Category: Restoration

Part 3: Biomimicry for coastal protection

About 40% of the world’s population lives within 100 kilometers of a coast and that number continues to increase. We all know too well the challenges and hazards associated with this trend.

As described in Part 1 however, we exacerbate the coastline’s natural resilience to storm surges, high wind and waves as we continue the ‘domino effect’ of erosion and shoreline armoring. We build harbors, marinas and other public access points to the water as well as protective structures to calm the waters near those access points, but that causes adjacent downdrift shoreline erosion. That affected shoreline, in turn, then requires armoring to mitigate the wave energy directly breaking on its shoreline.

How do we break this cycle? What is the balance between human activities in and along Lake Erie and natural processes? Do human activities directly oppose natural processes or can we find a synergistic and regenerative relationship?

Much of this topic was covered in Biohabitats’ Summer Solstice 2017 issue of Leaf Litter. The theme was Restoring Ecology Along the Urban Waterfront. I encourage you to check out the issue here. I even contributed an article entitled “Ecological Restoration Toolkit for the Urban Waterfront.” Many of the current solutions that Chris Streb mentioned in his presentation at the Biomimicry Open Innovation Session were covered in that article.

I’ll touch on a few solutions today, but I encourage you to check out the included links for more information.

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Visualization of a natural, industrialized and reimagined shoreline by Biohabitats – featured in their Summer Solstice issue of Leaf Litter

 

I love the above visualization from Biohabitats. This image shows the potential of balance between the natural and industrialized coastline. Try to find all the additional green space in the reimagined photo!

The reimagined photo shows a couple of elements. One element is the floating wetland in the waterfront channel. Floating wetlands (FWs), an ecologically engineered technology, represent an effort to mimic the wetlands and marshes that existed long ago along our freshwater and marine shorelines. FWs hold the promise of returning ecological services like pollutant uptake and transformation, water quality improvement, wave attenuation, habitat, and aesthetic beautification. Biohabitats has deployed or studied floating wetlands in locations such as Jamaica Bay, NY, Potomac Yards in Washington, DC, and Orleans, MA.

Floating wetlands

Floating wetland – provided by Chris Streb, ecological engineer at Biohabitats

Floating wetlands work best in calmer waters however, generally near bays, marinas and harbors.

Higher energy environments are tougher, but wave energies are significantly reduced by underwater structures. These structures can be natural like sandbars or created elements such as living breakwaters constructed from oyster shells and spat, ECOncrete armoring units or Biohut breakwater units by Ecocean.

Oyster-ball-at-Gerritsen-Creek

Spat set on oyster ball ready to be deployed at Gerritsen Creek- originally featured in Biohabitats’ Summer Solstice issue of Leaf Litter

Another element shown in the reimagined photo above is a submerged structure attached to the seawall. This structure is related to a project I mentioned yesterday in Part 2: the “greening” of the bulkheads along the Cuyahoga River shipping channel. Biohabitats completed a project with the Cuyahoga County Planning Commission (CCPC) designing, installing and evaluating hexagonal steel casing structures attached to existing bulkheads (or seawalls) filled with various habitat-supporting materials such as bioballs, sticks and brushes. Six-month testing showed that all designs accumulated a biomass layer and small organism attachment and proved durable within the channel.

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Securing bioball baskets – originally featured in Biohabitats’ Summer Solstice issue of Leaf Litter

Green bulkheads

Successful installation of hexagonal structures along the bulkheads – provided by Chris Streb, Biohabitats

Many of these solutions use natural materials and attach to existing protection structures or exist as separate elements. If we look back at the potential areas of focus explored during the Biomimicry Open Innovation Session, one focus was materials. What if instead of natural material (woody debris and vegetation) versus built material (rock, cement and steel), we considered a third category of material? Alternative, biologically compatible materials that offer both functional and ecological benefits? What would that look like?

What if we used the principles of wave dissipation from a kelp forest or freshwater marsh or the principles of connectivity, hierarchy and material composites in a coral reef to design our coastal protection structures?

These questions and more will be the focus of my PhD research, and I will continue to share updates with you in future blog posts! Have more ideas? Comment below and I hope you enjoyed this three part introductory series!

Additional References:

http://www.un.org/esa/sustdev/natlinfo/indicators/methodology_sheets/oceans_seas_coasts/pop_coastal_areas.pdf

The featured image is a wetland restoration at Freshkills Park in New York City. More information about the restoration project can be found here:

http://www.biohabitats.com/projects/freshkills-park-north-park-wetland-restoration-design-construction/

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