What is dredging? Underwater excavation is called “dredging.” Usually when people think of “dredged material,” they imagine the murky water from the sediments stirred up in the process of dredging a river, waterway or wetland. For example, the Army Corps of Engineers (Corps) is beginning the work of dredging the Kennebec River in midcoast Maine to allow a 510’ warship built by Bath Iron Works to be transported safely down the river. Because this project is happening at the height of summer (and tourist season) and not in the winter, several petitions cried for a halt of the project. But the Maine Board of Environmental Protection and a federal judge rejected those petitions.http://boatinglocal.com/news/kennebec-river-being-dredged-to-allow-warship-passage.html
What most people don’t realize is that sometimes the Corps uses dredged material to restore coastal and wetland habitat. Depending on the type of sediment—rocky, gravel & sand, consolidated clay (hard and soft clay), silted/soft clay, or a mixture of these—there are a number of ways that dredged material can be used beneficially. Some applications include berms, shore protection, aquaculture, beach nourishment and replacement fill.
On the west coast, the Southwest Washington Littoral Drift Restoration Project, a state-federal collaborative effort, is evaluating the beneficial use of dredged material at Benson Beach (WA). http://news.opb.org/article/north_cove_could_be_all_gone_by_2053/ In Florida, there is a potential project using Section 204 funding for beneficial uses of dredged material in the Destin area. http://www.thedestinlog.com/news/point-18557-norriego-funding.html
After the Gulf Oil spill, President Obama signed a bill in 2010 to allow for funding for the use of beneficial dredged material for coastal restoration in the Gulf.http://landrieu.senate.gov/mediacenter/pressreleases/07-29-2010-2.cfm
The Coastal & Hydraulics Laboratory within the Corps is one of the lead organizations doing research on beneficial use of dredged material.http://chl.erdc.usace.army.mil/dredging One of their active projects is the SuperDustpan Beneficial Use Project in the Mississippi River. For their 2004 technical report, go to:http://chl.erdc.usace.army.mil/chl.aspx?p=s&a=PUBLICATIONS;220
When coastal estuaries and islands erode, one option to restore the coastline is beach nourishment. This means replacing sediment. Dredged material is commonly used for “beach nourishment” projects, for example, in the Gulf shipping channel (near Texas) by South Padre Island http://www.dredgingtoday.com/2011/01/31/usa-dredger-alaska-to-speed-up-brownsville-shipping-channel-dredging/
EPA has a number of resources to help in evaluating “beneficial use of dredged material” for the purpose of beach nourishment here:http://www.lrd.usace.army.mil/navigation/glnavigation/dredgedmaterialmanagement/#beachEPA has also been involved in dredged material management projects:http://water.epa.gov/type/oceb/oceandumping/dredgedmaterial/dumpdredged.cfm
The use of dredged material is a contentious issue because sometimes the sediments are contaminated, or the projects fail to serve their purpose. It is important to use clean dredged material. The links below go to more information.
Port of Portland Disposing of Contaminated Dredge Material on West Hayden Islandhttp://audubonportland.org/news/dredge
EPA’s Contaminated Sediments Program
http://www.epa.gov/glnpo/sediment/gltem/backg.htm
Dredged material as a resource http://www.iadc-dredging.com/index.php?option=com_content&task=view&id=136&Itemid=322#
Waste to Resource: Beneficial Use of Great Lakes Dredged Material
http://www.glc.org/dredging/publications/benuse.pdf
Around the country, other organizations (state, federal, regional coalitions and nongovernmental partners) are exploring beneficial uses of dredged material. For example, the Great Lakes Dredging Team—a partnership of state and federal agencies—are committed to assuring that dredging in channels within the Great Lakes is done in a timely manner that also meets environmental protection, restoration and enhancement goals. This team has a number of references available on its website for several applications of beneficial use of dredged material, including reclaimed mines and beach nourishment. http://www.glc.org/dredging/benuse/benuse.html
From a global perspective, beneficial use of dredged material is a growing area of research and technology. The international organization, PIANC, http://www.pianc.org/is the World Association of Waterborne Transport Infrastructure, and has been involved with several research projects on this topic. For more information on understanding dredge & fill permitting programs, visit: http://aswm.org/wetland-programs/dredge-and-fill-permitting-programs/127-resources-on-understanding-dredge-a-fill-permitting-programs
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