banned in 2008, back into the water. The nature of dredging operations and possible environmental impacts cause the industry to be closely regulated and a requirement for comprehensive regional environmental impact assessments with continuous monitoring. The U.S. Clean Water Act requires that any discharge of dredged or fill materials into "waters of the United States," including wetlands, is forbidden unless authorized by a permit issued by the Army Corps of Engineers. As a result of the potential impacts to the environment, dredging is restricted to licensed areas only with vessel activity monitored closely using automatic GPS systems. Major dredging companies According to a Rabobank outlook report in 2013, the largest dredging companies in the world are in order of size, based on dredging sales in 2012 China Harbour Engineering (China) Jan De Nul (Belgium) DEME (Belgium) Royal Boskalis Westminster (Netherlands) Van Oord Dredging and Marine Contractors (Netherlands) National Marine Dredging Company (United Arab Emirates) Great Lakes Dredge & Dock Company (United States) Notable dredging companies in North America Manson Construction Co. (United States) Notable dredging companies in South Asia Dredging Corporation of India Adani Ports & SEZ (India) Images See also Chemistry of wetland dredging Dredge ball joint, connection between 2 pipes that are used to transport mixture of water and sand from a dredger to the discharging area Dredge drag head Dumping of dredged sediment in Long Island Sound Navigability Peace in Africa (ship), a diamond-mining dredger Queen of the Netherlands (ship), a big dredger River engineering for inland dredging and other river management systems WT Preston, a snagboat Foreign Dredge Act of 1906, a US law banning foreign-built and foreign-owned dredges from operating in US waters Gold dredge References External links Directory of Dredgers (a close to exhaustive private collection of dredger photographs) Dredging and Spoil Disposal Policy (from the Australian Government) The Art of Dredging (Knowledge sharing) International Association of Dredging Companies Knowledge centre World of Boats (EISCA) Collection ~ Isambard Kingdom Brunel's Bertha Engineering vehicles Coastal construction Nautical terminology Coastal engineering de:Baggerschiff