Image – Generated

Sizewell C’s Marine Access: Permanent BLF, Wide Temporary Jetty, Narrow Temporary Jetty.

What is being built or authorised

1) The permanent Beach Landing Facility

The Sizewell C Development Consent Order includes a permanent Beach Landing Facility (BLF) to bring in abnormally large loads that cannot sensibly come by road. The BLF is authorised for both the construction phase and long-term occasional use during the station’s life.

Key points from the planning record

• BLF is a fixed, engineered structure with a small footprint compared with a full multi-berth jetty, intended primarily for exceptional heavy lifts.
• It is the retained marine access after the temporary works are removed at the end of construction.

2) The wide temporary jetty

Consultation documents describe an approximately 800 metre long temporary jetty with two northern berths for bulk materials and potential export of excavated material, plus one southern berth for very large loads. The support structure is open to reduce hydrodynamic effects. Removed after construction.

3) The narrow temporary jetty

An alternative narrow jetty was consulted on. It keeps an open support structure and can handle abnormally large and general cargo deliveries, but cannot convey bulk aggregates or spoil. It also has a simplified head since conveyors are not needed. Removed after construction.

Why you will hear “three options”

The Stage 2 consultation framed three sea-transport options during construction

1. Wide jetty
2. Narrow jetty
3. Use of the BLF during construction
   The DCO then locks in the permanent BLF and the ability to deploy temporary marine works for construction logistics.

Suffolk east coast setting that drives design choices

Tides and sea state

• Local documentation cites a spring tidal range of roughly 2.1 metres at Sizewell. That figure is used in modelling submissions and is a sensible planning datum for clearances and mooring analysis.
• Public tide tables for Sizewell Beach show typical highs around 2.3 to 3.0 metres and lows near 0 to 0.7 metres on ordinary days, which aligns with the above range. Do not use hobby sites for design, but they show the ballpark pattern seen on site.

Longshore drift and shingle behaviour

• Historically the Suffolk coast shows net southward longshore transport of sand and shingle, building the classic ridges and spits.
• More recent studies and local evidence note periods of reversal or variability in drift direction, driven by wave climate shifts and bathymetric change. Translation for operations: sediment pathways are not one-way or perfectly predictable year to year.
• The shoreline around Sizewell is a shingle-backed beach with low cliffs in places and sensitive vegetated shingle habitats inland of the active ridge. That limits how and where landward tie-ins, access tracks, and shore protection can be formed.

Mooring arrangements that are plausible for each structure

Explicit that it is informed speculation.

Permanent BLF

What the record supports

• A fixed landing structure for occasional heavy lifts, modelled alongside the temporary BLF or jetty variants during examination.

Informed speculation on moorings

• Pile-supported berth with mooring and breasting dolphins either side of a short head. Dolphins would be steel tubular piles with fender panels to take berthing energy.
• Quick release hooks on the berth face and dolphins, with capstans sized for windage of heavy-lift ships or barges.
• Berthing energy managed by high-efficiency fenders rated for the design vessel and a conservative approach speed, given open coast exposure.
• Heavy lift interface likely via a ro-ro ramp or SPMTs from a reinforced deck, or a temporary jack-up or sheerleg crane moored off the head when single lifts are needed.
• Aids to navigation inshore, with seasonal adjustments if sediment ridges migrate.

Wide temporary jetty

What the record supports

• Approx. 800 m long, multiple berths, conveyors for aggregates and the option to offload or reload excavated materials, open piled support to limit flow blockage. Removed after use.

Informed speculation on moorings

• Continuous pile-supported deck with integral mooring points and separate mooring and breasting dolphins at each berth to keep bow and stern lines fair and maintain stand-off for fenders.
• Berths split by cargo type
  • Northern side: bulk carriers or self-discharging coasters. Expect shore bollards at 15 to 25 m spacing and conveyor-aligned chutes.
  • Southern side: abnormal load berth with lower motion criteria, possibly using multi-point mooring plus tug attendance during cargo operations.
• Storm readiness
  • Hinged or demountable conveyors and removable galleries so sea states cannot wreck fixed kit.
  • Design for wave transparency using pile bents rather than large solid faces to avoid scour and reflected wave problems.
• Temporary navigation buoys to mark approach channels and turning areas during construction seasons.

Narrow temporary jetty

What the record supports

• Open piled, simplified head, no conveyors, still suited to abnormal and general cargo. Removed after use.

Informed speculation on moorings

• Fewer dolphins and a shorter jetty head means tighter operational envelopes. Expect limits on vessel size and metocean windows.
• Use of jack-up barges or spud barges alongside for lift stability when placing large plant modules, with breasting fenders on the head and spring line geometry tuned to hold position without excessive line loads in veering winds.
• Rapid demobilisation features so the whole head can be stripped quickly before winter storms.

Tidal resilience and scour on a shingle coast

Design implications from the Suffolk coast setting

• Open pile arrangements reduce blockage and minimise local scour compared with solid jetties, which is exactly why the consultation emphasised open support structures.
• Scour countermeasures likely include rock aprons or fronded mattresses around pile groups at the BLF and berth heads, sized for spring tide currents and storm wave-induced orbital velocities. This is standard good practice for open coast berths.
• Allowance for variable longshore drift means designing with some tolerance for bed level change at the toe of fender panels and dolphins, with adjustable fender work or pile sleeves to keep contact geometry correct as beaches migrate.
• Tidal range around 2.1 m springs sets the minimum and maximum berth deck elevations, ladder lengths, gangway accommodation and the fender panel vertical span to keep vessels within the working fender line through the tide.

Operations and weather windows

• Expect metocean operating limits set by significant wave height, period, wind, and current. Bulk discharge can tolerate more motion than precision heavy lifts at the BLF.
• Seasonal operations make sense. The highest downtime risk is winter northeasters pushing short, steep seas onshore across a relatively shallow nearshore shelf.
• With variable drift in recent years, sustained northerly wave climates can push material northwards for a season, affecting toe levels around piles. This is planar reality, not theory. Factor in more frequent bed surveys in the first seasons to validate the model.

Environmental and planning context to keep in view

• Vegetated shingle is a sensitive habitat, and piling plus shore tie-ins must avoid unnecessary disturbance. Expect method statements to commit to narrow working corridors and reinstatement.
• Landscape assessments for the BLF highlight adverse visual and landscape effects during construction and operation, which is why temporary works are removed and the BLF is kept as compact as possible.
• The DCO portal and certified control documents hold the current versions of method statements, codes of construction practice, and marine controls. Always check those documents before quoting numbers in public.

What to watch for in the final detailed design releases

• Definitive berth elevations and fender energy ratings for each jetty face
• Design vessel list including LOA, beam, displacement, approach speeds, and windage
• Scour protection drawings around dolphin groups and jetty bents
• Sediment monitoring plans and triggers for maintenance dredge or shingle redistribution around the BLF
• Navigation risk assessments and aids to navigation layouts issued to Trinity House

Summary

• The permanent BLF is the long-term marine access point.
• A wide temporary jetty supports high-throughput bulk and heavy lifts during construction.
• A narrow temporary jetty offers a lighter logistics footprint if bulk by sea is reduced or handled elsewhere.
• On a shingle coast with variable longshore drift and a spring range about 2.1 m, open-piled structures with robust dolphins, conservative fendering, and scour allowances are the sensible choice.

Sizewell C Stage 2 consultation summary and marine transport proposals

Development Consent Order and supporting environmental statements

Tidal data and modelling submissions for Sizewell spring range

Suffolk Coastal processes and longshore drift studies

Landscape and visual impact assessments for the Beach Landing Facility