Dredging Methods Video

This video demonstrates various dredging methods including mechanical dredging, hydraulic dredging, and hydrodynamic dredging. Mechanical methods presented include clamshell, backhoe, bucket ladder, and dragline; hydraulic dredging methods presented include cutter head and plain suction.

Video – Dredging Methods [19:45]
This brief video presents an overview of various dredging methods including mechanical, hydraulic, and hydrodynamic dredging.

Dredging Methods

Dredging processes can be split into two main groups or types. This classification is dependent on the method by which the specialized equipment transports sediment and other materials. The two main types of dredgers are mechanical and hydraulic dredgers.

Mechanical Dredger

Mechanical dredges work by mechanically digging sediment from the bottom surface of a water body. It transports the loosened material to the surface through the use of a bucket, clamshell, or other means. Mechanical typically dredging takes place at the shoreline or off a barge. This type of dredging is conducted in a full column of water and does not involve draining the water body.

Types of mechanical dredges

Bucket Dredger
This is one of the oldest dredgers in existence. It is a stationary dredger which is fixed on anchors. Its movement is facilitated by winches that swing the platform in semi-arcs around the anchor. It got its name from the fact that it is equipped with an endless chain of buckets that fill while scraping over the bottom.
Grab Dredger
This is an immobile dredger that is secured on anchors. The grab dredger is made of two shells that are operated by wires. The shells are mounted on a dragline of the backhoe type. This type of dredger is used in harbors.
Hydraulic Dredger
Dredgers in this category lift the loosened material through a pipe system. The material is sucked by a centrifugal pump. This form of dredging is best when working with fine materials because they can easily be held in suspension.

Types of Hydraulic Dredgers

Suction Dredger
This is a stationary dredger that is used to mine sand. The suction pipe is pushed vertically into a sand deposit and it handles the rest.
Cutter Suction Dredger
This is a stationary dredger. It is fitted with cutter heads which loosen the material to be dredged. The dredger has a pump that facilitates the transportation of the dredged material via a pipeline ashore. The cutter heads on this dredger are interchangeable and can be replaced depending on what is being mined.

Dredging Continuing Education Courses

If dredging and the management of dredged materials is of interest to you, consider our continuing education courses that address this subject directly.

EN-02-600 Dredging and Dredged Material Disposal – 6 PDH
This course presents engineering and design guidance for use on new dredging projects as well as maintenance work. It provides an inventory of the dredging equipment and disposal techniques used in the United States and provide guidance for activities associated with new work and maintenance projects.

EN-02-600W Live Webinar: Dredging and Dredge Material Disposal – 6 PDH
This Live Webinar course presents engineering and design guidance for use on new dredging projects as well as maintenance work. It provides an inventory of the dredging equipment and disposal techniques used in the United States and provide guidance for activities associated with new work and maintenance projects.