The most common types of dredging projects

When thinking about dredging, eye-catching developments such as the construction of the Suez Canal and Palm Island in Dubai come to mind. These projects have shown the enormous possibilities and potential that dredging has to offer. The Suez Canal meant a shorter shipping route between the East and Europe and has boosted the global economy. Palm Island is an example of how we are able to shape our own environment. Although great examples, these two projects only show a fraction of what dredging is about. Dredging has many applications, both large and small. Among the most common are:

Port or harbour construction

Growing global trade has led to an increase in maritime transport. In order to accommodate this growth in international shipping and ever larger vessels, new ports are being constructed around the world and existing port infrastructure is being expanded. Dredging activities for port construction and expansion include the creation of access channels, berthing places and turning basins, reclaiming land for yard and terminal activities, and the deepening and widening of existing waterways.

Port and estuary maintenance         

Ports and estuaries are under constant threat of siltation. Tidal movements deposit sand and silt from the sea in port basins and waterways. Rivers also carry sediment in their flows, which tends to settle in  deltas. Due to these natural phenomena, the water depth gradually decreases. In order to safeguard a constant navigable depth, maintenance dredging is required.

Land reclamation 

The overall growth in the global population and the trend of migration towards coastal areas has led to a huge rise in the number of land reclamation projects. Industrial sites, residential areas, ports and airports are increasingly expanding in the direction of the water. The dredging process uses sand, clay or rock from the seabed to create new land elsewhere. Many land reclamation activities are combined with projects for deepening of ports and access channels, since the reuse of the dredged materials for adjacent jobs may reduce the total costs.

Coastal protection

Coastal protection is an essential process to provide a defence against flooding and the erosion of land caused by waves, tides, currents and wind. The trend of migration towards coastal areas, rising sea levels and climate change will further increase the need for coastal defence. Beach re-nourishment and dike construction are some examples of coastal protection works. Both require the recovery and transportation of large volumes of sand.

Offshore trenching

Offshore power cables, pipelines and umbilicals are buried in the seabed to keep them in place and protect them against heavy objects. Dredgers are used to create a trench in which the cable or pipeline is then buried. As these offshore dredging activities require absolute precision, the vessels used for this specific purpose are equipped with highly accurate positioning instruments and facilities for dynamic positioning and dynamic tracking.

Environmental dredging

Environmental dredging targets polluted materials in sections of ports and rivers, often within industrial areas. These remediation projects require accurate dredging, low generation of turbidity and low spillage in order to remove contamination without harming the surrounding environment.

Lakes and reservoirs construction and maintenance

With an increasing demand for clean energy and drinking water, the construction of water reservoirs and lakes used for hydropower is on the rise. Dredging also tackles the growing problems of aquatic weed infestation and excessive sedimentation in existing water reservoirs, improving the availability of clean drinking water and the reliability of the power supply.

Dredging for sand and gravel

Marine aggregates, such as sand and gravel, play a crucial role in modern day life. These natural resources are widely used in the construction industry and, with the global population rising, the demand for construction aggregates is also increasing. Dredgers are deployed to collect and transport the sand and gravel  from offshore extraction areas.

Mining

Dredgers are used for wet excavation in the mining industry. Dredgers excavate the natural resources from a river, near shore or from man-made ponds and pump them directly into mining separation plants for processing.