What describes the gathering of bottom sediments carried out underwater in shallow areas?

The gathering of bottom sediments underwater in shallow areas is best described as dredging. Dredging involves the removal of material from the bottom of bodies of water, such as rivers, lakes, and coastal areas. This process is usually done to maintain or deepen navigation channels, remove debris or contaminants, or gather construction materials like sand and gravel.

Dredging specifically targets sediments on the seabed or riverbed, making it an essential activity for various maritime operations and coastal management. This technique is distinguished from other processes, such as excavation, which typically refers to the broader act of digging and removing earth or soil, often on land rather than underwater. Harvesting and mining, while they involve the collection of resources, do not specifically pertain to sediments in aquatic environments in the same context as dredging does.