These are modern dredgers and can avail efficient dredging. Then came cutter suction dredgers and trailing suction hopper dredgers in the 19 th century. From then on, dredging by suction became more and more common. He successfully used this suction dredger in dredging the Suez Canal. In 1867 there came a revolutionary development with the evolution of the design of a suction dredger by a French engineer. Mills had gone obsolete in 1857 with the development of a suction dredger in the United States. Mills had a rotating chain connected with wooden boards, and these wooden boards dug up the mud.Īt the primary stage of the development of mills, they were manually driven later. These were a sort of dredging equipment used for digging in ports. These dredgers developed from ancient mills to modern suction dredgers. These bed levellers cum scratchers were used to pick the sediments and dispose of them. In the 15 th century, increased trade at seas necessitated the development of some bed scratchers such as “Zeeuwse Krabbelaar”, which was a primitive bed leveller. Still, due to a lack of equipment for removing siltation, they started manually digging the mud by hand, which was not that efficient and limited to shallow waterways. People started fighting the problem of siltation to ensure the safety of voyages. Silting, the natural phenomenon of deposition of silt and sediments over the sea bed, created a constant threat to the voyages of ships. But this transportation depended on the ability of ships, which in turn largely depended on the water depth. With the beginning of civilization, commodities were transported by inland waterways and oceans. The process is a blended essence of the following three independent elements: excavation, transportation of excavated material and then usage or proper disposal of dredged material. The Lowlands of the Netherlands and Flanders are the best example of regions requiring regular maintenance dredging.įor dredging, dredgers are used to remove the deposited sediments from an inlet creek, waterway or ocean floor. Regular maintenance dredging is of enormous importance in coastal regions with sizeable tidal activity and in water bodies that are susceptible to becoming silted with sediments, sand and mud. Maintenance Dredging is a broader term that includes clearing deposits and cleaning, widening or deepening a water body using either a suction or scooping device (generally called a dredger). The oldest known dredging activities are: dredging for peat excavation and maintenance dredging. In general terms, dredging implies digging up the gathered sediments from the seabed and disposing of them at some other site. Ultimately disposal barges or dump scows empty the material at the disposal area.

The rotating cutter-bar uses its sharp blades to loosen the sediment on the bottom, and it is sucked in using a submersible pump. The dredge operator lowers it to the side of the body of water or its bottom.

It involves excavating either naturally deposited sediments or artificial debris such as rocks, bottom sediments, construction debris, refuse, and plant or animal matter on the bottom of either shallow seawater or freshwater. Once the hoppers are full, the process is halted for a while, and the ship travels to the water disposal site, where the unwanted sediments are released through the bottom of the ship. Dredging removes the deposits percolated underwater to clear the water pathway for ships to pass, creates adequate space to construct important bridges, dykes and dams and weed out silt, intoxicants and pollutants from the bottom of the water.

Dredged meaning