What is Dredged Material?
Dredged material is material is any material removed from the bed of a water. Dredging is used to keep Great Lakes ports and harbor operable and thriving to help maintain efficient navigation, ensuring the maintenance of the vitality and operations of the ports and harbors. It can also be used to remove contaminated sediments. There are several ways to manage it, including open water placement, beneficial use and confined disposal.
More Information About Dredged Material
Open Water Placement
Open water placement of dredged material is the placement of dredged material directly in a river or a lake. It has historically been the most common practice for managing dredged sediment in the Great Lakes. It is often the least cost alternative when the sediment is determined to be clean enough for placement in the open waters of the lake. Currently some 30 – 50 percent of sediment dredged from Great Lakes harbors and channels is transported for placement in the open waters of one of the Great Lakes.
Great Lakes states and stakeholders have advocated for more protective policies, including outright bans, on open water placement. The GLDT has long been committed to serving as a forum for collaborative resolution of these differences.
Beneficial use of dredged material is the placement or use of dredged material for some productive purpose. It may involve either the dredged material or the placement site as the integral component of beneficial use.
There are several applications of beneficial use:
- Beach nourishment
- Land creation and improvement
- Replacement fill
- Construction materials
- Top soil enhancement
- Habitat restoration and enhancement
- Fisheries improvement
The GLDT places high priority on exploring value-added, sustainable dredged material management practices aimed at recycling dredged material as a useful commodity when possible, rather than managing it as a waste product.
More Information About Beneficial Use of Dredged Material
- Beneficial Use of Dredged Material in the Great Lakes (2015 poster)
- Beneficial Use of Dredged Material in the Great Lakes (2013 brochure)
- Annotated Bibliography
Confined Disposal Facilities
Confined disposal facilities (CDFs) are secure structures where the sediment is physically contained. This method of disposal is employed when open water placement and beneficial use are not possible.
More Information About CDFs
Environmental windows are periods of the year when dredging and open water placement may be carried out in a way to protect fish spawning activity and species living at the bottom of the lakes, and in some cases to prevent damage to coastal infrastructure.
The GLDT has facilitated ongoing research and dialogue with states on this issue dating back to creation of a multi-disciplinary Windows Advisory Team in 1998.
More Information About Environmental Windows
Click here to see the case studies carried out by the Great Lakes Dredging Team