COASTAL SHORELINE PROTECTION
USING HARD STRUCTURES
Robert W. Fairbanks, P.E., President
Fairbanks Engineering Corp.
Richar...
TYPES OF SHORELINE PROTECTION
STRUCTURES
• NON STRUCTURAL PROTECTION
• SEAWALLS
• REVETMENT
• BREAKWATERS
• GROINS
EXAMPLES OF MANMADE
CHANGES TO THE SHORELINE IN
RHODE ISLAND
USING SEAWALLS, REVETMENTS,
BREAKWATERS AND GROINS
Quonset Point War Effort
Quonset Point 1939
Before World War II

Quonset Point Today
Allen Harbor, North Kingstown
Allen Harbor Pre World
War II Effort

Allen Harbor Today
Quonochontaug Breachway
• 1952 Before State of RI
Constructed Breachway

• 1981 Aerial showing
Breachway Constructed
in 19...
Quonochontaug Pond
• Quonochontaug Today with No Maintenance
Buttonwoods Warwick, RI
• 1962 Timber and Stone
Groins Showing Sand
Accretion

• Timber Groins Not
Maintained Showing
Loss...
Buttonwoods, Warwick RI
Section Where Stone Groins Remain
Non Structural Shoreline Protection
Vegetated Beach Dune – Portsmouth, RI
Vegetated Shoreline
• Portsmouth, Rhode Island
Portsmouth Shoreline Before

Concrete
Curbs
Jamestown, Rhode Island
Coir Logs
Middletown, Rhode Island
Coir Logs on Rocky Shoreline
SEAWALLS
Steel Sheetpile Bulkhead, Road Town, BVI
Sheet Pile Dead Men Installation
Road Town, Tortola, BVI
Concrete Seawall, Hampton Beach, NH
Salisbury Beach, Massachusetts

Pre-Cast Concrete Seawall Units
Salisbury Beach, Massachusetts

Precast Concrete Units
Re-Entrant Face Seawall, San Francisco
Concrete Seawall, Westerly, RI
Timber Seawall – Portsmouth, RI
Steel Sheet Piles, Quonset Airport
REVETMENTS
• Stone placed on an earth slope, Warwick, RI
Revetment Under Construction, Jamestown, RI
Larger Revetment, Portsmouth, RI
Revetment Above Seawall, Westerly, RI
Revetment Above Seawall, Westerly, RI
STONE BREAKWATERS
SAUNDERSTOWN YACHT CLUB
Location of Former North Kingstown
To Jamestown Ferry Landing – circa 1900
Shoreline Adjacent to SYC Breakwater
North of Breakwater
High Energy as Shown by Rocky Shore

South of Breakwater
High Ene...
Beach Formed On South Side of SYC Breakwater

Breakwater Acting As a Groin, Trapping Sand
GROINS
Purpose is to trap sand to create a beach

Buttonwoods,
Warwick, RI
Remnants of Groins in Buttonwoods
Typical Groins Along Lake Michigan
Groins Typically Interrupt & Trap Sand Moving Down the Coast Replenishing
Beaches but S...
SHORELINE PROTECTION
• These structures have a place
• Many coastal shoreline areas have been protected
adequately by thes...
Non Structural Measures Pros:
Environmentally Friendly
Relatively Inexpensive to Construct and Maintain if Vegetative
B...
Seawalls Pros:
Can Provide Deep Water Adjacent to Quay Walls, Ports Piers
Small Footprint Seaward, Providing Additional ...
Breakwater Pros:
Provides Excellent Energy Absorption with Little Wave Reflection
Durable If Properly Designed With Adeq...
DESIGN PARAMETERS
• 100 Year (1%) Storm Generated Forces (FEMA)
– Wave Height
– Current Velocity
– Debris Loads

• Water D...
DESIGN WAVE HEIGHT
• FEMA Flood Study & FIRM MAP
• Case By Case Study Considering Unobstructed
Fetch (Partially or Fully D...
DESIGN WAVE HEIGHT
• Significant Wave Height, Hs
– Hs = (Max Wave Crest El – SWL) /0.7
• Example for Max Wave Crest El = 1...
EFFECT OF WAVE HEIGHT
• Forces on vertical walls1
– 4 ft wave = 8000 lbs/lf
– 8 ft wave = 16,000 lbs/lf
– 12 ft wave = 24,...
EFFECT OF WAVE HEIGHT
• Forces & increased wave height at vertical walls
EFFECT OF WAVE HEIGHT
• Revetment stone size2
– W = (Wr)(H3)/Kd(Sr – 1)3 (Cotan >)
• Stone size required for 1.5H: 1.0V sl...
EFFECT OF WAVE HEIGHT
• Typical breakwater section2

2 – US Army Corps of Engineers, Shore Protection Manual, 1984
RI SHORELINE PROJECTS
• Block Island’s Old Harbor Sheetpile Bulkhead
– PZC-34 steel sheets; 41 ft long
– Bulkhead length i...
RI SHORELINE PROJECTS
• Matunuck Beach Road Bulkhead & Revetment,
South Kingstown
– 202 lf of PZ-35 steel sheetpile (45 ft...
CARRIBEAN SHORELINE PROJECTS
• Tender Pier Anchored Bulkhead
Road Town, Tortola, BVI
– 331 lf of PZ-27 Steel Sheetpile (36...
RI SHORELINE PROJECTS
• Larkin Road Seawall, Watch Hill
– 185 lf of Concrete Seawall (17 ft high)
– 18” -30” thick stem & ...
RI SHORELINE PROJECTS
• Whipple Ave Revetment, Warwick
– 100 lf of stone revetment
– 5000 to 8000 lb stone, 2 stone armor ...
RI SHORELINE PROJECTS
• 75 Surfside Ave, Charlestown
– 150 lf of stone revetment
– 12000 lb stone, 2 stone armor layer
– C...
RI SHORELINE PROJECTS
• 89 Surfside Ave, Charlestown
– 70 lf of stone revetment
– 12000 lb stone, 2 stone armor layer
– Co...
RI SHORELINE PROJECTS
• Baker Road, Portsmouth
– 90 lf of stone revetment
– 8000 lb stone, 2 stone armor layer
– Estimated...
RI SHORELINE PROJECTS
• Watch Hill Lighthouse Revetment, Watch Hill
– 1,700 lf+- of existing stone revetment repairs
– 20,...
RI SHORELINE PROJECTS
• Larkin Ave Groin, Watch Hill
– 150 lf+- of existing stone groin repairs
– 3,000 to 4,000 lb stones...
CARRIBEAN SHORELINE PROJECTS
• Tender & Ferry Pier Breakwater
Road Town, Tortola, BVI
– 200 lf stone breakwater
– 6,000 to...
Examples of Programs Used for Design
When Things Go Wrong
Westerly Town Property After
Tropical Storm Sandy
Building was Demolished After Storm
House in Charlestown

Damage caused by hurricane Sandy
House in Anegada, BVI

One of several cottages damaged due to
severe shoreline erosion
Jamestown, Rhode Island

Shoreline Protection Is Currently Under Re-Construction
Erosion @ Coast Guard House,
Narragansett, RI
Forces Under Piers/Bridge Decks
Bridge Across Escambia Bay, Florida
Hurricane Ivan 9/16/2004
Biloxi Bay Bridge, Mississippi
Hurricane Katrina
U.S. 90 Biloxi Bay Bridge
Hurricane Katrina
SUMMARY
• Design is complex & requires several design
parameters
–
–
–
–
–
–
–
–
–
–

Wave height for design
Storm flood d...
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Robert W. Fairbanks and Richard N. St. Jean, Coastal Shoreline Protection Using Hard Structures

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BeachSAMP Stakeholder Meeting
December 9th, 2013
Robert W. Fairbanks, P.E., President
Fairbanks Engineering Corp.
Richard N. St. Jean, P.E., President
St. Jean Engineering, LLC

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Robert W. Fairbanks and Richard N. St. Jean, Coastal Shoreline Protection Using Hard Structures

  1. 1. COASTAL SHORELINE PROTECTION USING HARD STRUCTURES Robert W. Fairbanks, P.E., President Fairbanks Engineering Corp. Richard N. St. Jean, P.E., President St. Jean Engineering, LLC
  2. 2. TYPES OF SHORELINE PROTECTION STRUCTURES • NON STRUCTURAL PROTECTION • SEAWALLS • REVETMENT • BREAKWATERS • GROINS
  3. 3. EXAMPLES OF MANMADE CHANGES TO THE SHORELINE IN RHODE ISLAND USING SEAWALLS, REVETMENTS, BREAKWATERS AND GROINS
  4. 4. Quonset Point War Effort Quonset Point 1939 Before World War II Quonset Point Today
  5. 5. Allen Harbor, North Kingstown Allen Harbor Pre World War II Effort Allen Harbor Today
  6. 6. Quonochontaug Breachway • 1952 Before State of RI Constructed Breachway • 1981 Aerial showing Breachway Constructed in 1962, and Sediment Entering Pond
  7. 7. Quonochontaug Pond • Quonochontaug Today with No Maintenance
  8. 8. Buttonwoods Warwick, RI • 1962 Timber and Stone Groins Showing Sand Accretion • Timber Groins Not Maintained Showing Loss of Accreted Sand
  9. 9. Buttonwoods, Warwick RI Section Where Stone Groins Remain
  10. 10. Non Structural Shoreline Protection Vegetated Beach Dune – Portsmouth, RI
  11. 11. Vegetated Shoreline • Portsmouth, Rhode Island
  12. 12. Portsmouth Shoreline Before Concrete Curbs
  13. 13. Jamestown, Rhode Island Coir Logs
  14. 14. Middletown, Rhode Island Coir Logs on Rocky Shoreline
  15. 15. SEAWALLS Steel Sheetpile Bulkhead, Road Town, BVI
  16. 16. Sheet Pile Dead Men Installation Road Town, Tortola, BVI
  17. 17. Concrete Seawall, Hampton Beach, NH
  18. 18. Salisbury Beach, Massachusetts Pre-Cast Concrete Seawall Units
  19. 19. Salisbury Beach, Massachusetts Precast Concrete Units
  20. 20. Re-Entrant Face Seawall, San Francisco
  21. 21. Concrete Seawall, Westerly, RI
  22. 22. Timber Seawall – Portsmouth, RI
  23. 23. Steel Sheet Piles, Quonset Airport
  24. 24. REVETMENTS • Stone placed on an earth slope, Warwick, RI
  25. 25. Revetment Under Construction, Jamestown, RI
  26. 26. Larger Revetment, Portsmouth, RI
  27. 27. Revetment Above Seawall, Westerly, RI
  28. 28. Revetment Above Seawall, Westerly, RI
  29. 29. STONE BREAKWATERS SAUNDERSTOWN YACHT CLUB Location of Former North Kingstown To Jamestown Ferry Landing – circa 1900
  30. 30. Shoreline Adjacent to SYC Breakwater North of Breakwater High Energy as Shown by Rocky Shore South of Breakwater High Energy as Shown by Rocky Shore
  31. 31. Beach Formed On South Side of SYC Breakwater Breakwater Acting As a Groin, Trapping Sand
  32. 32. GROINS Purpose is to trap sand to create a beach Buttonwoods, Warwick, RI
  33. 33. Remnants of Groins in Buttonwoods
  34. 34. Typical Groins Along Lake Michigan Groins Typically Interrupt & Trap Sand Moving Down the Coast Replenishing Beaches but Starve Down Shore Beaches Leading to More Aggressive Erosion. Tee Type Groin Standard Groin
  35. 35. SHORELINE PROTECTION • These structures have a place • Many coastal shoreline areas have been protected adequately by these structures across the country • Ports require deep water at dock faces • Ports require protection from waves to allow cargo to be loaded and unloaded • Municipalities need to protect infrastructure • Homeowners need to protect property – However these structures typically protect the shoreline better than they protect the structures behind
  36. 36. Non Structural Measures Pros: Environmentally Friendly Relatively Inexpensive to Construct and Maintain if Vegetative Blends into Natural Shoreline and Provides Essential Habitat Typically Does not Cause Erosion of Adjacent Properties Preferred Method in Low Energy Locations (Coves, Protected Areas) Easy to Permit Non Structural Measures Cons: Ineffective for Large Fetch Areas Where Waves are in Excess of Approx. 2 Feet Required Frequent Maintenance After Storm Events Requires a Large Footprint Perpendicular to the Shore
  37. 37. Seawalls Pros: Can Provide Deep Water Adjacent to Quay Walls, Ports Piers Small Footprint Seaward, Providing Additional Room for Navigation Excellent Earth Retention with Little to No Loss of Soil Behind Wall When Maintained When Properly Designed Can Sustain High Surcharge Loads at Piers and Adjacent Railways Can Incorporate Cleats, Bollards and Mooring Bits for Docking Seawall Cons: Large Wave Reflection Which Can Almost Double the Incoming Wave Height If Wave Phases Line Up Causing Damage to Marina Facilities Can Cause Excessive Erosion At Beginning and Ends of Wall Costly to Construct Short Life if not Properly Maintained (30 to 50 years) Possibly Shorter Life if in a Marina Environment Due to Stray Electric Current Permitted in Only Certain Water Types
  38. 38. Breakwater Pros: Provides Excellent Energy Absorption with Little Wave Reflection Durable If Properly Designed With Adequate Stone Sizes & Geometry Provides Fish and Sea Creature Habitat Long Lasting if Properly Designed with Durable Stones Ideal for Creating a Refuge Area for Port Facilities and Quiet Water for Pier Operations Breakwater Cons: Very Costly to Construct and Maintain Upsets Natural Circulation and Sediment Patterns Possibly for Long Distances Covers a Large Footprint at the Mud Line Requires Frequent Dredging At Harbor Entrances and Within Basin  Navigation Hazard if Not Properly Marked Very Difficult to Permit
  39. 39. DESIGN PARAMETERS • 100 Year (1%) Storm Generated Forces (FEMA) – Wave Height – Current Velocity – Debris Loads • Water Depth (Bathymetric Survey) • Shoreline Profile
  40. 40. DESIGN WAVE HEIGHT • FEMA Flood Study & FIRM MAP • Case By Case Study Considering Unobstructed Fetch (Partially or Fully Developed Seas) and Water Depth Approaching Structure Location Typical Design Parameters for Critical Structures – 100 yr Return (1%) Stillwater Elevation (SWL) – 100 yr Return (1%) Maximum Wave Crest Elevation (May Use a More Frequent Storm Event for Structures That Can Sustain Some Damage Without Loss of Life, Can be Readily Repaired, and Small Economic Impact)
  41. 41. DESIGN WAVE HEIGHT • Significant Wave Height, Hs – Hs = (Max Wave Crest El – SWL) /0.7 • Example for Max Wave Crest El = 12.0 ft & SWL = 9.0 ft • Hs = 12.0 ft – 9.0 ft/0.7 = 4.28 ft • Design for H10 = 1.27 Hs
  42. 42. EFFECT OF WAVE HEIGHT • Forces on vertical walls1 – 4 ft wave = 8000 lbs/lf – 8 ft wave = 16,000 lbs/lf – 12 ft wave = 24,000 lbs/lf 1 – Coastal Construction Manual, Figure 11-8
  43. 43. EFFECT OF WAVE HEIGHT • Forces & increased wave height at vertical walls
  44. 44. EFFECT OF WAVE HEIGHT • Revetment stone size2 – W = (Wr)(H3)/Kd(Sr – 1)3 (Cotan >) • Stone size required for 1.5H: 1.0V slope; 2 stone armor layer – – – – 4 ft wave = 2200 lbs (2.4 ft stone) 8 ft wave= 18,000 lbs (4.8 ft stone) 12 ft wave = 60,000 lbs (7 ft stone) 16 ft wave = 142,000 lbs (9.5 ft stone) 2 – US Army Corps of Engineers, Shore Protection Manual, 1984
  45. 45. EFFECT OF WAVE HEIGHT • Typical breakwater section2 2 – US Army Corps of Engineers, Shore Protection Manual, 1984
  46. 46. RI SHORELINE PROJECTS • Block Island’s Old Harbor Sheetpile Bulkhead – PZC-34 steel sheets; 41 ft long – Bulkhead length is 242 lf – Cost $732,000 or $3,025/lf
  47. 47. RI SHORELINE PROJECTS • Matunuck Beach Road Bulkhead & Revetment, South Kingstown – 202 lf of PZ-35 steel sheetpile (45 ft long sheets) – 202 lf of 11 ton armor stone (2 layers) – Cost $1,000,000 or $4,950/lf
  48. 48. CARRIBEAN SHORELINE PROJECTS • Tender Pier Anchored Bulkhead Road Town, Tortola, BVI – 331 lf of PZ-27 Steel Sheetpile (36 ft long sheets) – Buried Concrete Deadman w/ Steel Tie-rods – Cost $1,200,000 or $3,625/lf
  49. 49. RI SHORELINE PROJECTS • Larkin Road Seawall, Watch Hill – 185 lf of Concrete Seawall (17 ft high) – 18” -30” thick stem & 9 ft wide footing – Cost $500,000 or $2,700/lf
  50. 50. RI SHORELINE PROJECTS • Whipple Ave Revetment, Warwick – 100 lf of stone revetment – 5000 to 8000 lb stone, 2 stone armor layer – Cost $25,000 or $250/lf
  51. 51. RI SHORELINE PROJECTS • 75 Surfside Ave, Charlestown – 150 lf of stone revetment – 12000 lb stone, 2 stone armor layer – Cost $150,000 or $1,000/lf
  52. 52. RI SHORELINE PROJECTS • 89 Surfside Ave, Charlestown – 70 lf of stone revetment – 12000 lb stone, 2 stone armor layer – Cost $93,000 or $1,330/lf
  53. 53. RI SHORELINE PROJECTS • Baker Road, Portsmouth – 90 lf of stone revetment – 8000 lb stone, 2 stone armor layer – Estimated Cost $90,000 Or $1,000/lf
  54. 54. RI SHORELINE PROJECTS • Watch Hill Lighthouse Revetment, Watch Hill – 1,700 lf+- of existing stone revetment repairs – 20,000 lb stones or larger – 22 ft design wave heights – Estimated Cost N/A
  55. 55. RI SHORELINE PROJECTS • Larkin Ave Groin, Watch Hill – 150 lf+- of existing stone groin repairs – 3,000 to 4,000 lb stones – Estimated Cost $25,000+- or $170+-/lf
  56. 56. CARRIBEAN SHORELINE PROJECTS • Tender & Ferry Pier Breakwater Road Town, Tortola, BVI – 200 lf stone breakwater – 6,000 to 8,000 lb stones (2 stone armor layer) – Estimated Cost $620,000 or $3,100/lf
  57. 57. Examples of Programs Used for Design
  58. 58. When Things Go Wrong Westerly Town Property After Tropical Storm Sandy Building was Demolished After Storm
  59. 59. House in Charlestown Damage caused by hurricane Sandy
  60. 60. House in Anegada, BVI One of several cottages damaged due to severe shoreline erosion
  61. 61. Jamestown, Rhode Island Shoreline Protection Is Currently Under Re-Construction
  62. 62. Erosion @ Coast Guard House, Narragansett, RI
  63. 63. Forces Under Piers/Bridge Decks
  64. 64. Bridge Across Escambia Bay, Florida Hurricane Ivan 9/16/2004
  65. 65. Biloxi Bay Bridge, Mississippi Hurricane Katrina
  66. 66. U.S. 90 Biloxi Bay Bridge Hurricane Katrina
  67. 67. SUMMARY • Design is complex & requires several design parameters – – – – – – – – – – Wave height for design Storm flood depth (SWL) Water depth (bathymetry) Affect on littoral transport End effects Structure use Can structure sustain damage Permit ability Constructability Cost

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