What is a dredger?

A dredger is an aquatic machine used to extract submerged material and bring it to the surface. Dredgers can be installed on the banks of rivers, lakes, canals, seas, swamps, or other bodies of water, or operate from a boat. Dredgers should not be confused with draglines.

What are dredgers used for?

Dredgers are mainly used for cleaning, digging, and deepening aquatic floors or extracting any valuable matter sunk there. 

In construction, some of its uses include:

• Improving the navigability of waterways, ports, and berths.
• Draining areas.
• Making dykes or dams.
• Preparing ground to lay the foundations of bridges, jetties, and other structures with submerged bases.
• Regenerating beaches for recreational or ecological purposes.
• Extracting useful matter, such as sand, gravel, clay, and other materials for construction.
• Collecting mollusks and crustaceans for the food industry.
• Maintaining aquatic beds, whether natural or artificial.
• Recovering eutrophied areas or those polluted with chemical or other nature spills.

What types of dredgers are there?

Dredgers are divided into two main types: suction dredgers and mechanical dredgers. However, these two families contain a great variety of mills that serve very diverse needs.

• Suction dredgers: these have a submersible pipe with a powerful suction pump that can extract the material from the bottom. Depending on their design, they can also be:
  • Equipped with cutting blades to disintegrate matter as it passes through the mouth of the pipe.
  • Equipped with water injectors to soften the bottom to suck it up as mud.
• Mechanical dredgers: they work more like excavators. There are:
  • Crane types with a submersible scoop or with a shovel and mechanical arm.
  • Continuous hoppers, which look more like submersible trenchers equipped with a rotating wheel or chain with metal containers called buckets, with which the material is extracted from the bottom.

What are the ecological implications of using dredgers?

Many dredging processes can have a significant environmental impact, such as shaking sediment deposits that are found in the aquatic beds and destroying ecosystems that depend on the waterbed. Therefore, it is essential to carry out rigorous studies before using it to determine the feasibility of this use.