Protecting the Detroit River: New shoreline design manual discusses shoreline protection options
Traditional and alternative shoreline design options explored in new manual released by ERCA.
The new Detroit River Canadian Shore Restoration Alternatives Selection Manual guides design practitioners, contractors and the public in how to design shoreline protection along the Detroit River.
The manual was created by the Essex Region Conservation Authority (ERCA), together with the Detroit River Cleanup Committee, senior levels of government and other partners. Although the manual was created for Canadian property owners and managers, much of the information is also suitable for Michigan shorelines and complements previous work released by Michigan Sea Grant, Michigan State University Extension and others.
In 1999, ERCA, Michigan Sea Grant, MSU Extension and others collaborated on a binational conference sponsored by the Greater Detroit American Heritage River Initiative. In 2000, the partners published the conference outcomes in the Best Management Practices for Soft Engineering of Shorelines. Since then, more than 30 soft engineering shoreline projects have been completed in the Detroit River watershed.
In 2011, ERCA undertook a Detroit River Shoreline Assessment, which documented existing Canadian shoreline conditions from the perspectives of both flooding and erosion, and fish and aquatic habitat. This study determined that more than 80 percent of the shoreline length has been developed as a result of urbanization, and that the shorelines fronting the large majority of the developed properties have been artificially hardened. This shoreline hardening has resulted in the direct loss and fragmentation of natural habitat along the Detroit River shoreline. The study also recommended opportunities for fish and aquatic habitat restoration and erosion protection that exist along the shoreline with the intent of strategically prioritizing future Detroit River projects.
"The term 'shoreline softening' is actually a bit peculiar – there's nothing soft about armor stone," said Tim Byrne, ERCA's director of watershed services. "What we're really doing is softening the impacts of coastal processes. When traditional shoreline protection methods like vertical sheet steel and concrete were used over the past decades, there is no way for the energy from waves and ice floes to be absorbed. What happens is that energy actually reverberates along the coast, essentially exacerbating its impact." He goes on to explain that the use of techniques, like selectively placing armor rocks below the surface, or using rocks to create an undulating shoreline, will better protect it from erosion while also providing beneficial habitat for fish.
The report also advocates retaining existing shoreline vegetation wherever possible and introducing new plantings where appropriate, citing considerable research that demonstrates the importance of riparian vegetation in freshwater environments.