Twin Dyke – Building with Nature for Multiple Benefits

The obvious solution to a sea defense problem is usually the easiest one to accept, because it’s indeed so obvious.

Image source: Noorderzijlvest Water Authority

If a sea dyke is not strong enough for the consequences of future climate change, then it should be reinforced to meet the new requirements.

However, beside an estuary on the southern shoreline of the Wadden Sea, the regional water authority and the provincial government proposed a daring, innovative solution that costs less, is nature-friendly, and potentially brings many additional benefits to the area.

Completed in early 2020, the Twin Dyke is a test bed for a Nature Based approach to coastal flood protection.

Higher, wider, stronger

Much of the Dutch coastline is protected by dykes that were constructed long before anyone had ever heard of Climate Change, and a massive program of works is now underway to upgrade the country’s flood defenses.

During the past five years, Regional Water Authority (RWA) Noorderzijlvest has reinforced 12 km of sea dyke between Delfzijl and Eemshaven beside the Wadden Sea, on the north-eastern coast of the Province of Groningen.

In this project the existing sea dyke had to be raised, widened, and strengthened to withstand wave action resulting from higher sea levels and storm surges.

But over one section of the dyke, in cooperation with the province of Groningen, the RWA took a totally different approach.

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