, with the biodiversity of the beach also being maintained.
Restored a beach in Tainan’s Shuangchun Seaside Recreation Area by extending beach 15 meters over three years
Tainan’s Shuangchun Seaside Recreation Area features a long beach that had for years been plagued by erosion. After appeals from the local government and residents, the Water Resources Agency’s 6th River Management Bureau in 2009 worked with Fong Shin to deploy three sets of the firm’s flexible wave-dissipating networks along the coastline near the mouth of the Bazhang River.
Over the next three years, the beach was restored to its original state. In addition, the beachline was extended seaward 15 meters from its position prior to the project.
In addition to solving the erosion problem, an accumulation of sand was achieved, restoring the beach to its original glory, Huang said.
“Our focus going forward is to use even better technology to help people — including local residents, administrative officials and even concerned academics — easily understand the situation before and after implementation of our new solution,” he said, with the aim of gaining their acceptance of the engineering method and welcoming its installation on their eroded beaches.
Fong Shin Construction
Flexible wave-dissipation network
- Flexible, mobile and reusable system to prevent soil erosion and accumulate sand
- More cost-effective than traditional prevention methods
- Environmentally-friendly solution promotes local ecosystems