Protection Strategies for Coastal Environments

“Sea level rise is like an invisible tsunami, building force while we do almost nothing.” — Benjamin H. Strauss, Ph.D., CEO Climate Central

Coastlines face a number of environmental problems, most of it due to the fact that 40% of the world’s population lives within 100km of the coast. The extraction of oil on off-shore stations, the erosion of environmentally sensitive areas, loss of dune sand, overfishing, and many other environmental issues can be listed, but one that deserves special attention is Sea-level Rise.

According to IPCC’s Assessment Report 5 (AR5), it is virtually certain that Global Mean Sea Level Rise (GMSLR), the international indicator of sea level rise, will continue growing for many centuries beyond 2100, with the amount of rise dependent on future CO2 emissions. Therefore, Sea-level Rise is not a probable issue, but rather a future reality. What is left for us, along with many actions related to the transition to a circular economy and a carbon-neutral development, is to find ways to deal with Sea-level Rise.

Coastal protection spans the interventions, structures, and measures put in place to protect coastal areas and their inhabitants against environmental catastrophic events, such as flooding and Sea-level Rise. These protections methods are mainly divided between hard strategies and soft strategies.

Hard coastal protection strategy — Seawall

Hard coastal protection strategies related to the construction of rigid or semi-rigid structures along or in front of the coastline to resist deformation from wave or current action. These structures are designed to resist extreme storm events, prevent excessive overtopping and preserve existing infrastructure. Examples of these strategies are seawalls, sea dikes, offshore breakwaters, etc. Through hard coastal protection strategies, we try to work against natural interactions in order to protect certain eras.

Soft coastal protection strategies — Dune nourishment

Soft coastal protection strategies are methods to secure and/or restore coastal line through of a body of sand. This approach focuses on restoring natural structures in order to amplify its resilience and rebuild the environment. In contrast to hard strategies, soft methods try to work with nature in order to face Sea-level Rise and other coastal problems. Some soft strategies commonly used are dune nourishment, foreshore reconstruction, and mega-nourishment.

The Delfland Sand Engine — Before and After

Netherlands has one of the most successful cases when it comes to soft strategies: The Delfland Sand Engine — A coastal maintenance strategy designed to harness the power of winds, waves and currents to help protect part of the Dutch coast, while encouraging the development of new dunes, as well as the valuable flora and fauna associated with them. This soft approach is a mega-nourishment operation that involved depositing 21.5 million m³ of sand in a single location, with the height of the deposit rising to 5 meters above the mean sea level. The wind and currents are gradually redistributing the sand along the shoreface, beach, and dunes. By using natural processes to spread the sand, this innovative approach aims to limit the disturbance of local ecosystems, while also providing new areas for nature and more leisure opportunities, at the same rate as it rebuilds the ecosystem.

Sea-level Rise is inevitable. It is a reality the current and future generations will have to face. We, as a society, play different roles in this problem. We are the main cause, the main group affected, and the main actor when it comes to developing and implementing long-lasting solutions. It is up to us to fight the problem we created.

Ph.D. candidate in environmental engineering (UFSC). Member of the WEF Global Shapers Community Sustainaiblity and Circular Economy specialist.

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