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

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. TYPES OF SHORELINE PROTECTION
STRUCTURES
• NON STRUCTURAL PROTECTION
• SEAWALLS
• REVETMENT
• BREAKWATERS
• GROINS

3. EXAMPLES OF MANMADE
CHANGES TO THE SHORELINE IN
RHODE ISLAND
USING SEAWALLS, REVETMENTS,
BREAKWATERS AND GROINS

4. Quonset Point War Effort
Quonset Point 1939
Before World War II
Quonset Point Today

5. Allen Harbor, North Kingstown
Allen Harbor Pre World
War II Effort
Allen Harbor Today

6. Quonochontaug Breachway
• 1952 Before State of RI
Constructed Breachway
• 1981 Aerial showing
Breachway Constructed
in 1962, and Sediment
Entering Pond

7. Quonochontaug Pond
• Quonochontaug Today with No Maintenance

8. Buttonwoods Warwick, RI
• 1962 Timber and Stone
Groins Showing Sand
Accretion
• Timber Groins Not
Maintained Showing
Loss of Accreted Sand

9. Buttonwoods, Warwick RI
Section Where Stone Groins Remain

10. Non Structural Shoreline Protection
Vegetated Beach Dune – Portsmouth, RI

11. Vegetated Shoreline
• Portsmouth, Rhode Island

12. Portsmouth Shoreline Before
Concrete
Curbs

13. Jamestown, Rhode Island
Coir Logs

14. Middletown, Rhode Island
Coir Logs on Rocky Shoreline

15. SEAWALLS
Steel Sheetpile Bulkhead, Road Town, BVI

16. Sheet Pile Dead Men Installation
Road Town, Tortola, BVI

17. Concrete Seawall, Hampton Beach, NH

18. Salisbury Beach, Massachusetts
Pre-Cast Concrete Seawall Units

19. Salisbury Beach, Massachusetts
Precast Concrete Units

20. Re-Entrant Face Seawall, San Francisco

21. Concrete Seawall, Westerly, RI

22. Timber Seawall – Portsmouth, RI

23. Steel Sheet Piles, Quonset Airport

24. REVETMENTS
• Stone placed on an earth slope, Warwick, RI

25. Revetment Under Construction, Jamestown, RI

26. Larger Revetment, Portsmouth, RI

27. Revetment Above Seawall, Westerly, RI

28. Revetment Above Seawall, Westerly, RI

29. STONE BREAKWATERS
SAUNDERSTOWN YACHT CLUB
Location of Former North Kingstown
To Jamestown Ferry Landing – circa 1900

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. Beach Formed On South Side of SYC Breakwater
Breakwater Acting As a Groin, Trapping Sand

32. GROINS
Purpose is to trap sand to create a beach
Buttonwoods,
Warwick, RI

33. Remnants of Groins in Buttonwoods

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. 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. 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. 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. 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. DESIGN PARAMETERS
• 100 Year (1%) Storm Generated Forces (FEMA)
– Wave Height
– Current Velocity
– Debris Loads
• Water Depth (Bathymetric Survey)
• Shoreline Profile

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. 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. 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. EFFECT OF WAVE HEIGHT
• Forces & increased wave height at vertical walls

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. EFFECT OF WAVE HEIGHT
• Typical breakwater section2
2 – US Army Corps of Engineers, Shore Protection Manual, 1984

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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. Examples of Programs Used for Design

58. When Things Go Wrong
Westerly Town Property After
Tropical Storm Sandy
Building was Demolished After Storm

59. House in Charlestown
Damage caused by hurricane Sandy

60. House in Anegada, BVI
One of several cottages damaged due to
severe shoreline erosion

61. Jamestown, Rhode Island
Shoreline Protection Is Currently Under Re-Construction

62. Erosion @ Coast Guard House,
Narragansett, RI

63. Forces Under Piers/Bridge Decks

64. Bridge Across Escambia Bay, Florida
Hurricane Ivan 9/16/2004

65. Biloxi Bay Bridge, Mississippi
Hurricane Katrina

66. U.S. 90 Biloxi Bay Bridge
Hurricane Katrina

67. SUMMARY
• Design is complex & requires several design
parameters
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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