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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 M.S. Ocean Engineering January, 2006 johnhearin@yahoo.com
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
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
Wave Quality Factors • Peel Angle • Breaking Intensity
Wave Breaking Intensity (Mead, 2003)
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
Cocoa Beach Reef Site Selection Brevard County Public Beach Parks • Sheppard Park • Lori Wilson Park
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)
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)
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°
Reef Analysis Results • Average ride length ≈ 415 ft • Average ride duration ≈ 42 s • Beach break duration < 10 s • 400% increase in ride duration
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
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
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
Reef Construction Materials • Sand-Filled Containers • Geosynthetic Materials • Multi-celled modular design
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
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
Reef Deployment (ASR,2004)
Artificial Reef Benefits • Shoreline Stabilization and Erosion Protection • Ecological • Economic
Brevard County Erosion Processes • Longshore Current • Natural flow is North to South • Port Canaveral Jetties inhibit natural flow