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Cat Island Chain Restoration Project

Green Bay, WIsconsin

Dredged materials provide environmental benefits

After decades of planning, the Cat Island Chain Restoration Project began in October 2012. Project partners, which include the U.S. Army Corps of Engineers, Brown County, Wisconsin Department of Transportation, Wisconsin Department of Natural Resources, UW-Sea Grant, UW-Green Bay, the U.S. Fish and Wildlife Service, and the Fox River Group of paper mills, have worked since the mid-1990s to design a restoration plan for the island chain using navigation channel dredged materials.

The Cat Islands were a chain of small islands that were washed away in the 1970s by high water levels, storm waves, and ice. They historically functioned much like coastal barrier islands – extending 2.5 miles into Green Bay – protecting a large expanse of shallow bay waters and wetlands that provided fish and wildlife safe habitat.

The project site is located just north of the mouth of the Fox River and involved Brown County building 3,900 linear feet of wave barrier and access road to protect the islands. The Corps have begun the construction of 4.3 miles of stone dike ranging from four to eight feet high on Green Bay lake bed and the installation of concrete culverts for circulation between islands. This will create a dredged material disposal facility (DMDF) with 20 plus years of capacity for the sediments from the lower portion of the navigation channel. Dredged materials deposited in the new DMDF will gradually build three new islands – West, Middle and East – at the location of the former Cat Island chain.

The goal of restoring the islands is to provide beneficial use for dredged materials removed from Green Bay and strengthen the lower Green Bay ecosystem while fostering the diversity of habitat for migratory birds and various fish species.  These habitats are critical in sustaining important sport and commercial fisheries, as well as providing isolation for nesting water birds from mainland predators.  In the past, the islands have supported at least 13 different species of colonial nesting birds – one of the highest bio-diversities of any Great Lakes island. When the new islands are built, it is hoped that those species will return.

Additional expected benefits include enhancing spawning grounds for fish, and wildlife viewing opportunities for the public. Long term environmental benefits are expected as well since the near shore habitat of the lower bay will be further protected from erosion caused by storm events.

The total project cost is estimated to be $20 million, with completion of the wave barrier and side dikes expected by fall 2014. More than 270 acres of upland habitat, protecting 1,400 acres of shallow water behind the islands, will be created.