HomeMy Public PortalAbout20140619DunePresentationDunes
Mike Wutkowski
Coastal Engineer
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DUNES
BENEFITS
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* The areas with existing wide beaches and a frontal dune system, either natural or man-made, experienced less storm damage.
Protected Area
Unprotected Area
North Topsail Beach
After Fran
Wrightsville Beach
After Fran
* “Hurricane Fran Effects on Communities With and Without Shore Protection: A Case Study at Six North Carolina Beaches” Dec 2000
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There are the places that had a protective dune system installed and, as a result, sustained minimal damage. Then there are the areas where there were no tall dunes, where Sandy made
its destructive powers known.
Ryan Hutchins and Seth Augenstein/The Star-Ledger
Hurricane Sandy /Long Beach Island
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Structures Threatened or Destroyed
HURRICANES FLOYD & DENNIS
Outside Projects
Inside Projects
968
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Source
Spencer Rogers North Carolina Sea Grant
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Economic Summary
Compare Recommended/Locally Preferred Plan to NED Plan
50-yr period of analysis @ 4-7/8%, Price Level October 2007
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Differences in Risk – NED and LP Plan
(one random 50-year scenario out of 1,000 in analysis)
…all 50 years
…worst event in that 50 years ( ~85-yr event )
Number of structures impacted -- most impacts are from a ______________________single, rare event
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Construction / Cost
Rule of Thumb Costs
Dune 8’ above Berm
105 ‘ wide ~20 cyds
If space exists, at $8.50/cyd ~ $170/ft
If shoreline must be
pushed seaward,
~125 cyds at $8.50/cyd
~$1,100/ft
Planting
~$8,000/acre
~$20/ft.
Doesn’t include berm or overfill.
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Crossovers
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QUESTIONS?
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