How will the channel be deepened?

27 September 2021

The harbour and channel will be deepened mainly using trailer hopper suction dredgers (TSHD) which suck material from the sea bed as they move slowly through the water.

TSHDs are self-contained dredging units which pump sediments from the sea bed via a suction pipe or pipes (2), into an inboard hopper. Whilst slowly moving forward, the vessel loads, with the suction head (1) of the pipe suspended at a predetermined level. As the dredged material settles within the hopper (3), excess water (taken on board during suction activity) is overflowed from the hopper. When the hopper reaches capacity, the dredger proceeds to the disposal ground where the dredge
material is released through bottom  doors.

It is likely that a small amount of hard dredging will be done with a backhoe dredger – a large excavator on a pontoon, loading into barges, for disposal at sea.

The works will be regularly surveyed to ensure no over-dredging occurs and that all disposals are placed within the licensed site.

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