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NEECA2 TOOLBOX TALK

NEECA2 TOOLBOX TALK

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NEECA2 TOOLBOX TALK

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  1. NEECA2 TOOLBOX TALK Coastal Engineering Alex Schofield 1 Slide No.

  2. Contents • The Felixstowe Project(s) • Coastal Processes • Feasibility Study and PAR • Detailed Design • Construction • B&V Maritime and Coastal Team 2 Slide No. B&V - 2

  3. Felixstowe Projects • Started in early 2004 • Coastal Processes Study • Feasibility Study and PAR (PAR submitted Nov 2005) • Detailed Design (contract docs issued May 2006) • Strategy Review and Update (StAR submitted Aug 2007) • PAR update (PAR submitted September 2007) • Detailed Design review (contract docs issued Nov 2007) • Construction (commenced March 2008) 3 Slide No. B&V - 3

  4. Introduction to Felixstowe - where is it? 4 Slide No. B&V - 4

  5. Introduction to Felixstowe – study area Port of Felixstowe 960 residential & 468 commercial properties War Memorial to Landguard Common Landguard Fort SM Landguard Common SSSI 5 Slide No. B&V - 5

  6. Introduction to Felixstowe – Study Frontage Suffolk Coastal District Council (Coastal Protection Act) Environment Agency (Land Drainage Act) 6 Slide No. B&V - 6

  7. Introduction to Felixstowe – Existing Defences 7 Slide No. B&V - 7

  8. Introduction to Felixstowe – Existing Defences 8 Slide No. B&V - 8

  9. Coastal Processes – Wave and Water Level Conditions • Collected Wave and Water level data • Wave and water level extremes • Wave roses • Joint probability 9 Slide No. B&V - 9

  10. Coastal Processes – Wave Modelling 10 Slide No. B&V - 10

  11. Coastal Processes – Sediment Transport • Beach sampling • Equilibrium bay shape development • Potential sediment transport • Analysis of beach profile information 11 Slide No. B&V - 11

  12. Coastal Processes – Modelling • Longshore sediment movement • Cross shore sediment movement 12 Slide No. B&V - 12

  13. Coastal Processes – Modelling • Alongshore sediment transport • Cross-shore sediment movement • Tidal currents Inshore eddy Ebb Flood Net movement South Net movement North Strong cross-shore movements 13 Slide No. B&V - 13

  14. Review Data Collection and Analysis Consultation & liaison (internal and external) Identify Options Technical, Economic and Environmental Appraisal Identify Preferred Option Feasibility Study – Options Process 14 Slide No. B&V - 14

  15. Feasibility Study – Options • Beach recharge required to protect front line defences • Shoreline control structures required to hold the beach in place. Options considered: • Timber groynes (30m long @ 30m spacing) • Straight rock groynes (50m long @ 100m spacing) • Rock fishtail (‘T’ head) groynes (40m long with 20m ‘T’ @ 110m spacing) • Open beach, rock revetment, offshore reefs and large fishtail structures ruled out early on. 15 Slide No. B&V - 15

  16. Original shoreline Local accretion Local erosion Original shoreline Stable bay Feasibility Study – Technical Appraisal • Straight groynes • Fishtail groynes 16 Slide No. B&V - 16

  17. Feasibility Study – Economic Appraisal • Option capital costs costed by Team Van Oord • Strategic Business case, including risk to life damages • High economic justification (BCR = 29, PS = 27) • Economically preferred option = Rock fishtail groynes 17 Slide No. B&V - 17

  18. Feasibility Study – Consultation / Environmental Issues • SSSI (vegetated shingle) – no change to coastal processes • Change in landscape – impact on amenity and tourism 18 Slide No. B&V - 18

  19. Feasibility Study – PAR • Project Appraisal Report (PAR) presented to EA’s National Review Group in September 2007 • Approval sum of £12.4 million • Recommended for approval by NRG in November 2007, with Director of Operations approval February 2008 (following approval of strategy) 19 Slide No. B&V - 19

  20. Detailed design – Scheme Layout 20 Slide No. B&V - 20

  21. Detailed design – Rock Groynes • 3 – 6t armourstone • Bedstone below low water and geotextile above 21 Slide No. B&V - 21

  22. Detailed design – Beach Recharge • Design beach profile to bring beach levels close to promenade, with 10m berm and slope 1 in 7 • 250,000m3 beach recharge • Grading required to match existing beach material, so screening required • Pump distance 2.1km due to bathymetry of nearshore area • Beach recharge ahead of groyne construction to improve buildability 22 Slide No. B&V - 22

  23. Construction • Contract awarded Feb 2008 • Construction value £10.5m • Mobillisation commenced 1st March • Original programme completion mid August • Revised programme end of September • Construction team: • Contractor: Team Van Oord • Designer and Site Supervision: B&V • ECC PM: Haskoning 23 Slide No. B&V - 23

  24. Construction – Rock Delivery 24 Slide No. B&V - 24

  25. Construction – Groyne Construction 25 Slide No. B&V - 25

  26. Construction – Groyne Construction 26 Slide No. B&V - 26

  27. Construction – Groyne Construction 27 Slide No. B&V - 27

  28. Construction – Beach Recharge 28 Slide No. B&V - 28

  29. Construction 29 Slide No. B&V - 29

  30. Construction – So far… • Beach recharge complete • Completed approx half of the rock works • Issues encountered: • Delayed beach recharge • Bomb… • Contractor’s cost overrun • Form G required • B&V praised for our performance 30 Slide No. B&V - 30

  31. Maritime and Coastal Team • Redhill: • Norman Cox – Maritime Engineer • David Keiller – Tidal and estuary dynamics • Alex Schofield – Coastal engineering (strategy to contruction) • Peter La Roche – Coastal modelling • Lisa Hardwick, Dan Glasson, Leah Barker – Coastal engineering and site supervision • Juliette Horsford – Oceanography • Plymouth: • Paul Westaway – Maritime structures • Andrea Northey – Coastal / maritime engineering • Chester: • Andy Jones, David Barton, Alex Devine – Coastal / maritime engineering • Sub consultant: • Noel Beech – Coastal processes specialist (formerly of Haskoning) 31 Slide No. B&V - 31