Ecocoast carried out a coastal protection project recently on Saadiyat Island in Abu Dhabi using geosynthetic containers to prevent erosion damage.
During construction works, the project team found that the original land level needed to be raised to ensure a safe foundation for the luxury villas and other facilities being built on the island.
However, while this process was being carried out, the team found that the reclaimed land faced the threat of erosion during high tides and extreme weather conditions, leaving the slope unprotected and exposed to strong waves.
Therefore, the client called on Ecocoast to resolve the problem, requesting a temporary, preventive solution that would stop further erosion and protect the villas.
The Challenge
Prior to proposing a solution, the Ecocoast team carried out an extensive survey of the location and found that installation would be a challenge as conditions constantly shifted from wet to dry, based on water levels.
Furthermore, the team needed to incorporate the existing structure into its design of the revetment and therefore collaborated with an external consultant to verify the structural stability of the revetment. However, Ecocoast was ultimately responsible for the design, supply and supervision of the project.
The team decided that the ideal solution for the temporary revetment was to use geosynthetic tubes for its construction, while also keeping in mind that the tubes needed to be robust enough to withstand the constantly shifting conditions, as well as exposure to direct sunlight – particularly in high-temperature months.
An engineered approach
Geosynthetic containers are three-dimensional systems, manufactured from geotextile materials filled with sand. They require an engineered approach. GSCs are regarded as innovative, economic and environmentally friendly systems. They have the added benefit of enhancing marine habitats.
The containers come in varying sizes. The weight provides stability and projects have been designed and constructed in high wave energy coastal areas with waves over 12 meters.
Moreover, for the Saadiyat Island project, the tubes were installed on a layer of geotextile, so as to provide an extra element of protection against erosion by preventing the free flow of water.
The revetment was designed to withstand a variety of weather conditions, with a return period of 10-years. Some of the key design criteria checked included global stability and wave overtopping. This was to ensure that the revetment performed as designed under all environmental conditions.
During the installation process, the tubes were put in place during wet conditions, with the first layer of tubes and scour protection installed in a trench that was lined with geotextile.
Once in place, the trench was then backfilled and compacted, in order to install the second layer. This process was repeated until the revetment was complete.