Dredging, the excavating or scooping out of soil, mud, sand or rock under water by a machine called a dredge. Dredging is used in deepening and widening the beds of rivers, canals, harbors. The forms of modern dredges are very numerous, different conditions requiring different forms.
Chandler B. Beach The New Student's Reference Work for Teachers Students and Families (Chicago, IL: F. E. Compton and Company, 1909)
Courtesy the private collection of Roy Winkelman