Offshore Waters

Key Characteristics

    • Simple bathymetry of consistently deep waters, generally in excess of
    • Seabed is characterised by relatively undisturbed
    • Wide areas designated, or proposed for designation, due to their wildlife Sandbanks form important habitats.
    • Busy shipping waters with several established commercial shipping
    • Commercial fishing activity, including from larger
    • Industrial activity includes dredging for aggregates and offshore wind
    • Large military practice
    • Visually Consistent panoramic horizons across extensive tracts of sea.
    • Wild and isolated qualities although views to large vessels, dredging activity and offshore wind turbine arrays become important points of orientation in an otherwise vast and featureless
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The Offshore Waters SCT lies seaward of the Coastal Waters SCT at a distance of approximately 18km (9.7nm) from the coastline, extending to the seaward extents of the study area.

Physical Influences

The bathymetry of the Offshore Waters SCT is relatively simple and generally in excess of 30m in depth becoming shallower towards landward and seaward limits of the SCT.

The seabed is characterised by a mix of relatively undisturbed sand and gravel sediments and the bedrock is rarely exposed on the seafloor. Sediments include those laid down by ancient river channels prior to the formation of the North Sea. Curving sandbanks running parallel to the coastline are of particular note north of Great Yarmouth.

A significant proportion of the Coastal Waters SCT is designated (or proposed for designation) for its nature conservation interest. It forms part of the Southern North Sea Candidate SAC, Margate and Long Sands SAC and part of the Outer Thames Estuary SPA. Also, within the Offshore Waters SCT, are parts of the recommended MCZs of Orford Inshore and Kentish Knock East. These are dominated by habitats composed of subtidal mixed sediments which are important as nursery and spawning grounds for many fish species, including commercially fished species such as cod, plaice, sole, mackerel and herring.

Species of burrowing anemones can also be found within the sediment, alongside sea cucumbers, urchins, starfish and several nationally important shark species, including the small-spotted catshark. The area is also important for foraging seabirds and harbour porpoise can also be seen passing through. Sandbanks north of Great Yarmouth fall within the Haisborough, Hammond and Winterton SAC.

Cultural Influences

There is potential in the offshore sediments for evidence of the communities and landscapes that occupied the area prior to the formation of the North Sea. There are also several wrecks, including two designated under the Protection of Military Remains Act. These are the HMS Exmoor, which was sunk by an E-Boat approximately 22km (12nm) east of Lowestoft in 1941 whilst escorting a convoy and the HMS Amphion located 65km (35nm) east of Dunwich.

The Amphion won the first victory of the war but was itself wrecked the following day by one of the mines laid.

The Offshore Waters SCT contains several busy deep-water shipping routes for cargo vessels, tankers and passenger ships. These vessels transit between major European and UK ports and the English Channel.  The density of vessel movements is particularly high where routes leading to and from the Straits of Dover intersect with east west routes between Harwich/Felixstowe and Dutch ports. In the busy waters east of Harwich Haven anchorages and shipping routes are marked by navigation buoys.

The Offshore Waters SCT includes some of the UKs most important marine aggregate resources and licenced dredging areas and there are numerous oil and gas wells recorded in the northern portion of the SCT (north of Lowestoft). East of Felixstowe is the operational offshore windfarm of Greater Gabbard. There are also offshore turbine arrays under construction at Galloper and east Anglia One. Vessels associated with the transit of plant and supplies for the construction, operation and maintenance of offshore infrastructure and other operations are noted.

Like much of the North Sea these waters are rich commercial fishing grounds and the benthic habitats support extensive spawning and nursery areas for a variety of commercial fish species. Activity includes bottom trawling, dredges and mid-water trawling, as well as the use of static gear (lines, nets and pots). A number of UK vessels are active within this area, targeting species such as sole, bass, and cod, and whelks. Larger vessels from France, Belgium, The Netherlands and Germany are also active (up to the 12nm UK territorial waters limit) and a variety of gear types are used to target species including dover sole, and plaice.

Military use of the Offshore Waters SCT includes munitions dumping grounds approximately 20km (11nm) east of Orford and part of extensive military practice areas east and south east of Felixstowe. These are areas in which naval, military or aerial exercises are carried out.

Aesthetic and Perceptual Qualities

The Offshore Waters SCT is visually unified with consistent and extensive panoramic horizons. The vast scale of the seascape and distance from the coast imparts a wilderness quality and sense of isolation, which becomes more pronounced in poor weather.

Within the context of an open and largely natural seascape, offshore wind turbines and vessels at anchor or in transit are often the only cultural cues. Subject to conditions, wind turbines can be visible for great distances and are typically the only fixed points of orientation and scalable visual references. Container ships and tankers, smaller vessels often associated with servicing offshore industries and fishing boats are also visible, although sea mists and swell can limit their visibility.