Best Project Water/Environment: Cat Islands Chain Reconstruction
Construction of more than four miles of wave barrier and access road on the Green Bay lake bed served larger efforts by the U.S. Army Corps of Engineers to restore Cat Islands, a small chain that functioned much like coastal barrier islands, protecting shallow bays and wetlands, before being washed away in the 1970s.
Completed in 18 months, the 4-ft-high to 8-ft-high dike includes armor stone sides and a 12-ft-wide graveled road. A series of 24-in.-dia and 84-in.-dia concrete culverts are designed to contend with surges caused by fluctuating water levels. They also will promote circulation among islands made of 270 acres of material dredged from the bay.
Before completing work, crews trucked more than 750,000 tons of core and armor stone during more than 37,000 round trips between quarries and the project site, logging 2 million miles in all. Establishing two-way traffic facilitated quicker material delivery and allowed for direct placement of stone upon arrival from the quarry, eliminating the need to stockpile.
The approach also eliminated redundant QA/QC testing of stone material and multiple handling of the stone—significantly reducing the potential for breakage.
The contractor calculated the precise number of trucks required to maximize productivity on a given day, staggering vehicles to reduce traffic and back-ups on site.
Trades used a GPS-enabled excavator to place armor stone and a GPS-enabled bulldozer and grader to place core stone and gravel. Along with highly skilled labor, GPS allowed team members to achieve placement well within specified tolerances.
Crews worked year-round, including during a winter beset by icy roads, ice build-up and snow that strained workers and equipment alike. Experienced operators were critical to completing the project 1 and ½ years ahead of schedule, team members say.
Once the islands are fully restored, the Corps expects they will strengthen lower Green Bay's ecosystem and promote diversity among migratory birds and aquatic species. The islands previously supported more than a dozen species of colonial nesting birds that may return once the infrastructure is in place.
Cat Islands Chain Reconstruction, Green Bay, Wis.
Owner U.S. Army Corps of Engineers, Kewaunee, Wis.
General Contractor Michels Corp., Brownsville, Wis.
Designer U.S. Army Corps of Engineers, Kewaunee, Wis.