HOW GEOSYNTHETICS CAN HELP MITIGATE THE RISKS OF SOIL EROSION AND IMPROVE COASTAL PROTECTION
Over the last few years, there has been a noticeable shift in weather patterns around the world, with violent storms becoming increasingly frequent. Coupled with the risk of rising sea levels and soil erosion, especially on sand-based islands, the need for coastal protection is fast approaching the ‘must-have’ status for projects on or near the sea.
This is where geosynthetic containers come in – billed as an alternative solution for coastal protection or temporary marine structures, they are manufactured from geotextile materials and filled with sand to create durable and long-lasting barriers against rough marine environments and inclement weather.
Geosynthetic containers (or GSCs; or geotextile tubes and bags; or geotubes and geobags) are three-dimensional systems that provide stable and effective coastal protection while still being low impact, both environmentally and visually. These systems are not sandbags or bulker bags, as is commonly misunderstood – they require a precision-engineered approach for installation and come in a variety of sizes, ranging from 100 kilograms up to in excess of 600 tonnes. This weight provides stability and allows for projects to be designed and constructed in high wave energy coastal areas, where waves can reach more than 12 metres in height.
Some of the applications for geotubes
These are commonly found when constructing artificial islands, where the geotubes are used to ensure there is no erosion beyond a certain point on the beach. The revetments are buried in the sand and are not visible above the ground.
Groynes or the core of breakwaters:
In this application, the geotubes form the core of the structure. Once filled with sand and installed in place, they are covered with a layer of geotextile and rocks of varying sizes.
Geotubes installed on the seabed form a key part of coastal protection plans. They dissipate and break up wave energy, while improving the stability and longevity of the coast due to the lower wave energy. Furthermore, an added benefit is that these geotextile structures encourage the growth and diversity of a variety of marine life, particularly soft corals and kelp, thus benefiting the local marine ecosystem considerably.
These are structures found at the end of a perched beach, where they help stop the erosion of sand. They create a stabilised beach without creating a visual impact or posing a safety risk as they are soft structures. They also eliminate the need for a rock breakwater.
Our in-house engineered Ecotubes have been used on several projects across the MEA region, including on hospitality projects such as the Hilton Abu Dhabi, Sheraton Dubai, and the Fairmont Ajman in the United Arab Emirates. We deploy our Ecotubes using a proprietary stability calculation tool, which allows clients to create graphs from their own data, allowing for the creation of different scenarios to assess waves, container size and stability, in order to provide a ballpark estimation for the project.
Geosynthetic container versus rock structures
The use of geosynthetic containers has proven to be a more cost-effective alternative on projects where rocks are not readily available. On such projects, the transportation of rocks from quarries via trucks or barges drastically increases costs. However, with our geosynthetic containers, and the ease of availability of local sand, we can ensure that costs, time wasted, logistics and all other associated expenses are kept to a minimum.
In addition, since the size and dimensions of GSCs are easily customisable, they offer greater flexibility compared to rock-based structures. This also has several environmental benefits as the footprint of GSC structures are often smaller than rock-based ones and cause less disruption to delicate marine ecosystems. Once the purpose of the structures has been fulfilled, the sand used to fill them can also be repurposed, thus reducing material wastage. Our geotextiles are also biodegradable, making them the eco-friendly option.
New proprietary GSC software
Last but not least, an additional benefit of using Ecocoast’s engineered Ecobags and Ecotubes is the new calculator that we have developed – Geoforce. This calculator’s basic function is to verify whether a certain type of geobag or geotube can withstand the environmental conditions of the installation site.
It can be used to confirm the stability of different structures made from GSCs such as groynes, revetments, breakwaters, causeways etc. The calculator is highly customisable and can incorporate GSCs of any size made from both woven and nonwoven geotextiles. Depending on the input parameters, the calculator generates results to verify whether the defined structure is stable under the wave and current condition provided.
In fact, we’ve been able to test products within the Ecocoast product range or test products that are customised as per the client’s requirements. The calculator can also add a layer of armour rocks on top of the GSC structure and run calculations to identify the nominal diameter of the rocks to be used in the area.