LEVEL RISE RISE ADAPTATION

Transcription

1 SEA-LEVEL RISE ADAPTATION in Coastal NC (in human terms) HAZARD-RESILIENT RESILIENT COMMUNITIES Spencer Rogers North Carolina Sea Grant UNC-Wilmington Center for Marine Science NCSU Dept. of Civil Engineering

2 SEA-LEVEL RISE Education Understand the risk & consequences What to expect Adaptation Do something

3 SEA-LEVEL RISE ADAPTATION BARRIERS: Imperceptible Rate of Change Distant Consequences in Time Uncertain Science Debate not pretty

4 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

5 CRC Science Panel 2015 SLR Update NC Tide Gauge Data

6 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 NOS Technical Report NOS CO-OPS 065. Estimating Vertical Land Motion from Long-Term Tide Gauge Records and updated through December 2013.

7 TIDE GAGE MEASURED RISE IN SEA LEVEL

8

9 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

10 SEA-LEVEL RISE What to expect? More frequent, shallow water, nuisance flooding Higher extreme flood events

11 SEA-LEVEL RISE ADAPTATION Don t GetWet NC State Building Code 2 nd Oldest Hurricane Building Code in U.S. 1960s National Flood Insurance Program ~1970s

12 SEA-LEVEL RISE ADAPTATION FREEBOARD 100-YEAR FLOOD or 1% CHANCE EACH YEAR NO SAFETY FACTORS

13 ACCUMULATED RISK 100-Year Flood = 1% Risk Each Year 70-Year Average Building Lifetime = 51% 51% RISK OF EXCEEDANCE HEADS or TAILS!

14 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%

15 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*

16 FREEBOARD = 2 FEET NHC, Wilm & WB 2010 SEA LEVEL ~66 YEARS

17 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

18 SEA-LEVEL RISE ADAPTATION EROSION RATES CAMA Oceanfront Erosion Rate Setback Lines 1979

19

20 SEA-LEVEL RISE ADAPTATION What action needs to be taken? What are the most compelling reasons to take the action?

21 SEA-LEVEL RISE What to expect? More frequent, low elevation, nuisance flooding Higher extreme flood events

22 SEA-LEVEL RISE ADAPTATION HAZARD-RESILIENT RESILIENT COMMUNITIES Present not FUTURE CONDITIONS What If Sea Level Does Not Rise? Historical Hazards The Third Annual Storm of the Century Do it like Ike!

23 HURRICANE IKE

24 1938

25 SEA-LEVEL RISE ADAPTATION: Lessons from a Used-Car Salesman

26 1938

27 TOPSAIL ISLAND SHORELINE & BEACHFILL EXPECTATIONS SPENCER ROGERS NC Sea Grant CENTER FOR MARINE SCIENCE UNC-Wilmington CIVIL ENGINEERING NC State University

28 SEA-LEVEL RISE ADAPTATION in Coastal NC (in human terms) HAZARD-RESILIENT RESILIENT COMMUNITIES 1938 TARGET YOUR AUDIENCE

29

30

31

32

33

34

35

36 FREEBOARD = 1 FOOT Topsail B & Oak Island 2010 SEA LEVEL ~41 YEARS

37 CRC Science Panel 2015 SLR Update NC Tide Gauge Data

38 CRC Science Panel 2015 SLR Update IPCC RCP Scenarios + VLM Station IPCC RCP VLM RSLR in 30 years (inches) IPCCRCP85+VLM 8.5 RSLR in 30 years (inches) Mean Range Mean Range Duck Oregon Inlet Beaufort Wilmington Southport *Note: Projections were rounded to the nearest tenth of an inch.

39 CRC Science Panel 2015 SLR Update NC Tide Gauge Data

40 SEA-LEVEL RISE ADAPTATION EROSION RATES CAMA Oceanfront Erosion Rate Setback Lines 1979

41 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