Dredging is a process used to remove deposits underwater to clear water pathways for ships to pass, weed out silts, toxins, and other pollutants from the underwater surface, and make adequate space to construct bridges, dykes, or dams. The process mainly involves the excavation of natural rocks, deposited sediments, or artificial debris, including construction debris, refuse, animal, and plant matter in the bottom of deep or shallow waters. In other words, it involves digging up gathered sediments from the seabed to dispose of them on the other side. (source:https://oceanservice.noaa.gov/facts/dredging.html)
Dredging in a nutshell
Some of the popularly known dredging activities include dredging maintenance and dredging for peat excavation. Maintenance dredging includes widening or deepening water bodies using dredgers and cleaning or clearing deposits. Maintenance dredging is especially important in coastal regions with extensive tidal activity and water bodies that are susceptible to be silted with mud, sand, and sediments.
Dredgers are used to remove deposited sediments from the ocean floor and other water bodies. The dredging process involves three primary elements:
- Transporting the excavated material.
- Proper disposal or usage of the excavated material.
The growth of dredging technology
The modern dredging vessels or equipment feature state of art technologies and come in many types from large to small ones (source: https://keelrowbooks.com/item/1153/gold-dredging-and-mechanical-excavators/). Let us look at the history of dredging technology, in a nutshell, to understand how innovative it is getting.
When civilization first began, the transportation of commodities through inland waterways and oceans started, but it relied on ships that depended on water depth to move. However, silting posed a huge challenge to the voyages of ships. Silting refers to the deposition of silt and sediments on the sea bed. People began to find solutions to siltation problems, but they would dig up silt and mud manually due to the lack of mechanical equipment. That was not effective, and it was only possible in shallow waterways.
During the 15th century, the increase in trade overseas necessitated the development of bed levelers known as ‘Zeeuwse krabelaar.’ (source: https://www.worldhistory.org/article/1301/trade-in-medieval-europe/) They were used to dig sediments and dispose of them. Their growth continued in phases to the modern suction dredgers.
There was also the development of mills, dredging equipment for digging in ports. The ancient mills featured a rotating chain with wooden boards which used to dig up the mud. The mills were manually operated in their initial stage, but they later developed to be powered by steam engines. In 1857, there was the invention of suction dredges in the US; hence mills became obsolete.
In 1867, with the evolution of the design of the suction dredger came a revolutionary development by a French engineer. He employed the suction dredger in dredging the Suez Canal, and since then, the model got popular. The 19th century introduced cutter suction dredgers and trailing suction hopper dredgers. They remain the modern dredgers that can facilitate efficient dredging. They are so efficient that they enable efficient dredging to allow shipping without causing traffic.
Recent evolutions of dredging technology
The growing innovation in dredging technology focuses more on optimizing the dredging technology than developing new dredgers. The standardization of dredging equipment and the advancement of monitoring and control systems have improved the dredging process to a great extent.
Both the small and large dredging equipment feature state of art improvements in technologies such as:
- Dredge kine components.
- Suction pipes.
- Monitoring systems.
- Dynamic position and tracking systems.
- Pumps and submersible pumps.
Summary
Dredging is an essential process in the maritime industry as it serves the following purposes:
- It is used for the extraction of ocean gems.
- To channelize the construction of civil engineering works such as bridges.
- Remove pollution for the sake of the marine ecosystem.
- Contributes to safer voyages.
- It is also used for recreational activities.
