What is Dredging?

Underwater excavation is called dredging. A dredge is a machine that scoops or suctions sediment from the bottom of the waterways or is used to mine materials underwater. While the instrumentation of modern dredges is computer assisted, the basic excavation methods of dredges have remained the same since the late 1800s. The two main types of dredges Local 25 members work aboard are mechanical dredges and hydrhydraulic dredges.
Mechanical dredges remove material by scooping it from the bottom and then placing it onto a waiting barge or a disposal area. The two most common types of mechanical dredges are dipper dredges and clamshell dredges. These names refer to the type of scooping buckets they employ. The dredge is mounted on a large barge and is usually towed to the dredge site and secured in by anchors or anchor pilings, called spuds. Disposal barges, called dump scows, are used in conjunction with the mechanical dredge.
Hydraulic dredges work by sucking a mixture of dredged ... [More Information]