Dredging is a method of excavation of materials or valuable resources which are partially or fully submerged under water.

The dredge usually consists of a boat or barge equipped with an excavator (e.g., a bucket or suction pump) and processing unit(s). Material is moved from the water body bed to the dredge, and then processed onboard (e.g., separation of particles of desired size, densities, etc.) before being moved to its onshore location.

Figure: Dredges are mining equipment on boats/barges that mine mineral below the surface of the ocean, lakes, ponds, or even man made bodies of water.