A Golder team comprised of a geomorphologist, coastal engineers and landscape architects designed a living dyke for a client in British Columbia, Canada, supporting sustainable coastal communities by creating more dynamic structures for flood protection.
Living dykes are dune-beach systems that imitate nature and respond to changing sea levels, providing lower cost solutions to managing coastal flooding, the alternative often being to progressively increase the height of static or fixed dykes. They are designed to move and self-heal in response to high water and waves, reacting to storm events so that the crest elevation of the highest point can rise as the dune is modified by storm activity. These systems mimic natural shorelines which have a long history of changing over time to meet changes in sea level, whereas a fixed dyke will either work or fail, but cannot re-heal if it fails.
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The living dyke concept works on building defences out of materials that are mobile or can change over time (e.g., sands, gravel, and dune grasses) as opposed to being built out of rocks which are static. The footprint of a living dyke provides an ecologically suitable surface that can be colonized with flora and fauna allowing decimated ecosystems to recover and thrive because the design builds habitat as well as protection.
While there are thousands of examples of these natural systems worldwide, artificial living dykes have been successfully created to stem the impact of storm activity on the Gulf Coast of the US, enabling the preservation and restoration of sea turtle nesting grounds. Living dykes are being trialled in the Low Countries of Europe and Denmark with restoration of coastal dune-marsh ecosystems to provide flood defences. This concept had not yet been applied in the Pacific Northwest, however our design was adapted to work in the northern waters.
