Typically, about 4 million cubic yards of sediments are dredged by the Corps of Engineers each year from Great Lakes harbors and channels, the equivalent to 400,000 truck loads of soil. Detroit (harbors in Michigan, Wisconsin and Minnesota)ĭredging and the management of dredged material are an important function of Corps districts.

Chicago (harbors in Indiana and Illinois).

Buffalo (harbors in New York, Pennsylvania and Ohio).

Great Lakes harbors and channels are maintained by the Corps' districts in: In order to maintain channels and harbors at safe depths, periodic dredging is required. This is especially common at harbors where commercial navigation is concentrated near the river mouth while recreation traffic extends a distance upstream. The channels at a particular harbor may have depths up to 30 feet at the entrance with progressively shallower depths as one moves upstream. In contrast, the Connecting Channels between the Great Lakes are maintained at depths of 30 feet for the ocean-going ships which carry ore, coal, and other cargos between domestic and international ports. The navigation channels on the Mississippi and Ohio Rivers are maintained at authorized depths of 9 feet, which is sufficient for the barges and cargo they carry on these rivers. The depths of channels vary with the types of traffic. These harbors and channels were constructed to serve commercial navigation, recreational navigation, or both.Ĭhannels and harbors are maintained for safe navigation. Most of these navigation authorizations date from the early 19th century. A 'Federal' channel or harbor is one that has been authorized by Congress.

There are 136 Federal harbors within the Great Lakes Basin, with 745 miles of navigation channels.

Boston harbor dredging great lakes 1998