Dredging Around Coral Reefs

“Facts About Dredging Around Coral Reefs” describes the strategies and care needed to preserve and protect coral reefs during dredging activities.

Coral reefs are large, long-lived bio-geological structures that are marine ridges or mounds. They are formed from the deposition of calcium carbonate by living organisms, predominantly hard corals, but also by other organisms such as coralline algae and shellfish.

Although coral reefs are robust and have often withstood the forces of storms, climatic change, sea level change and predators, the living elements – coral, coralline algae and shellfish that build these structures – are just a very thin veneer of delicate tissue, highly sensitive to the surrounding environment.

Why should coral reefs be protected? Healthy coral reefs provide an array of services to human communities, including food (especially protein), protecting shorelines, supporting the livelihoods of local communities, such as fishing and tourism, and sustaining cultural traditions.

Dredging can impact coral reefs because of the composition of the reefs themselves. Limestone and coral materials tend to break into extremely fine particles when dredged, which creates milky white “clouds” of suspended sediments. These fine clouds of sediments can stay in suspension for a long time, spreading over a large area and often causing increased sedimentation that results in significant light reduction. This makes it critical to avoid or at least to minimise the dredging of coral rock.
Dredging contractors are well aware of the delicacy of dredging in coral reef areas. They strive to find methods to mitigate the dangers of damaging corals during operations, such as removing and replanting the coral. Monitoring before, during and after a project near coral reefs can also help quantify risks. To create a successful dredging project in a sensitive coral reef environment demands that all parties involved work with transparency, with a clear understanding of the issues, and with a strategic management plan.

“Facts About Dredging Around Coral Reefs” answers essential questions such as:

  • What are Coral Reefs?
  • Why are Coral Reefs important?
  • Where are Coral Reefs found?
  • Why study the interaction of Coral Reefs and Dredging?
  • Why is it difficult to dredge near Coral Reefs?
  • How and when does dredging impact Coral Reefs?
  • Do all Corals suffer when dredging impacts them?
  • If Coral Reefs suffer losses, are they permanent?
  • Can Coral Reefs be preserved and protected during dredging?
  • How can sound strategic planning protect Coral Reefs?
  • What are key activities that should be undertaken during the planning process?
  • How can impacts to Coral Reefs be mitigated and/or compensated?
  • Can Coral Reefs recover from impacts during dredging?
  • What best technical practices can be used to prevent, minimise, mitigate and/or compensate impacts, when dredging near Corals Reefs?
  • What is an EMP and how can it help?
  • Can monitoring help protect Coral Reefs?