In 2014, Australia-based Geofabrics reported on Geosynthetica about the use of geotextile containers to protect a coastal zone’s vital mangrove vegetation. As part of Geosynthetica’s extended Earth Day celebration, we look back at this article. Its details provide an exemplary case for preserving mangroves and utilizing geosynthetics in coastal protection.
MANGROVE IMPORTANCE TO MARINE ECOSYSTEMS
Coastline mangrove growth can play a vital role in the health of marine ecosystems. The disappearing mangrove growth on the Jam Jerrup coastline in Western Port Bay, Victoria has been a cause of concern for the Victorian Department of Sustainability and Environment (DSE). Geotextile containers have provided a strong solution.
Mangroves intricately entangle above-ground root systems that protect shorelines by absorbing wave energy and reducing the velocity of water passing through the root barrier. Wave energy may be reduced by 75 per cent in the wave’s passage through approximately 200 metres of mangrove, hence reducing the likelihood of coastal erosion. Mangroves are also an integral part of estuary waterways. They maintain coastal water quality by abiotic and biotic retention, removal and cycling of nutrients and pollutants, as well as promoting marine ecosystems.
In response to the disappearing mangrove growth at Jam Jerrup, the DSE investigated the use of artificial reefs to mitigate shoreline erosion and promote mangrove development. Subsequently, three separate 20m long ELCOROCK® Mega Containers were installed 100 metres off-shore to assist in accumulating sand and protect the foreshore from any high wave action.
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The decision was made by the DSE to trial the ELCOROCK® Mega Containers over the usual artificial rock wall solution due to the public amenity the ELCOROCK® solution provides over the visual impact and danger large rock wall formations can cause in a public area. The Mega Containers create calmer waters, which encourage the accretion of sediment and sand build up between the breakwater and shoreline. This enables the re-establishment of mangroves, which in the long term will protect the foreshore.
Although it is the first time this solution is being used by DSE, extensive research and modelling has been conducted to ensure the Jam Jerrup foreshore was suitable for the ELCOROCK® coastal protection alternative. Mega Container breakwater solutions have previously been successfully built in numerous locations across Australia as well as International waters.
For more information about ELCOROCK®, coastal engineering, and other geosynthetics and infrastructure sectors, visit www.geofabrics.co.