Maintenance Dredging Of The Federal Navigation Channels In The St Marys River And Straits Of Mackinac Michigan PDF Download

The proposed action is to perform maintenance dredging of the St. Clair River when required to remove shoaling. Average annual volume removed is approximately 130,000 cubic yards consisting primarily of gravel, sand, and silt. The material removed will be disposed of deep water or placed on selected onshore sites. All materials scheduled for removal from the St. Clair River have been classified by the U.S. Environmental Protection Agency as suitable for unrestricted open water disposal. Most maintenance operations are accomplished by hopper dredge, but a derrickboat utilizing a bucket dredge removes channel obstructions if rock rather than sand or silt must be removed. The open water disposal sites used by the hopper dredge are located in the deep water of Lake Huron several miles north of the Blue Water Bridge and during 1976 in deep water of the North Channel adjacent to Point Au Chenes. The use of the North Channel disposal area will be discontinued after the 1976 work season. In subsequent years sediments removed from the lower reaches of the river will be stockpiled at an onshore site furnished by the Michigan Department of Natural Resources for future project was uses in maintenance and further development of the St. Clair Flats Wildlife Area. (Author).