Michels, Luedtke Perform Integral Work in Cat Island Restoration
The Cat Island restoration project in Green Bay began restoring a chain of islands in the lower bay in 2013. Dike structures created three cells, which over the next 20 years, will be filled with dredged material from the navigation channel
Two Midwestern dredging companies played a significant role in a long-term island building project that promises environmental and ecological benefits to Green Bay in northeastern Wisconsin, and also increases the region’s capacity for the placement of dredged materials. In April 2017, Luedtke Engineering of Frankfort, Michigan, completed a maintenance dredging project, which added 410,000 cubic yards to the islands.
Michels Corp. of Brownsville, Wisconsin, and, Luedtke performed the original work on the Cat Island chain, three islands being rebuilt nearly 50 years after the original islands were washed away by high water levels, waves and ice.
Over the next 20 years, the islands will take shape as dredged materials from the Green Bay navigation channel are deposited into three cells constructed by Michels Corp. The new islands will recreate ecologically vital wetlands for the benefit of fish, wildlife and natural vegetation. The wave barrier portion will help protect the shoreline from erosion.
Michels Corp. constructed a 4.3-mile long, spine-like structure with six protruding “legs” that form three cells into which dredged materials will be deposited. The dike ranges from 4 to 8 feet high. Michels also designed and constructed a 350-foot-long mooring facility, driving the 50-foot-long metal sheets 42 feet into the lakebed.
In all, Michels Corp. placed 300,000 tons of armor stone and 800,000 tons of core stone (crushed limestone), completing the project in December 2013 – 1.5 years ahead of schedule, according to Paul Wiedmeyer, Michels Foundation’s senior project manager.
Michels used a Caterpillar 345C hydraulic excavator to place the armor stone. A Manitowoc 10000A-1 crane and ABI TM18/22 Mobilram driller placed the sheeting sections. John Deere bulldozers and Caterpillar rollers were also used to smooth and compact the core stone and gravel atop the dyke. As many as 50 trucks a day delivered stone during the construction project, Wiedmeyer said.
A road along the top of the dyke enables trucks to travel to and from the mooring facility and deposit dredged material for vessels that mechanically unload. Vessels may also hydraulically unload into the cells.
“It was a highly successful project because of Michels’ ability to self-perform every aspect of work, to develop an innovative construction plan using GPS enabled equipment, and because of the dedication of the crew who worked throughout the winter to keep the project well ahead of schedule,” Wiedmeyer said.
The $15 million final cost was about $7 million less than had been projected several months earlier. The U.S. Army Corps of Engineers Detroit District was the main project sponsor, joined by Brown County, Wisconsin, the U.S. Fish and Wildlife Service and U.S. Environmental Protection Agency.
In August 2016, the Corps awarded Luedtke Engineering the Green Bay Harbor maintenance dredging contract, for $3.61 million, to dredge approximately 410,000 cubic yards. Dredging was performed in the outer bay channel to a 26-foot depth for navigation, with placement of all dredged material into the west cell at Cat Island. Luedtke removed the existing vegetation on Cat Island prior to placement activities.
Luedtke used its dredge Derrickboat #10 (built in 1946) with a Manitowoc 4000W crane, and its dredge Derrickboat #12 (1953) with a Liebherr HS883HD crane. Both dredges are 130 feet long and 40 feet wide. Both used an eight cubic-yard cable arm clamshell.
Luedtke’s 1,600-horsepower, 72-foot tug Kurt R. Luedtke (1956) shuttled four scows to a 16-inch hydraulic unloader, Lucille T (1966), which is 80 feet long, 30 feet wide. The Lucille T hydraulically unloaded the scows and placed the dredged material into the west cell. Two of the scows each had an 1,800 cubic-yard capacity; the other two each had a 1,000 cubic-yard capacity.
Company President Kurt Luedtke said his firm had dredged 390,000 cubic yards by Dec. 8, 2016, but high winds and ice forced a halt to dredging activities. Dredging resumed on March 20 and wrapped up by April 1.
Major commodities transported through Green Bay Harbor include coal, limestone, cement, salt, pig iron, fuel oil, liquid asphalt, lumber, gypsum, petroleum products, heavy equipment and general cargo, including overseas cargo, according to the Corps.Edit Module