1. Assessing Vulnerabilities to Sea
Level Rise in Hawaiʻi County
By: Devon Aguiar & Rufus Lakjit

2. What is Sea Level Rise (SLR)?
• SLR has been attributed to the melting of ice sheets and the thermal
expansion of warm seawater (Alley et al., 2005; Williams 2013).
Williams
(2013),
adapted from
Rekacewicz
(2005)
http://www.wired.co.uk/news/
www.wired.co.uk

3. • Predicted 1 ft. rise in global sea levels by mid century (2050) and 2.5-6.2 ft. rise
by end of the century (2100).
• The rate of sea-level rise in Hawaii is approximately 1.5 mm/ year (Fletcher et
al., 2012).
IPCC (2007) in Williams (2013)

4. • Assist County Planning Department in identifying
priority planning areas.
– Shoreline setback areas.
Objectives
Source: John P.

5. • Identify Special Management Areas (SMA):
“Therefore, special controls on development within the area along
the shoreline are necessary to avoid permanent loss of valuable
resources and the foreclosure of management options, and to insure
that adequate public access is provided to public-owned or used
beaches, recreation areas, and natural reserves, by dedication or
other means” (COH Planning Commission, Rule 9-2).
Objectives

6. • Identify cultural/natural resources at risk.
• Recreation areas.
• Culturally significant areas.
Objectives
http://www.ksbe.edu/

7. Shoreline Hazards on Hawaiʻi Island

8. Subsidence: Sinking of the Earth’s surface in
response to geologic or man-induced causes.
hvo.wr.usgs.gov

9. Erosion:Rates can range from 0.5-1 ft/yr (Fletcher et al., 2002)

10. Waves: Damage to property and endanger human life

11. Storms:
Over wash from high waves and damage from strong winds
KITV News

12. Sea Level Rise: 1.5 in/decade for Hawaiʻi Island
(Fletcher et al., 2002)

13. Methods
• Gather and analyze:
– Elevation data
– Shoreline Hazard data
– Cultural/Natural resource data
• Create inundation polygons and identify impacted land
parcels & cultural/natural resources.
• Hazard ratings: Moderately high & High risk

14. Honoliʻi
Hilo
Bayfront
Kapoho
Keaukaha

15. SLR
Results
This is a “Bathtub” model
Honoliʻi Kapoho
Bayfront & Keaukaha
1 ft. of SLR
3 ft. of SLR
6 ft. of SLR

16. Storm
Hazard
High
Moderately
High
Honoliʻi Kapoho
Bayfront & Keaukaha

17. Honoliʻi Kapoho
Bayfront & Keaukaha
Erosion
Hazard
Results
Moderately High
Moderately Low

18. Shoreline land parcels with < 20% slope (red) and >20% to <45% slope (yellow).
Use slope
data we
made
or
Compare to
ours
Honoliʻi Kapoho
Bayfront & Keaukaha

19. Explain that county
collected this data
Yes/no rated
Honoliʻi Kapoho
Bayfront & Keaukaha
Undergoing
Subsidence
No Subsidence

20. Honoliʻi Kapoho
Bayfront & Keaukaha
Moderately
high
Wave
Hazard

21. Wave
Hazard
High
North Kohala

22. Honoliʻi
Bayfront & Keaukaha
Kapoho
7 (Very High)
6 (High)
5 (Moderately High)
Overall
Hazard

23. Wave Hazard Erosion Hazard Storm Hazard
High 140 land parcels 27 land parcels 2,071 land parcels
Moderately High 4,771 land parcels 672 land parcels 5,376 land parcels
Moderately Low 2,629 land parcels 6,816 land parcels 93 land parcels
Low 0 land parcels 25 land parcels 0 land parcels
Total amount of shoreline land parcels: 7,540
Results

26. Further Implications of Study
• Addition of tidal data in our study.
• Use up to date elevation data (when it gets released…).
• Connectivity between groundwater and SLR.

27. Mahalo!
• Lisa Marrack, PhD. Candidate UC Berkeley
• Ryan Perroy, UH Hilo Geography & Environmental Science Dept.
• Chris, Nick, & Mark, UH Hilo SDAV
• Chip Fletcher, UHBethany Morrison and Drew Marshall, County of Hawaiʻi
Planning Department Manoa SOEST
• John P. Lockwood, Geohazards Consultants International Inc.