Geosynthetics for flood protection structures

21st Sep 2020
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Geosynthetics For Flood Protection Structures

Geosynthetics can be used for a wide range of applications. As alternative solution for permanent or temporary coastal structures. To offer erosion protection during island reclamation. For flood protection structures, just to name a few.

Today’s world is faced with many serious threats. Climate change and sea level rise are amongst those. Numerous challenges lie ahead of us in the quest to safeguard islands, cities and countries from rising seas. It is important to find ways to adapt to higher sea levels, higher levels of natural stress on coral reefs, higher temperatures, higher frequency of severe storms and varying rainfall patterns.

Maldives Eminent Threat

The Maldives – an archipelago of 26 low-lying coral atolls located in the Indian Ocean – is amongst the most vulnerable. The islands of the Maldives are a mere 1.5m above Mean Sea Level (MSL), which makes them highly vulnerable to flooding.

The small size of the islands and their low elevation makes the Maldives one of the most vulnerable countries to the predicted climate change and impacts such as sea level rise, extreme weather events and storm surges. Strengthening coastal zone management and improving coastal protection of the islands are priorities. (Dr. Ahmed Shaig, Co-Author of National Adaptation Program of Action (NAPA), Author of Survey of Climate Change Adaptation Measures in Maldives)

Erosion started being a significant issue in the islands as early as the 1980s. In most resort islands, erosion has been identified as an issue since the resorts opened. To put it in percentages, more than 64% of inhabited islands and 45% of tourist resorts have reported ‘severe’ erosion.

Maldives Adaptation Strategies & Measures

There are four broad planning strategies commonly prescribed for adaptation to climate change and sea level rise in coastal states: i) do nothing; ii) accommodate; iii) defend or; iv) retreat. Amongst these, the only viable options for small island states are mainly to defend and to some extend accommodate. The adaptation measures found in the islands broadly belong to these two categories.

The most popular engineering measures in the islands to overcome the challenges are seawalls, breakwaters and groynes. A number of materials are used, including innovative materials such as sand filled bags made of geo-textile material or geo-bags, which offer a more aesthetically pleasing structure, and submerged geo-textile tubes. The main challenges to promoting these types of soft adaptation measures are the lack of awareness and perceptions of ineffectiveness. The key opportunities are the low cost, familiarity and benefits over the longer timeframe. (Dr. Ahmed Shaig)

For decades, geosynthetics have been utilized to mitigate the impact of storms on shorelines and to guard against future sea level rise. Watch how we designed a low-crested breakwater from sand-filled geosynthetic containers to protect an island’s beach and pool. The design consisted of over 80 containers, each 25m long and weighing in excess of 300 tonnes. The full case study is available here.

Filip Stefanovic

If you would like to know more about geosynthetic containers, Filip Stevanovic, our in-house GSC expert and head of engineering, is ready to guide you through a webinar. He can be reached at [email protected] or +971 4 885 3944.