Sizewell C Stage 3 Pre-Application Consultation Sizewell C Coastal Event 22nd January 2019, 1300-1600 High Lodge, Darsham.
Presentation Summary ▪ Focus of presentation is on coastal process issues. ▪ Recap current SMP policy. ▪ Review progress on concerns from stage 2. ▪ Identify the priority issues from stage 3. ▪ Highlight what further information is required. ▪ Share concerns to support a stage 3 response. ▪ Agree next steps.
Minsmere Sluice SMP recognises changing coast active embayment Sizewell B Outfall Sizewell C N
Dunwich Cliffs to Thorpeness (SMP 7; Jan 2010) Thorpeness Sizewell A & B Minsmere embayment Minsmere Sluice
MR MR Sizewell SMP policy Summary
Preferred Policy to Implement Plan (SMP 7) Present day Maintain Minsmere Sluice and develop managed realignment to the north end of Minsmere. Medium Term Adapt but maintain the sluice and manage realignment to the north end of Minsmere. Consider improving flood defence within the Minsmere Valley. Long Term Adapt but maintain the Minsmere Sluice (subject to this not impinging on sediment movement and manage realignment to the north end of Minsmere. Potential need to reinforce defence at Sizewell Power Station.
Review of Stage 2 Concerns • How EDF has responded to the consultation stage 2 concerns of SCC and SCDC is in the Handout sent by email on 18/1. • The SCDC provisional updated position taking account of new EDF information is shown. • The focus by SCDC to date is on Coastal process issues. • SCDC will comment on other matters in due course.
Stage 3; Primary Concerns (CPA) 1: Impacts on nearshore coastal processes of Beach Landing Facility ( BLF ) and Fish Recovery Return ( FRR ) / Combined Drainage Outfalls ( CDO ). 2: Impacts of hard defence exposure on alongshore sediment transport. 3: Risk posed by incomplete design and seaward position of hard coastal defences.
1: Impacts on nearshore coastal processes of Beach Landing Facility ( BLF ) and Fish Recovery Return ( FRR ) /Combined Drainage Outfalls ( CDO )
1.1 Impact of BLF Outer sand bar Barge Potential Rock platform.
1.2 Example BLF
1.3 Impact of nearshore outfalls Figure 2.16.1 Proposed marine infrastructure
1.4 Station B salient B Station outfall `salient’
2: Impacts of hard defence exposure on alongshore sediment transport
2.1 Proximity of defences to shoreline
2.2 Profile of defences
2.3 Potential shoreline change Green – indicative existing coast line. Not to Scale. Red – SCDC estimated / indicative future shoreline with Sluice intact. (Detailed forecast shoreline assessment by EDF not yet available). Net sediment flow is N-S but large variations S-N are possible. Minsmere Sluice B A C Fuel store is at back edge of C station site.
2.4 Monitoring and Mitigation Development of a Monitoring and Mitigation plan that: ✓ Requires comprehensive data gathering. ✓ Includes robust and objective analysis. ✓ Has clear triggers for action. ✓ Is flexible to accommodate future surprises ✓ Is required to protect the interests of all parties.
3: Risk posed by Incomplete design and seaward position of hard coastal defences .
3.1 Need for extension of defence toe Mean Sea Level Potential change to hard defence toe detail to add resilience to future coastal change.
3.2 EDF indicative coastal defences
3.4 EDF before / after images
3.5 Position of rock toe at BLF Approximate Seaward position of current EDF defence toe at BLF
3.6 Proximity of rock toe to beach
3.7 Reasons to move hard defence landward ➢ Defence is closer to active beach at BLF than EDF suggest. ➢ Defence toe may move further seaward in final design. ➢ Long term effects on Coastal Processes of defence exposure may be difficult to mitigate.
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