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.
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 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.
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.
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!
The featured image is a wetland restoration at Freshkills Park in New York City. More information about the restoration project can be found here:
Back in late February near the start of my PhD, my sponsors were asked if they had an interest in organizing a Biomimicry Open Innovation Session for 2017. Similar to last October’s Open Innovation Session organized by former Biomimicry Fellow Emily Kennedy (now a graduate!) and her sponsor GOJO, the idea is to pose a challenge statement unique to your industry that is open to collaboration and biomimicry design thinking to seek potential solutions. These sessions leverage the regional biomimicry community with support from Great Lakes Biomimicry.
Following many planning sessions with my three sponsors (Biohabitats, Cleveland Water Alliance, ODNR) as well as Great Lakes Biomimicry throughout the year, the Innovation Session was held at the Great Lakes Brewing Company Tasting Room on Wednesday November 1st from 1-5pm. 26 people from 8 unique institutions participated with 10+ biomimicry models identified and abstractions generated!
The challenge statement was as follows: To incorporate habitat features into existing and/or new shore protection structures to provide aquatic habitat for targeted fish species and enhance ecological functions, benefits and services in both freshwater riverine and coastal environments
Three potential focus areas were given:
- Structure: Alter structure to absorb or dissipate instead of reflect or refract wave energy. Wave reflection & refraction result in altered sediment transport pathways along Lake Erie’s shoreline.
- Habitat utilization: Nursery habitat for larval and young fish, habitat refugia that provide hiding places and protection against predators, feeding habitat for foraging fish.
- Materials: Soft structures utilize natural materials, like woody debris and vegetation, while hard structures are comprised of rock, cement and steel. Consider alternative, biologically compatible materials that offer functional benefits. Or, offer a solution between hard and soft structures or a structure that can be a combination of both hard and soft materials.
Throughout this week, I have prepared a three-part series (Tuesday through Friday morning) to share the content from the introductory presentations given at the start of the Innovation Session. I am presenting all this information for a few reasons. First, for those who didn’t attend to learn about what was presented and discussed. Second, for all those who follow this blog to learn more about the background behind my PhD thesis. 2018 (Year 2) is coming up for me already, which means a hopeful thesis proposal defense by the end of Year 2!
The three presentations were:
- Characterization of the Ohio Lake Erie shoreline through the lens of coastal protection – Jim Park, ODNR Coastal Engineer (Part 1)
- Aquatic habitat for targeted nearshore and open fish populations of Lake Erie – Scott Winkler, Ohio EPA Division of Surface Waters (Part 2)
- Coastal restoration: Project examples of coastal protection and ecological function – Chris Streb, Biohabitats Ecological Engineer (Part 3)
Part 1: Characterization of the Ohio Lake Erie shoreline through the lens of coastal protection
What is a shore protection structure?
Jim gave many examples, which included revetments, seawalls, groins, breakwaters and beach.
Revetments are typically composed of large, rough, angular rock on a slope that dissipates wave energy on both the slope and rough surface. Revetments typically protect the foot of a cliff or a dune, or a dike or seawall against erosion by wave actions, storm surge and currents.
Seawalls are vertical structures at the land/water interface designed to prevent erosion and storm surge flooding. They are made of concrete block, cast-in-place concrete or steel sheet pile. Seawalls reflect wave energy; they do not dissipate. Seawalls provide easy access to the water by boats docked along the wall. Steel sheet pile seawalls are almost exclusively used along the mouth of the Cuyahoga River in downtown Cleveland for transportation of goods by freighters and for recreational boaters to dock by restaurants along the water.
Groins are shore-perpendicular structures made of stone, concrete or sheet-pile. They are effective in beach protection and had widespread past use in Ohio. If you are familiar with the Cleveland coastline, there are a few stone groins at Edgewater Beach and a few being installed at Perkins Beach currently!
Breakwaters can be submerged, off-shore or connected to the land and are made up of large stone. They are designed to reduce wave action. Breakwaters are usually built to provide calm waters for harbors and marinas. Submerged breakwaters are specifically built to reduce beach erosion. A beach is typically formed or retained on the landward site. They may also be referred to as artificial “reefs.”
If beaches are there, they are the most natural and effective form of shore protection.
The Ohio shoreline of Lake Erie is one of the most developed and structurally protected of the Great Lakes. Structural protection began in the early 1800s with the development of harbors, but any protection structure caused adjacent downdrift shoreline erosion. The affected shoreline, in turn, then requires armoring to mitigate the wave energy breaking directly on the shoreline rather than dissipating along the beach. As the Lake Erie Commission explains in their 2004 State of the Lake Report, “This ‘domino effect’ of erosion and shoreline armoring continues to this day.”
These shore protection structures have limited natural habitat value and alter coastal and hydrologic connections that in turn affect ecological processes and biological life cycles. On the mainland shore of western Lake Erie, the current coastal protection structures are not favorable to the nearshore biological community in both structure type and composition.
We know that coastal protection structures alter the primary mode of wave energy reduction; i.e. some reflect the waves back into the lake or refract the waves instead of dissipate. We also know these structures disrupt sediment (or the more technical term – littoral) transport pathways across the lake and many cause downdrift shoreline erosion. We also know they disconnect the land-water interface. How does this connection and other disruptions affect ecological processes and biological life cycles? We will touch on this question some with Scott Winkler’s presentation on nearshore fish populations tomorrow for Part 2!
Feel free to comment below or reach out to me on LinkedIn throughout this week if you have questions or ideas to contribute!
Fuller, J.A., and B.E. Gerke. 2005. Distribution of shore protection structures and their erosion effectiveness and biological compatibility. Ohio Department of Natural Resources, Sandusky, Ohio.
[LEC] Lake Erie Commission. 2004a. State of Ohio, State of the Lake Report. Toledo, Ohio.
*Note- All shore protection structure photos were part of the presentation given by Jim Park on November 1st at Great Lakes Brewing Company Tasting Room. Permission was granted to share content and photos.