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Beach Nourishment Project
Town of Kitty Hawk, North Carolina
Coastal Planning & Engineering of North Carolina
November 3, 2014
Ken Willson
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Project Overview Map
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Kitty Hawk Project Area
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Kitty Hawk Stated Purpose:
1. Reduce the vulnerability of public infrastructure including NC 12, town roads between NC 12 and U.S. Highway 158, and utilities to storm-induced erosion;
2. Reduce flooding experienced in many non-oceanfront areas throughout the Town during ocean over wash conditions, including portions of NC Highway 12 and U.S. Highway 158; and
3. Reduce the vulnerability of homes within the Town that front the Atlantic Ocean and are exposed to wave events during nor’easters and other large storm events as well as natural trends.
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Storm Damage Reduction to Infrastructure
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Flood Damage Reduction to Non-Oceanfront Areas
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Storm Damage Reduction to Oceanfront Homes
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Storm Damage Reduction Project
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Dune
Design Beach
Berm Width6.0 ft.
NAVD88
Storm Damage Reduction Project Example
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Constructed Beach Fill
Storm Damage Reduction Project Example
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Post-ConstructionAdjustment in 1-3 years
Storm Damage Reduction Project Example
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Advance Fill
Design Beach
Storm Damage Reduction Project Example
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Dune
Loss of Advance Fill In 5-10 years
Design Beach
Berm Width6.0 ft.
NAVD88
Storm Damage Reduction Project Example
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When structures are seaward of the dune, more sand is required toconstruct the design seaward of the structures.
Storm Damage Reduction Project Example
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When structures are seaward of the dune, more sand is required toconstruct the design seaward of the structures.
Built in front of structures
Berm Width6.0 ft.
NAVD88
Dune
+13.0 ft.
Design Beach
Storm Damage Reduction Project Example
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Design Beach
When structures are seaward of the dune, more sand is required toconstruct the design seaward of the structures.
Tie into existing dune
Berm Width6.0 ft.
NAVD88
Dune
+13.0 ft.
Storm Damage Reduction Project Example
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ALTERNATIVE VOLUME (CY) DENSITY (CY/FT)
ALTERNATIVE 1 – Dune and Berm Design (20 ft. wide, 13 ft. high dune; 50 ft. wide, 6 ft. high berm (Tie into Existing Dune)
1,583,000 81.3
ALTERNATIVE 2 – Dune and Berm Design (20 ft. wide, 13 ft. high dune; 50 ft. wide, 6 ft. high berm (Seaward of Structures)
2,872,000 147.4
81% Increase
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Berm Only Option
50’ Berm Width6.0 ft.
NAVD88
Design Beach
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Minimal Dune Design - 12
30’ Berm Width6.0 ft.
NAVD8810’ Dune
Width+12.0 ft.
Design Beach
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Storm Damage Reduction Analysis
• Minimal simulated impact to the road given existing conditions
• No impacts to the road with berm only or MDD-12 design.
1. Reduce the vulnerability of public infrastructure including NC 12, town roads between NC 12 and U.S. Highway 158, and utilities to storm-induced erosion;
• 122 structures impacted given existing conditions. 48% reduction with berm only and 64% reduction with MDD-12 design
3. Reduce the vulnerability of homes within the Town that front the Atlantic Ocean and are exposed to wave events during nor’easters and other large storm events as well as natural trends;
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Runup Evaluation
Calculated Runup Elevation
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Runup Evaluation
Calculated Runup Elevation
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Runup Evaluation
Runup Elevation
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Design Beach
Calculated Runup Elevation
With ProjectWithout Project
Design Beach
Runup Evaluation
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Design BeachDesign
Beach
Design Beach
Calculated Runup Elevation
With ProjectWithout Project
Design Beach
Runup Evaluation
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Design BeachDesign
Beach
Design Beach
Calculated Runup Elevation
With ProjectWithout Project
Design Beach
Runup Evaluation
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Runup Evaluation
Runup Elevation = Lower Than Elevation of the Road
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Annual Event Runup Analysis
• 12 ft. Dune Design and 50 Ft. Berm:
– 69.8% to 92.7 % reduction in length of shoreline exceeded by calculated runup.
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5 – Year Event• “Kill Devil Hills” Design – 15 ft. high / 20 ft. wide dune, fronted
by a 40 ft. berm
– Advances Shoreline 100 ft. (Average)
– Requires 3.19 Million CY
– 100% increase in Volume
– Additional $15 Million
• 100 – Ft. Berm Only Design
– Advances Shoreline 100 ft.
– Requires 2.93 Million CY
– 84% increase in Volume
– Additional $12.5 Million
• What could we do with another $2 Million - $3 Million
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5 – Year Event
• $ 3 Million = ~ 16 CY/Ft. More Sand
• Design: Slightly Over a 60 ft. Design Berm
– Annual Event - 73.4% to 98.7 % reduction in length of shoreline exceeded by calculated runup.
– 5-Year Event – 39.6% to 72.2% reduction in length of shoreline exceeded by calculated runup.
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Runup Elevation
Runup Evaluation
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5 – Year Event
• $ 3 Million = ~ 16 CY/Ft. More Sand
• Design: Slightly Over a 60 ft. Design Berm
– Annual Event - 73.4% to 98.7 % reduction in length of shoreline exceeded by calculated runup.
– 5-Year Event – 39.6% to 72.2% reduction in length of shoreline exceeded by calculated runup.
– With 14.0 ft. NAVD Starter Dune these numbers become 100%
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60 Ft. Berm Design
• 60 Ft. Berm; 14.0 ft. NAVD “Starter Dune”; Sand Fencing
• Main Fill Length – 18,900 ft. (3.58 miles)
• 1000 Ft. Taper on North End
• Fill Density ~ 95 cy/ft. to ~100 cy/ft.
• Total Volume = ~1.91 Million Cubic Yards
• Project Cost = ~$20.5 Million
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Task Name Projected Completion
Compatibility Analysis 10/24/2014
Kitty Hawk Design Finalized 11/3/2014
Address USACE and BOEM Comments and release EFH and BA 10/28/2014
Completion of USACE, BOEM, USFWS, and NMFS Consultation 10/28/2015
Address Comments and Release Draft EA (Duck, KH, and KDH) 11/14/2014
Submit CAMA Applications February/March 2015
BOEM Lease Agreement Issued 1/1/2016
Open Bids Anytime After 1/1/2016
Construction Beginning March 2016
Schedule
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Beach Nourishment Project
Town of Kitty Hawk, North Carolina
Questions??
Ken Willson – [email protected]
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Kill Devil Hills Project Area
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Duck Project Area
