SEA--LEVEL RISE ADAPTATION
SEA
in Coastal NC (in human terms)
HAZARD--RESILIENT
HAZARD
COMMUNITIES
Spencer Rogers
North Carolina Sea Grant
UNC--Wilmington Center for Marine Science
UNC
NCSU Dept. of Civil Engineering
SEA-LEVEL RISE
• Education
Understand the risk &
consequences
What to expect
• Adaptation
D something
Do
thi
SEA LEVEL RISE
SEA-LEVEL
ADAPTATION
BARRIERS:
• Imperceptible
I
tibl Rate
R t off Change
Ch
• Distant Consequences in Time
• Uncertain Science
•
Debate not pretty
SCIENCE PANEL ON COASTAL HAZARDS
SEA-LEVEL RISE
PLANNING RECOMMENDATION
2010 SEA LEVEL
RECENT HISTORICAL PROJECTION
PANEL PLANNING RECOMMENDATION
HIGHER POSSIBLE ACCELERATION
1 meter
HIGH TIDE
2010
SEA LEVEL
30 YEARS
LOW TIDE
CRC Science Panel 2015 SLR Update
NC Tide Gauge Data
http://tidesandcurrents.noaa.gov/sltrends/sltrends.html
CRC Science Panel 2015 SLR Update
Vertical Land Movement*
Approximate
location of NOAA
tide gauges
*Values calculated by Zervas using methods described in Zervas, C., Gill, S.,
and W. Sweet. 2013. NOS Technical Report NOS CO-OPS 065. Estimating
Vertical Land Motion from Long-Term Tide Gauge Records and updated
through December 2013.
TIDE GAGE
MEASURED RISE
IN SEA LEVEL
CRC Science Panel 2015 SLR Update
IPCC Representative Concentration Pathways*
~1 yard
30
YEARS
*modified from Table AII.7.7, Intergovernmental Panel on Climate Change (IPCC), 2013a. Annex II: Climate System Scenario Tables
SEA-LEVEL RISE
What to expect?
p
• More frequent, shallow water,
nuisance flooding
• Higher extreme flood events
SEA-LEVEL RISE
ADAPTATION
Don
Don’tt Get Wet
• NC State Building
g Code
2nd Oldest Hurricane Building
Code in U
U.S.
S 1960s
• National Flood Insurance
Program ~1970s
SEA-LEVEL RISE
ADAPTATION
FREEBOARD
100-YEAR FLOOD or
1% CHANCE EACH YEAR
NO SAFETY FACTORS
ACCUMULATED RISK
100 Year Flood = 1% Risk Each
100-Year
Year
• 70
70-Year
Year Average Building Lifetime
= 51% RISK OF EXCEEDANCE
HEADS or TAILS!
SEA-LEVEL RISE
ADAPTATION
FREEBOARD INCENTIVES
COMMUNITY RATING SYSTEM
• Improve Flood Hazard Awareness
• Improve Preparedness
• Reduce Future Damage
~1% Discount for each foot of freeboard
44% of Coastal Communities in CRS
Topsail B = 25% CRS DISCOUNTS
CB & WB = 15%
NHC & KB = 10%
SEA-LEVEL RISE
ADAPTATION
FREEBOARD INCENTIVES
112 Coastal Communities
• 3 feet
4%
• >2 feet 47%
• >1 foot 81% (92% POPULATION)
March 1,, 2012 statewide
NC State Building Code*
FREEBOARD = 2 FEET
NHC, Wilm & WB
2010
SEA LEVEL
~66 YEARS
SEA-LEVEL RISE
ADAPTATION
FREEBOARD INCENTIVES
NFIP elevation discounts
V-zone: $250K building/$100K contents
• +4 feet 70% DISCOUNT ($6010/year)
• +3 feet
67% DISCOUNT
• +2 feet
63% DISCOUNT
• +1 foot
49% DISCOUNT
• Minimum $8608 Annual Premium
SEA-LEVEL RISE
ADAPTATION
EROSION RATES
CAMA Oceanfront Erosion Rate
Setback Lines 1979
SEA LEVEL RISE
SEA-LEVEL
ADAPTATION
What action needs to be taken?
What are the most compelling
p
g reasons
to take the action?
SEA-LEVEL RISE
What to expect?
p
• More frequent, low elevation,
nuisance flooding
• Higher extreme flood events
SEA-LEVEL RISE
ADAPTATION
HAZARD RESILIENT
HAZARDCOMMUNITIES
• Present not FUTURE CONDITIONS
• What If Sea Level Does Not Rise?
• Historical Hazards
The Third Annual Storm of the Century
Do it like Ike!
HURRICANE
IKE
1938
SEA LEVEL RISE ADAPTATION:
SEA-LEVEL
ADAPTATION
Lessons from a
Used-Car Salesman
1938
TOPSAIL ISLAND
SHORELINE & BEACHFILL
EXPECTATIONS
SPENCER ROGERS
NC Sea Grant
CENTER FOR MARINE SCIENCE
UNC--Wilmington
UNC
CIVIL ENGINEERING
NC State University
SEA-LEVEL RISE ADAPTATION in
SEACoastal NC (in human terms)
HAZARD--RESILIENT COMMUNITIES
HAZARD
1938
TARGET YOUR AUDIENCE
FREEBOARD = 1 FOOT
Topsail B & Oak Island
2010
SEA LEVEL
~41 YEARS
CRC Science Panel 2015 SLR Update
NC Tide Gauge Data
http://tidesandcurrents.noaa.gov/sltrends/sltrends.html
CRC Science Panel 2015 SLR Update
IPCC RCP Scenarios + VLM
Station
IPCC RCP 2
2.6
6 + VLM
IPCC RCP 8
8.5
5 + VLM
RSLR in 30 years (inches)
RSLR in 30 years (inches)
Mean
Range
Mean
Range
Duck
7.1
4.8 - 9.4
8.1
5.5 - 10.6
Oregon Inlet
6.3
3.9 - 8.7
7.3
4.7 - 9.9
Beaufort
6.5
4.2 - 8.7
7.5
5.0 - 10.0
Wilmington
5.8
3.5 - 8.0
6.8
4.3 - 9.3
Southport
5.9
3.7 - 8.2
6.9
4.4 - 9.4
*Note: Projections w ere rounded to the nearest tenth of an inch.
CRC Science Panel 2015 SLR Update
NC Tide Gauge Data
http://tidesandcurrents.noaa.gov/sltrends/sltrends.html
SEA-LEVEL RISE
ADAPTATION
EROSION RATES
CAMA Oceanfront Erosion Rate
Setback Lines 1979
SCIENCE PANEL ON COASTAL HAZARDS
SEA-LEVEL RISE
PLANNING RECOMMENDATION
2010 SEA LEVEL
RECENT HISTORICAL PROJECTION
PANEL PLANNING RECOMMENDATION
HIGHER POSSIBLE ACCELERATION
1 meter
HIGH TIDE
~8 INCHES
2010
SEA LEVEL
30 YEARS
LOW TIDE