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Preliminary Design of an Artificial Surfing Reef for Cocoa Beach, Florida by John Hearin

Preliminary Design of an Artificial Surfing Reef for Cocoa Beach, Florida by John Hearin M.S. Ocean Engineering January, 2006 johnhearin@yahoo.com. Purposes of Cocoa Beach ASR . Provide Brevard County with a world-class surfing reef break

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Preliminary Design of an Artificial Surfing Reef for Cocoa Beach, Florida by John Hearin

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  1. Preliminary Design of an Artificial Surfing Reef for Cocoa Beach, Florida by John Hearin M.S. Ocean Engineering January, 2006 johnhearin@yahoo.com

  2. Purposes of Cocoa Beach ASR • Provide Brevard County with a world-class surfing reef break • Stabilize shoreline and provide significant protection from beach erosion • Provide a stable habitat for marine life • Boost local economy

  3. Science of Surfing • Dr. James “Kimo” Walker, Univ. of Hawaii • Journal of Coastal Research, Special Issue #29, 2001 • International Surfing Reef Symposiums (3) • ASR Limited, New Zealand • Dr. Kerry Black and Dr. Shaw Mead

  4. Surfing Terminology(Hutt et al., 2001)

  5. Wave Quality Factors • Peel Angle • Breaking Intensity

  6. Wave Peel Angle (Hutt et al., 2001)

  7. Surfing Skill Levels (Hutt et al., 2001)

  8. Peel Angles for Surfing Maneuvers(Scarfe, 2002)

  9. Refraction Reduces Peel Angle

  10. Wave Breaking Intensity (Mead, 2003)

  11. Wave Breaking Intensity(Mead and Black, 2001b)

  12. Artificial Surfing Reefs (ASR) • Cables Station, Australia, 1999 • Pratt’s Reef, California, 2000 • ASR Limited of New Zealand • Gold Coast, Australia, 2000 • Mount Maunganui, New Zealand, under construction • Planning and design phase • Oil Peers, Ventura, CA • Long Branch, NJ • Palm Beach County, FL

  13. Cables Station, Australia

  14. Gold Coast ASR(ASR Ltd., 2004)

  15. Cocoa Beach Reef Site Selection Brevard County Public Beach Parks • Sheppard Park • Lori Wilson Park

  16. Sheppard Park(FDEP, 2005)

  17. Lori Wilson Park(FDEP, 2005)

  18. Tide Data

  19. Cocoa Beach Wave Data • USACE Wave Information Studies 1980-1999 • Mean Wave Conditions • Significant Wave Height = 1.2m = 3.9 ft • Peak Period = 7 s • Direction = 90° True (shore normal)

  20. Wave Height Probability

  21. Wave Period Probability

  22. Wave Direction Probability

  23. Beach and Bathymetry Surveys • Shoreline to 30 ft deep (≈ 4000 ft 0ffshore) • Kayak • GPS receiver WAAS enabled (± 10 ft) • Hand held sonar (± 1 ft) • 4 equally spaced transits at each site • Time, depth, position • Depth corrected for tide (6 min intervals)

  24. Reef Design Parameters • Wave Heights: 2 – 10 ft / Mean 3.9 ft • Wave Periods: 5 – 14 s / Mean 7s • Wave Direction: 45° - 135° / Mean 90° • Reef Orientation: shore normal (90°) • Breaking Intensity: medium – high • Peel Angle Range: 30°- 60°

  25. Wave Direction

  26. Wave Direction

  27. View looking Offshore

  28. Reef Analysis Results • Average ride length ≈ 415 ft • Average ride duration ≈ 42 s • Beach break duration < 10 s • 400% increase in ride duration

  29. Reef Analysis Results • Peel Angles: 35°- 70° • Average Peel Angle: 53° • Within desired range • Vortex Ratios: 4.2 – 1.7 • Average Vortex Ratio: 2.5 • Breaking intensities: low to extreme • Average Breaking Intensity: high • Within desired range

  30. Reef Analysis Conclusions • Should produce a broad range of peel angles and breaking intensities • Suitable for surfers at intermediate skill level and above • Average ride ≈ 415 ft / 42 s • Should break at low tide for waves > 1.7 ft

  31. Reef Analysis Conclusions • Should break at all tides for waves > 5 ft • Should produce ride-able waves 85% • Should produce good waves 45% (Hb ≥ 3ft) • Should produce high intensity tube rides during favorable wave conditions at low and mid tides

  32. Reef Construction Materials • Sand-Filled Containers • Geosynthetic Materials • Multi-celled modular design

  33. Multi-Celled Sand Filled Container during Fill Operation

  34. Geosynthetic Material • Inner Layer: polymer coated woven polyester geomembrane (impermeable) • Outer Layer: geotextile protective covering • Field tested 19 years without failure due to debris impact • 40 year design life

  35. Modular Design

  36. Reef Construction • Location surveyed using Differential GPS • Anchors and restraints installed by divers • Modules delivered on rollers • Rollers mounted to support vessel • Modules deployed empty and restrained by divers • Filled in place from hopper barges using dredge pumps

  37. Reef Deployment (ASR,2004)

  38. Cost Estimates

  39. Artificial Reef Benefits • Shoreline Stabilization and Erosion Protection • Ecological • Economic

  40. Brevard County Erosion Processes • Longshore Current • Natural flow is North to South • Port Canaveral Jetties inhibit natural flow

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