Flooding

Green Infrastructure and Living Shorelines

High water levels have prevailed across the Great Lakes watershed this season. While many are calling for higher outflow in order to lower lake levels, experts agree that the main issue is changing climate. (Photo: NOAA)

Flooding and Coastal Erosion in the Great Lakes


This spring, extremely high water levels and windy weather have lead to major flooding and extensive damage to coastal infrastructure in the Great Lakes. While the issue of how much we can mitigate these impacts by adjustments to the outflow of each of the Great Lakes is complicated; most experts agree that the main culprit is record level precipitation and more frequent and intense storms due to a rapidly changing global climate.

If these types of changes are expected to continue, then solving these issues will require adjustments to more than policy. One area that is receiving a great deal of attention amongst Great Lakes communities is green infrastructure.

GLC Green Infrastructure Champions Program


The Great Lakes Commission (GLC) is helping Great Lakes Communities to implement green infrastructure in their planning in order to repair the natural water cycle and therefore reduce flooding in cities. They have developed the Green Infrastructure Champions program, which coordinates a peer-to-peer mentorship program so that mid-size municipalities can work together. Mini-grants are available to those in the mentorship program. The Green Infrastructure Champions program also runs workshops to share successful green infrastructure projects and discuss green infrastructure tools. The program began as a pilot project from 2016-2018, but will continue through September 2020.

For more information visit https://www.glc.org/work/champions


An example of a green roof in Halifax, Nova Scotia. The use of vegetation on the roof reduces runoff and results in more water retention in accordance with the natural water cycle. (Photo: infosuperior.com)

Living Shorelines


Shorelines are naturally dynamic environments. Sedimentary materials tend to erode slowly from upstream to downstream so that little change is observed over a human lifetime. Unfortunately, there are many types of human activity that increase the severity and speed of shoreline erosion. For example, motorized water vehicles can exponentially increase the eroding force on a shoreline by creating waves that are stronger than what would normally be produced there. Simply getting too close to fragile shorelines like bluffs will also accelerate erosion.

Shoreline erosion at Neys Provincial Park. Trees are toppled into the river and a fence deters human traffic from accelerating shoreline erosion where no trees exist and a bluff has formed. (Photo: Infosuperior.com)

The main defense used against shoreline erosion has often been the construction of engineered hard barriers like seawalls and bulkheads. Efforts to stop shoreline erosion through the use of these structures can often become counterproductive, as they interfere with natural erosion processes. The issue here is that shorelines are meant to be dynamic, and what is eroded from one place is transported to another. Artificially limiting erosion in one location can then reduce deposits downstream, thereby accelerating erosion elsewhere.


The Lasalle Park seawall in Buffalo, New York, is an example of an engineered hard barrier. It protects the Colonel F.G. Ward Pumping Station, the main source of drinking water for the city of Buffalo. (Photo: Andi Kornaki/USACE)

In some cases an engineered hard barrier is necessary, but where there is an option, living shorelines are often your best bet. They are cheaper and result in a much more longterm solution that also benefits wildlife by maintaining natural shoreline habitats.


A living shoreline built at the Thunder Bay Marina uses native plantlife to bioengineer a marsh that mitigates erosion from wave action in a protected bay. (Photo: Infosuperior.com)

These types of shorelines work with nature, rather than against it, to ensure steady but slow erosion rather than dangerous accelerated erosion. They involve the use of native vegetation to reinforce the soil and protect against wave action. Where wave action is stronger, a combination of hard structures and living shoreline can be used.

For more information on Living shorelines, visit these websites:

fisheries.noaa.gov

dnr.wi.gov

ecologyaction.ca

livingshorelinesacademy.org


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