By KIMBERLY HIRAI
Capital News Service
LANSING — The Detroit River shoreline has miles of steel sheet pilings, concrete break walls and cement used to deepen the river and increase water flow for safety, navigation and industry.
Credit: Department of Natural Resources and Environment
Freighters needed such “hard” shoreline engineering to load and unload coal, salt, cement products and other materials, said civil engineer Patrick Doher of the Ann Arbor office of JJR, a landscape architecture firm. Manufacturers along the river processed those raw materials and shipped the final product the same way.
That hard edge is no longer needed to move freight in parts of the Detroit River. And its legacy isn’t great for river species looking for a place to live, for the expense of repairing its crumbling or cracking rim, and for the eyes of Detroiters and visitors.
Rising in its place is the concept of “soft” shoreline engineering like that designed and engineered by JJR along Gabriel Richard Park’s river edge and in sections of William G. Milliken State Park and Harbor in the waterfront’s East District.
Construction of a section of Milliken, Michigan’s first urban state park, was plagued by “concrete dinosaurs,” when the project began in 2008, said Luba Sitar, the Department of Natural Resources recreation division manager for southeastern Michigan.
Concrete and steel had transformed 31 of 32 miles of river shore into commerce and industry’s backdoor, according to a report by John Hartig, manager of the U.S. Fish and Wildlife Service’s Detroit River International Refuge, and Anna Cook, a biological technician at the agency.
Part of Milliken was transformed into a stormwater-treating wetland. Staff removed industrial relics— boat launches, wooden structures, train tracks and the turnstile on which train cars turned after dropping their loads, Sitar said.
Here’s how soft shoreline engineering works: Instead of concrete and steel, designers put vegetation, stone and other materials that soften the edge while maintaining a stable shoreline.
The technique uses ecological principles to reduce erosion, keep the shoreline intact, restore habitat and improve public access. A soft shoreline also creates a visually appealing “waterfront porch” for businesses, industry, homeowners and public places and can increase waterfront property values.
Hartig said most projects so far have been in Southeast Michigan, including one proposed for the St. Clair River. However, the techniques have been used elsewhere in the state, including Gull Lake near Kalamazoo and along northern Michigan streams.
A Detroit American Heritage River Initiative conference in 1999 led to a manual of best practices that guided testing and demonstrations of the technique along the Detroit River and western Lake Erie. Since then, the state and U.S. Army Corps of Engineers have approved 38 projects costing more than $16.5 million,
JJR’s Doher said natural stone and plants replaced the East District’s hard industrial shoreline, creating habitat for fish and wildlife native to the Detroit River.
Because freighters don’t unload in the East District anymore, “we were able to reduce that hardened and sheeted edge and create more natural habitat,” he said.
Construction was completed in 2009 in a complicated process.
Sitar said an orange snow fence marked where old and new soil met. The team brought in clay to the 5-acre site to create islands lined with burlap-wrapped logs and topped with wetland plants. The roots will eventually stabilize the shoreline as the logs disintegrate.
The soft shoreline also cleans stormwater before it flows into the river. Stormwater now enters the wetland area from 11 acres in and near Milliken State Park before spilling into the Detroit River.
Sitar said she hopes local school science classes will monitor progress by taking water samples at the top of the wetland and at the discharge site.
At its best — and depending on a project’s needs and materials — soft shoreline engineering costs half as much as hard shoreline techniques, where concrete or steel sheet pilings cost about $2,000 per linear foot, according to the refuge’s Hartig.
While hard design structures often have a limited life, soft engineering produces living shorelines that can repair themselves.
The technique can’t be used everywhere, but where appropriate, the option offers multiple benefits, Hartig said.
“It’s an initiative or practice whose time has come,” he said, adding, “You’ve got to be sort of opportunistic. You’ve got to be at the table at the right time for this.”
Kimberly Hirai writes for Great Lakes Echo.
© 2011, Capital News Service, Michigan State University School of Journalism. Not to be reproduced without permission.