Report to the Thirty-Second Legislature
2023 Regular Session

SEA LEVEL RISE VULNERABILITY AND ADAPTATION REPORT

Prepared by theState of Hawaii Department of Land and Natural Resources,
Office of Conservation and Coastal Lands

In response to Act 32,of the Regular Session of 2017;

December 2022

Hawai`i Sea Level Rise
Vulnerability and
Adaptation Report
2022 Update

Hawai`i State Climate Commission

Acknowledgements
The Hawai’i State Climate Commission gratefully acknowledges the hard work of the project team forcompiling this report. The project team consists of Leah Laramee, Hawai‘i Climate Change Mitigation &Adaptation Coordinator, Dr. Bradley Romine and Amy Wirts of the University of Hawai`i Sea Grant
College Program, Dr. Charles Fletcher, Dr. Shellie Habel, Dr. Juliette Budge and Colin Lee, Esq of the
University of Hawai’i School of Ocean and Earth Sciences Climate Resilience Collaborative, and Amanda
Ho, Community Engagement and Climate VISTA.
Mahalo to the many representatives of state and county agencies who provided editing and information
regarding agency actions.

Table of Contents
Executive Summary
Introduction ..................................................................................................................................... i
Scientific Observations and Predictions .......................................................................................... i
Accomplishments and Progress .......................................................................................................ii
Key Statewide Accomplishments: ................................................................................................ii
Summary of Accomplishments ...................................................................................................iii
Next Steps .......................................................................................................................................iv

Hawai`i Sea Level Rise Vulnerability and Adaptation Report 2022 Update
Introduction .................................................................................................................................... 1
Sea Level Rise Outlook: Updated Global and Local Projections ..................................................... 1
Global and Local Sea Level Rise Trends....................................................................................... 1
Local Observations of Coastal Impacts ........................................................................................... 5
Viewer Updates and Guidance Documents .................................................................................... 6
Review of 2017 Recommendations ................................................................................................ 8
Progress Towards Meeting 2017 Recommendations: .............................................................. 8
Further Recommendations and Next Steps .................................................................................. 26
Recommendations .................................................................................................................... 26
Next Steps ................................................................................................................................. 31
Next Steps for the SLR Viewer................................................................................................... 32
Conclusion ..................................................................................................................................... 33
Works Cited ................................................................................................................................... 34

Appendix A - Responses to Learning Questions from 2017 Report
Sea Level Rise Outlook: Global and Local Observations and Projections .................................... A1
Methodology................................................................................................................................. A2
Results ........................................................................................................................................... A3
Recommendations ........................................................................................................................ A4

Hawai`i Sea Level Rise Vulnerability and Adaptation Report
2022 Update Executive Summary
Introduction
The 2017 Hawai`i Sea Level Rise Vulnerability and Adaptation Report (2017 Report) was mandated by
the Hawai`i Climate Change Adaptation Initiative (Act 83 (Session Laws of Hawaii (SLH) 2014)), andexpanded by the Hawai`i Climate Change Mitigation and Adaptation Initiative (Act 32, SLH2017).
Through this report the Legislature aimed to address the threat posed by climate change to theeconomic well-being, public health, natural resources, and environment of Hawai`i. The 2017 Report
was prepared in recognition that sea level rise (SLR) is an inevitable outcome of global warming that willcontinue far into the future, even with an immediate and drastic reduction of greenhouse gas emissions.
In addition to the preparation of the 2017 Report, Act 32 charged the Hawai`i Climate Change Mitigation
and Adaptation Commission to conduct a comprehensive review of implementation and submit a reportto the governor, legislature, and the counties no later than twenty days prior to the convening of theregular session of the 2023 Legislature and every five years thereafter. This document serves as the
five-year update to the 2017 Report and the Commission’s report on recent sea level rise adaptation
initiatives across State and County government, many of which are a direct result of the information andmap data provided by the 2017 Report and companion State of Hawai`i Sea Level Rise Viewer (Viewer).

Scientific Observations and Predictions
In 2017, and again in 2020, the Honolulu Harbor Tide gauge recorded its highest daily mean water levels
observed over its 112-year history. These record high water levels were produced by a combination ofphenomena that included long-term global sea level rise, peak annual astronomical tides (“king tides”),
wave setup, and migration of warm buoyant waters brought in by winds and currents. These events
provide a glimpse of what will become a more regular occurrence as sea level continues to rise. Local
impacts were observed throughout the State in the form of increased coastal erosion, minor wave overwash flooding, backshore flooding from groundwater rise and storm drain backflow, and impeded andpotentially hazardous beach access.
The United Nations Environment Program Emissions Gap Report, 2022 indicates that globally, nations
have missed the emissions goals that may have constrained overall global warming to 1.5o C, and thatgiven our current path and past actions, the world is likely to warm by 2.8oC by the end of the century.
Sea level responds to greenhouse gas emissions more slowly than global surface temperature. This slow
response leads to long-term committed SLR, associated with ongoing ocean heat uptake and the slow
adjustment of the ice sheets. The Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment
Report states with high confidence that “Global mean sea level will continue to rise for thousands ofyears, even if future CO2 emissions are reduced to net zero and global warming halted, as excess energy
due to past emissions continues to propagate into the deep ocean and as glaciers and ice sheets continue
to melt.” (Arias, et al. (2021)).
Sea level rise exposure mapping in the 2017 Hawai‘i Sea Level Rise Report and Hawaii Sea Level Rise
Viewer is based on an upper-end projection in the 2013 IPCC 5th Assessment Report of 3.2 feet of global
mean sea level rise by 2100. Since completion of the 2017 Report, peer-reviewed scientific literature asiwell as government and multinational reports increasingly point to 3 to 4 feet of sea level rise by 2100 asa mid-range, rather than high-end, scenario for Hawai‘i. Long-term observational data from local tidegauge stations show that sea level is rising around Hawai‘i. Models indicate that Hawai‘i and othertropical Pacific sites will experience sea level rise that is 16% to 20% higher than the global average(Sweet. et al. 2022). As the science progresses towards increasingly concerning rates of sea level rise for
Hawai`i, it remains imperative that the legislature and state and county agencies maintain a long-term
focus on building resiliency to rising seas by reducing overall vulnerability of infrastructure andimplementing adaptation measures to allow our state to continue to thrive with higher seas.

Accomplishments and Progress
The 2017 Report included nine recommendations with 49 recommended actions aimed at improving thestate’s capacity to address the social, economic, and environmental impacts of sea level rise.

Key Statewide Accomplishments:
Use of the Sea Level Rise Exposure Area Data and Sea Level Rise Viewer: Although the Sea Level Rise
Exposure Area (SLR-XA) was not officially recognized as a state-wide vulnerability zone, the Viewer and
SLR-XA are in widespread use by state and county agencies for adaptation planning purposes.
Hawai`i Coastal Zone Management Act Updates: Act 16, SLH2020 updated the Hawai`i Coastal Zone
Management Act (HRS Chapter 205A) including strengthening protections for beach and other coastal
environments by specifically prohibiting private shoreline hardening structures and minimizing publicshoreline hardening structures, including seawalls and revetments, at sandy beaches where they wouldinterfere with existing recreational and waterline activities.
Sea Level Rise Report Addendum: The Guidance for Using the Sea Level Rise Exposure Area in Local
Planning and Permitting Decisions was published by the State as a supplement to the 2017 Report. The
Addendum was prepared by the University of Hawai`i Sea Grant College Program (Hawai`i Sea Grant)with the Hawai`i Department of Land and Natural Resources - Office of Conservation and Coastal Lands(OCCL) for the Hawai`i Climate Change Mitigation and Adaptation Commission - Climate Ready Hawai`i
Initiative. The Hawai`i Climate Change Mitigation and Adaptation Commission issued a statement ofapproval for the Addendum at its October 28, 2020 meeting.
Hawai`i 2018 Hazard Mitigation Plan: The 2018 update of the State’s Hazard Mitigation Plan includes
expanded consideration of climate change and sea level rise hazards, including hazard assessment using
the SLR-XA and a 1% Annual-Chance Coastal Flood Zone with 3.2 feet of sea level rise (1%CFZ-3.2)
modeled for the Plan: https://dod.hawaii.gov/hiema/sert-resources/hazard-mitigation/
Planning for Managed Retreat: The Office of Planning and Sustainable Development Coastal Zone
Management Program (OPSD-CZM) published a report titled Assessing the Feasibility and Implications ofManaged Retreat Strategies for Vulnerable Coastal Areas in Hawai`i in 2019 and is embarking on a nextstep study that will assess the options for and implications of implementing managed retreat from theperspectives of (1) policy and regulation, and (2) funding and financing mechanisms in 2023.
Statewide Inventory of Vulnerable Infrastructure: Act 178 Relating to Sea Level Rise Adaptation was
passed to begin the long-term planning needed to effectively address climate impacts. OPSD-CZM
submitted a report to the legislature in 2021 reporting on progress towards the phased approachrequired by Act 178.
ii

Summary of Accomplishments
Progress towards meeting the nine recommendations (represented by large circles) and 49 associatedrecommended actions (represented by small circles underneath) is presented here as measured on aqualitative scale of “no known progress” to “significant progress” as depicted by the following key:iii

Next Steps
New and updated recommendations provide a roadmap for bridging from this interim report to a full,comprehensive Sea Level Rise Vulnerability and Adaptation Report in 2027. This Report Update
recommends continuing work on the nine 2017 Recommendations and associated recommended
actions, and adds two new 2022 Recommendations with supporting recommended actions.
2022 Recommendation 1 is to fund and conduct a comprehensive update of the Sea Level Rise
Vulnerability and Adaptation Report in 2027, and 2022 Recommendation 2 is to continue to implement
the 2017 Recommendations with minor edits as outlined in this 2022 Report Update. The
recommended actions within these two new recommendations provide a framework for further
identifying gaps in progress since 2017 and meeting the overall goals of this initiative. A key updated
recommended action is for the state to set a revised planning and policy benchmark of 4 ft (up from the2017 guidance of 3.2ft) as the minimum scenario for all planning and design based on the report’s
Intermediate (mid-range) scenario for Hawai`i of 3.9 feet of sea level rise by 2100, and apply a 6 ft
benchmark for planning and design of public infrastructure projects and other projects with low
tolerance for risk based on the report’s Intermediate High scenario for Hawai`i of 5.9 feet of sea level
rise by 2100.
In addition to the recommendations, this report has identified the following unmet needs and areas inneed of focus in the next five years which should be set as priority action areas from 2023-2027.
●

●
●
●
●
●
●

Facilitate interagency coordination for holistic adaptation planning (e.g., comprehensive
consideration and planning for natural resources, roads, communities; and improved
communications between government agencies) (2017 Recommendation 9, 2022
Recommendation 1)
Conserve and adapt Native Hawaiian cultural resources and sites (2017 Recommendation 5)
Integrate equity and justice considerations to vulnerability assessments and adaptation
planning and actions (2017 Recommendation 2)
Address and stop the loss of shoreline access (2017 Recommendation 4)
Integrate economic valuation and ecosystem co benefits of natural coastal resources intoplanning and actions (2017 Recommendations 4, 5 and 8)
Make managed retreat a viable option and identify funding mechanisms for adaptation (2017
Recommendations 2 and 7)
Implement phased adaptation to sea level rise (2017 Recommendation 1, 2, 7)

Our understanding of the sea level rise outlook has improved since the 2017 Report and we now have abetter understanding of the most probable impacts of sea level rise in Hawai`i. This Updated Report andthe recommendations within should be used as a tool by the decision makers of the State, the Counties,
and community leaders. Recommendations to increase our capacity to adapt to sea level rise should be
implemented across the levels of government now to address the inevitable near and medium-term riseof sea level rise.

iv

Hawai`i Sea Level Rise Vulnerability and Adaptation Report
2022 Update
Introduction
The 2017 Report provided the first detailed statewide assessment of Hawaii’s exposure to sea level rise
related hazards and proposed recommendations to reduce the state’s vulnerability to sea level rise andincrease our capacity to adapt. This report is intended as a five-year update to the 2017 Report and is
not a full review or stand-alone document. Instead, it refers to the 2017 Report and provides an
overview of updates to climate and sea level rise science, the accomplishments achieved relative to the2017 Report recommendations, and provides updated recommendations for the next five years andbeyond. “Learning Questions” posed by the 2017 Report are directly addressed in Appendix (A) of thisReport.

Sea Level Rise Outlook: Updated Global and Local Projections
The 2017 Hawai`i Sea Level Rise Vulnerability and Adaptation Report provided a detailed overview ofclimate science and sea level rise observations and predictions based on the latest and best-available
science at that time including the Intergovernmental Panel on Climate Change Fifth Assessment Report(IPCC AR5) and the U.S. Global Change Research Program (USGCRP) 4th National Climate Assessment.
As expected, climate and sea level rise science has continued to advance since the 2017 Report, withlandmark intergovernmental reports including the IPCC AR6 in August 2020 and NOAA-led Sea Level Rise
Technical Reports in 2017 and 2022. An update on Sea Level Rise Science was provided as an appendix in
an October 2020 Hawai`i Climate Change Commission document, Guidance for Using the Sea Level Rise
Exposure Area in Local Planning and Permitting Decisions - A Supplement to the Hawai`i Sea Level Rise
Vulnerability and Adaptation Report. In July 2022, the City and County of Honolulu Climate Change
Commission provided an updated guidance document on the latest sea level rise science and projections
with recommendations for adaptation planning. This section provides an overview of the latest climate
science and sea level rise projections published in those documents with specific regional and local
projections and likely impacts.

Global and Local Sea Level Rise Trends
Sea level rise exposure mapping in the 2017 Hawai`i Sea Level Rise Report and Hawai`i Sea Level Rise
Viewer (Viewer) is based on an upper-end projection in the 2013 IPCC 5th Assessment Report of 3.2 feetof global mean sea level rise by 2100. As expected, the science on sea level rise observations andforecasts has continued to advance. Since completion of the 2017 Report, peer-reviewed scientific
literature as well as government and multinational reports increasingly point to 3 to 4 feet of sea level
rise by 2100 as a mid-range, rather than high-end, scenario for Hawai`i. These increasing projections ofsea level rise are based on greenhouse gas emissions, which continue to increase, and observations ofaccelerating ice mass loss to the oceans, particularly from Greenland and West Antarctica. The
projections are often provided to 2100, though sea level rise will likely continue for centuries.

1

Since 1993, 27 years of continuous satellite altimeter measurements tied to tide gauges and averaged
across the planet (Figure 1) show that global mean sea level is not only rising at a rate of 3.4 mm/yr (1.3
inches per decade, sealevel.nasa.gov), it is accelerating at a rate that will lead to 23 cm (9 inches) ofglobal mean sea level rise by 2050 (relative to the year 2000; Nerem et al., 2022). Continued global
warming is expected to increase this rate of acceleration, and therefore 9 inches of sea level rise by
2050 is likely a conservative (low-end) sea level rise scenario for that timeframe.

Figure 1. Global mean sea level is rising at a rate of 3.4 mm/yr (1.3 inches per decade, sealevel.nasa.gov) and thisrate is accelerating (Figure: Nerem et al., 2022).

The most recent projections of global and regional sea level rise are published in a 2022
intergovernmental report led by NOAA (Sweet et al. 2022). The 2022 report builds on a 2017 NOAA
report (Sweet et al., 2017) and global mean sea level rise scenarios from the United Nations
Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6; IPCC 2021). Key
findings of the NOAA 2022 report include:●●●

Increased confidence, regardless of Greenhouse Gas (GHG) emissions scenario, in sea level rise
projections at 2050 with sea level expected to rise as much over the next 30 years as it has overthe last 100 years.
An increase in magnitude and frequency of coastal flooding by 2050 from high tide and storm
surge flood events with significant consequences to coastal infrastructure, communities, andecosystems.
A 50% probability of exceeding 0.5 m (1.6 ft) of sea level rise globally by 2100 with an increase inaverage global temperature of 2°C above preindustrial levels (global temperature has alreadyrisen 1.01°C since 1880). The probability of exceeding 0.5 m (1.6 ft) of global sea level riseincreases to 80% to 99% under higher GHG emissions scenarios with 3°-5°C of warming,
respectively. These probabilities do not consider the potential for faster-than-projected ice

2●

sheet losses in Antarctica and Greenland within this century, which is a focus of ongoing
research.
There is a 50% probability of exceeding 1.0 m (3.3 ft) and 10% probability of exceeding 2.0 m(6.6 ft) of global sea level rise by 2100 when considering a high GHG emissions scenario that
leads to an average global temperature increase of 5°C plus the impact of earlier and faster ice
sheet losses from Antarctica and Greenland. While physically plausible, the likelihood ofwidespread ice sheet collapse to that extent within this century is currently unknown and is anactive area of ongoing observation and research.

Long-term observational data from local tide gauge stations show that sea level is rising around Hawai`i.
Models indicate that Hawai`i and other tropical Pacific sites will experience sea level rise that is 16% to
20% higher than the global average (Sweet. et al. 2022). The NOAA 2022 report provides a range ofregionalized sea level rise scenarios based on differing GHG emissions pathways and associated global
warming and ice sheet melt (all projections relative to sea level in the year 2000):●●●●

Sea level will rise around Hawai`i between 0.7 and 1.5 feet by 2050.
The Intermediate (mid-range) estimate is for a rise of 1.0 feet by 2050.
Sea level will rise between 1.3 and 8.0 feet by 2100.
The Intermediate (mid-range) estimate is for a rise of 3.9 feet by 2100.

Figure 2. Sea level rise observations (solid black line), extrapolated observed trend (dashed black line), and sea
level rise scenarios Hawai`i from NOAA interagency sea level rise report (Sweet, et al. 2022). The text in the figure3describes the various processes and uncertainties that contribute to the various sea level rise scenarios (Figure by
Jamie Carter, NOAA).

Year
Scenario

2050

2100

Low

0.7

1.3

Intermediate-Low

0.9

2.0

Intermediate

1.0

3.9

Intermediate-High

1.3

5.9

High

1.5

8.0

Units in feet relative to year 2000
Table 1. Sea level rise scenarios for 2050 and 2100 for Hawai`i from interagency report (Sweet, et al. 2022).

In a study by researchers at the University of Hawai`i Sea Level Center and others, it was reported that
rapid increases in tidal flooding are expected to begin locally by the mid-2030’s (Thompson, et al. 2021).
This increase will be the result of ongoing sea level rise in combination with natural cyclicity in tidal
amplitudes, i.e., natural variations in the highest high tides. By the early 2040’s Honolulu is projected toexperience 2 to 3 high tide flood days per month considering NOAA’s intermediate SLR scenario.
However, such high tide events will be clustered over times of the year when tides are at their peak (i.e.,during “king tides”), in which as many as 6-14 days per month can be expected. Thus, researchers
recommend that compound flood impacts during these more extreme periods of tidal flooding beconsidered in flood management planning instead of annual averages (Thompson, et al. 2021).
Compound flooding describes flood sources that are additive to that generated by sea level rise alone.
Compound flood sources can include the shallowing or emergence of coastal groundwater, rain events,and overwhelming of drainage systems that can ironically act as additional sources of floodwater. In a
study that investigated proportions of flooding in Honolulu’s Primary Urban Core caused by single,
versus multiple components of sea level rise induced inundation, it was found that less than three
percent was caused solely by direct overland connection to a rising ocean. Sources of compoundflooding and exacerbation of such flooding by rising sea level should be a top consideration as part ofongoing research and flood management planning.
4Local Observations of Coastal Impacts
The 2017 Report provided a detailed outline of the statewide results of the vulnerability assessment
based on the outputs of the SLR-XA model and Viewer. Vulnerability was assessed in terms of potential
impacts to land use, people, property, cultural and natural resources, and critical infrastructure. Thissection provides an overview of the observed local impacts since 2017 to inform the application of the
SLR-XA to current and future planning efforts. This report does not include an updated assessment of
the potential economic loss or impacts on people, roads, other infrastructure and ecological features
within the SLR-XA. Such analyses will be included as part of planned updates to the Report and Viewer.
As was identified in the 2017 Report, chronic coastal flooding within the SLR-XA is an ongoing problem.
The consequences of elevated sea level have already become apparent. In 2017, and again in 2020, theHonolulu Harbor Tide gauge recorded its highest daily mean water levels observed over its 112-year
history. These record high water levels were produced by a combination of phenomena that included
long-term global sea level rise, peak annual astronomical tides (“king tides”), wave setup, and migrationof warm buoyant waters brought in by winds and currents. These events provide a glimpse of what will
become a more regular occurrence as sea level continues to rise. Local impacts were observed
throughout the State in the form of increased coastal erosion, minor wave over-wash flooding,backshore flooding from groundwater rise and storm drain backflow, and impeded and potentiallyhazardous beach access.
In addition to the observed coastal flooding, elevated water levels and recent extreme rainfall events
have spurred concern regarding the functionality of municipal drainage systems, especially acrossheavily developed low-lying areas. Drainage systems in these areas were designed to convey
stormwater from higher elevation to lower elevation waterways. As sea level rises, differences in theseelevations have become reduced, and at times reversed, such that drainage systems are becoming
increasingly inundated even in the absence of rainfall. Additionally, it is typical for these systems tofeature cracks that can allow surrounding elevated groundwater to enter, further reducing drainage
capacity. Reverse flow of stormwater is commonly observed in locations like Mapunapuna and Waikiki
on O`ahu. Present drainage issues illustrate the fact that coastal flooding will increasingly be generated
by a variety of flood sources including the contribution from stormwater conduits, particularly during
heavy rainfall events.
The progressive impacts of sea level are likewise evident in the form of chronic coastal erosion. As
expected, such erosion has continued along the majority of the State’s coastlines, resulting indegradation of public access and nearshore infrastructure. Coastlines along West Maui and O`ahu’s
North Shore have become particularly stricken by the loss of coastal public trust lands and damage tobackshore assets. An aggressive episode of coastal erosion in early 2022 critically undermined one single
family home, leading to its collapse and deposition of dangerous debris along Pupukea Beach Park. The
collapse followed four years of a progressively worsening combination of chronic and seasonal erosion
between Rocky Point and Sunset Beach Park in Paumalu that has become a focal point, highlighting theneed for improved management and retreat strategies. In West Maui, chronic erosion along stretches ofKa`anapali and Kahana have spurred the development of several beach and dune restoration projects
with the goal of serving as natural buffers to ongoing erosion. Similarly, the degradation of coastal areas
along West Maui has become a flashpoint for debate regarding public access rights to public trust5resources, private property rights, and environmentally appropriate coastal management strategies.
Seasonal erosion along Ka`anapali in Summer 2022 exceeded recent historical records, revealing derelict
erosion control efforts such as sandbags and highway barriers placed during the summer of 2007. The
2022 summer erosion resulted in the loss of trees and undermined the concrete beachwalk. Although
the area is experiencing seasonal recovery, the shoreline has migrated mauka and similar erosion events
can be expected in the future.
The impacts of coastal erosion on the state highway system are also significant. Hawai`i Department ofTransportation (HDOT) Highways is proposing revetments in at least two locations along theKamehameha Highway on O`ahu to protect the threatened roadway. On Maui, HDOT-Highways
proposes to move portions of Honoapi`ilani Highway inland as a sea level rise adaptation. HDOTHighways is also exploring the use of sand-savers and a revetment to protect against future erosion
events in Wailua, Kaua`i and along the Windward O`ahu coastline.

Viewer Updates and Guidance Documents
The State of Hawai`i Sea Level Rise Viewer (Viewer) is the online atlas that supports the 2017 Report.
The Viewer is designed to be useful for policy makers, government officials, and the public. There is an
ongoing effort to refine the Viewer to continually provide the best available information to the users
and stay in line with current science, observations, and projections. This section provides an overview of
updates made to the Viewer to-date and modeling upgrades in progress to further refine theinformation provided by the Viewer.
In November 2018, the disclaimer text was updated in the Report and Viewer with the State Climate
Commission’s approval, stating that “having gone through peer review and publication in the Nature
Journal Scientific Reports, the results of this study are sufficiently validated to be appropriately used inland management decisions as the best available information…”
In 2020, the State published the Sea Level Rise Report Addendum: Guidance for Using the Sea Level
Rise Exposure Area in Local Planning and Permitting Decisions as a supplement to the 2017 Report.
The Addendum was prepared by the University of Hawai`i Sea Grant College Program with the Hawai`i
Department of Land and Natural Resources - Office of Conservation and Coastal Lands for the Hawai`i
Climate Change Mitigation and Adaptation Commission - Climate Ready Hawai`i Initiative. The Hawai`i
Climate Change Mitigation and Adaptation Commission issued a statement of approval for the
Addendum at its October 28, 2020 meeting.
The primary purpose of the Addendum is to assist state and county planners, natural resource andinfrastructure managers, and others with understanding and using the Sea Level Rise Exposure Area
(SLR-XA) from the Report and Viewer in day-to-day planning and permitting decisions, particularly at the
project or property-level scale. This guidance was developed in response to requests from county
planning departments and other stakeholders to provide information on how to appropriately interpretand apply the SLR-XA map data in land use planning and permitting decisions while increasing
understanding of the methods, assumptions, and limitations of the data.

6

Within the Viewer, several updates to the supporting text and available layers were completed since2017 with the goal of making the tool more accessible and useful to users:● An address and TMK search tool and a TMK Parcels boundary layer were added in response to
the Disclosure Requirement for Residential Real Estate in the Sea Level Rise Exposure Area .
These updates were made as a result of discussions with the Hawai`i Realtors Association to
enable meaningful implementation of the requirement beginning in May 2022.
● A passive flooding exposure layer at 6 feet of sea level rise from NOAA was added in support ofplanning guidance to consider greater than 3.2 ft of sea level rise for critical infrastructure.
● Layers depicting moku and ahupua`a boundaries were added to support visualization andunderstanding of sea level rise hazards in a community and cultural context.
● A 1%-Annual-Chance Coastal Flood Hazard Zone with Sea Level Rise layer from the Hawai`i State
Hazard Mitigation Plan was added to depict changing coastal flood hazard risks with lessfrequent but more severe storm and wave events● A Land Use Districts layer was added in support of community planning for sea level rise.
● The text within the section titled “Sea Level Rise Projections for Modeling” was updated withthe latest science.
● Text describing Assumptions and Limitations for the SLR-XA and three component models:Passive Flooding, Annual High Wave Flooding, and Coastal Erosion were added to improveunderstanding and transparency.
As sea level rise science and projections continue to evolve, the Viewer will be updated to incorporate
new data and subsequent model outputs. The Coastal Erosion exposure map data in the Viewer was
updated for Kaua`i, O`ahu, and Maui in 2020 by the University of Hawai`i Coastal Geology Group.
However, the combined SLR-XA was not updated accordingly. A timeline and outline for
implementation of a fully updated version of the Viewer is included in the Next Steps and Future
Recommendations Section at the end of this report.
The Viewer was updated to provide specific local data for West Maui in the West Maui Wave Flooding
Tool and Wave Runup Forecast Tool.
In addition to the Viewer, the State has published other related guidance and tools building on the 2017
Report. These efforts are listed below:● State of Hawai`i Climate Adaptation Portal - HI Adaptation site: https://climate.hawaii.gov/hiadaptation/●

Sea Level Rise Guidance Tool: interactive web-based guide to incorporate sea level rise
considerations into planning and permitting: https://climate.hawaii.gov/hi-adaptation/sealevel-rise-viewer-flowchart/●

Guidance for Addressing Sea Level Rise in Community Planning: This project led by Hawai`i
Sea Grant in partnership with Hawai`i Department of Land and Natural Resources (DLNR) and
Office of Planning & Sustainable Development - Coastal Zone Management Program (OPSDCZM) worked with state and county government to produce a guidance document and conduct
outreach to address sea level rise and coastal hazards in the county general and community
planning process: https://seagrant.soest.hawaii.edu/resources/program-publications●

Guidance for Disaster Recovery Preparedness in Hawai`i: This project led by Hawai`i Sea Grant
in partnership with Hawai`i DLNR and OPSD-CZM worked with state and county government to7

establish resilience-focused recovery practices before a disaster hits to enable communities torecover quickly while also adapting to sea level rise and protecting sensitive coastal
environments through recommended preparedness activities and model planning and policy
resources: https://seagrant.soest.hawaii.edu/resources/program-publications●

Assessing the Feasibility and Implications of Managed Retreat Strategies for Vulnerable
Coastal Areas in Hawai`i: This report by OPSD-CZM examined managed retreat programs thathave been successfully implemented in post-catastrophic events and in response to chroniccoastal hazards and reviewed if and how the programs may be applied to Hawaiʻi. The
assessment identified next steps and key questions to further understanding of how to
implement retreat: https://planning.hawaii.gov/czm/ormp/ormp-action-team-project-on-thefeasibility-of-managed-retreat-for-hawaii/●

Hawai`i 2018 Hazard Mitigation Plan: The 2018 update of the State’s Hazard Mitigation Plan
includes expanded consideration of climate change and sea level rise hazards, including hazard
assessment using the SLR-XA and a 1% Annual-Chance Coastal Flood Zone with 3.2 feet of sea
level rise (1%CFZ-3.2) modeled for the Plan: https://dod.hawaii.gov/hiema/sertresources/hazard-mitigation/

Review of 2017 Recommendations
The 2017 Report included nine recommendations with 49 recommended actions to achieve the desired
outcomes. The recommendations were focused on improving our capacity to address the social,economic, and environmental impacts of sea level rise. Over the past 5 years, the legislature andvarious state and county agencies undertook several initiatives which align with the recommendations
and goals set out in the 2017 Report. This section provides an overview of the status of thoserecommendations and associated recommended actions. Several of the initiatives are in progress or are
ongoing efforts to continually adjust and address the threats of sea level rise and coastal erosion. In
many cases, an initiative may address more than one recommendation or recommended actions. In
those cases, the initiative is listed under each recommended action it addresses to give a complete
picture of the state’s progress towards meeting the goals of the 2017 Report.
Each recommendation and recommended action listed here will be noted with either a description of
how it has been addressed, the ongoing efforts to address it, or flagged as unaddressed. All existing
recommendations should be continued to the 2027 Report, with a few updates as detailed in the
Further Recommendations Section towards the end of this report. The 2017 Report contains detailed
descriptions and reasoning for each recommendation; readers can refer to that report for further
information regarding the purpose and goal of the recommendations. This Report does not provide anassessment of the reduction in vulnerability as a factor of exposure, sensitivity, and adaptive capacity inresponse to the actions taken.

Progress Towards Meeting 2017 Recommendations:
A summary of the progress towards meeting the recommendations and recommended actions ispresented here as measured on a qualitative scale of “no known progress” to “significant progress” asdepicted by the following key:8

● 1.1 Recognize the SLR-XA as a state-wide vulnerability zone: The State has not officially adopted
SLR-XA as a statewide vulnerability zone but has made a number of important steps including
the following:o The Hawai`i Climate Change Mitigation and Adaptation Commission adopted the
Hawai`i Sea Level Rise Vulnerability and Adaptation Report (and recommendations
therein) and the Hawai`i Sea Level Rise Viewer following their completion in December
2017, recognizing the SLR-XA as a statewide vulnerability zone.
o The State Climate Commission adopted Recommendations for Countering Impacts of
Sea Level Rise (September 2018) including the following recommended strategies:▪ Support legislation for disclosure for private property and public offerings
located in areas with potential exposure to sea level rise.
▪ Request all new development, redevelopment and modifications be directedaway from beach areas.
▪ Urge counties to incorporate the 3.2 ft. sea level rise exposure area (SLR-XA)
into their general and development plans.
▪ Encourage agencies and non-governmental utility providers to identify andprioritize assets within the 3.2 ft SLR-XA or more as described in the State’s Sea
Level Rise report, identify adaptation measures, and to provide a status updateon this activity annually to the Climate Commission.
▪ Support legislation that funds State programs to meet mitigation goals, and tobring resources to assist in planning and implementation for sea level rise andother climate related impacts.
o Honolulu Mayor Directive 18-02 (July 16, 2018) requires all City departments to use themost current versions of the City Climate Change Commission’s Guidance andaccompanying Brief, and the 2017 Report and associated Hawai`i Sea Level Rise Viewer
as resources for managing assets, reviewing permitting requests, and assessing project
proposals▪ City Climate Change Commission Sea Level Rise Guidance (2017, updated in2022) builds on findings of the 2017 Hawai`i Sea Level Rise Report and recent
scientific literature to provide specific policy and planning guidance on
responding to sea level rise by the City.
o A Maui Mayoral Proclamation (February 22, 2018) directs County departments to use
the 2017 State Sea Level Rise Report, Viewer, and SLR-XA in their plans, programs, andcapital improvement decisions.
9oCounty of Kaua`i incorporated SLR-XA into West Kaui`i Community Plan

● 1.2 Seek opportunities to plan new development outside of the SLR-XA under long-term,

comprehensive managed retreat strategy
o OPSD-CZM published a report titled Assessing the Feasibility and Implications ofManaged Retreat Strategies for Vulnerable Coastal Areas in Hawai`i in 2019 and isembarking on a next-step study that will assess the options for and implications of
implementing managed retreat from the perspecives of (1) policy and regulation, and(2) funding and finacing mechanisms in 2023.
o Act 223, SLH2022 expands the authority of the counties to transfer development rights
to address areas at risk of sea level rise, coastal erosion, storm surge, or flooding
associated with climate change.
o The 2022 Draft update to the City and County of Honolulu Primary Urban Center
Development Plan includes a Sea Level Rise and Coastal Hazards Planning Chapter andstates Goal SLR-2: Conduct Long-Range Planning to Increase Area-Wide Adaptation andResilience; Policy SLR 2.1: Plan for priority growth areas outside of the 3.2’ SLR-XA and
6’ SLR, and vent proposed solutions for highly impacted areas with the community.
o Bill 10 (2022) currently before the Honolulu City Council, Relating to Use Regulations
would further expand the authority of Honolulu City and County to use transfer ofdevelopment rights to support retreat from areas at risk of flooding and coastal erosion.
o Molokai Molokai Climate Change and Sea-Level Rise Adaptation and Resiliency(CCSLAR) Master Plan is a community-led climate change & sea-level rise plan for
Molokai's future. Our overarching goal is to develop a Climate Change and Sea Level
Adaptation and Resiliency (CCSLAR) Plan that best serves our Molokai community. It
identifies areas at risk from sea level rise and areas for potential relocation.
o West Maui Community Plan (effective January 31, 2022) Section 2 Policies, Goal 2.1
Ready and Resilient Systems includes the following:▪ 2.1.1 | Proposed Community Plan Amendments for new development on
existing golf course land in Kā‘anapali makai of Honoapi‘ilani Highway should beapproved only for existing shoreline development that is retreating inland
because of impacts from sea level rise or other coastal hazards.
▪ 2.1.2 | To minimize impacts from future coastal erosion, new permanent
structures must be located landward of the State-recognized SLR-XA for coastal
erosion, except a minimum buildable area must be provided. This restriction
does not apply to structures needed as part of an approved beach restoration
project or cultural project, such as loko i‘a, and which must be evaluated on acase-by-case basis.
▪ 2.1.3 | For redevelopment and new developments within the SLR-XA,
developers must proactively: a. Coordinate with the Maui County Department
of Planning and adjacent or nearby property owners to understand possible
collective relocation of at-risk structures; b. Incorporate results of coordination
into development plans by siting any new planned structures out of harm’s way;c. Make efforts to not hold the County of Maui and State of Hawai‘i liable forany and all future costs associated with maintaining or protecting the property
developed within the SLR-XA, including costs associated with retreat, hazard
mitigation, and cleanup costs to maintain the health of the nearshore marine
environment from material debris originating from the ocean or from the
10

o

o

●

structures’ own erosion; and d. Make efforts to waive the ability to everrequest shoreline hardening for their property or project from the County ofMaui or the State of Hawai‘i.
The County of Maui adopted a Managed Retreat Revolving Fund in 2022 to take effect inJuly 2023. The fund is intended to help Maui homeowners manage coastal erosion andaddress climate change. The fund will specifically support shoreline improvements andthe in-land relocation of infrastructure owned by the county and private entities. The
money will come from 20% of the county's transient accommodations tax.
West Kaua`i Community Plan (adopted 2020)▪ Includes Objectives (page 65) to provide a higher elevation area for property
owners with vulnerable homes to retreat to in the future via transfer ofdevelopment rights or land swap opportunities and that evacuated land serves
as a buffer against future coastal hazards.
▪ Encourages new development outside of the SLR-XA through zoning
amendments. Several implementation zoning amendments were also approved
with the plan document. This included ZA-2020-9, which established a new
special treatment district called “ST-Coastal Edge” in the CZO. The new district
was implemented in all residential neighborhoods vulnerable to sea level riseand located makai of a public road. Any use, structure, or development
permitted with or without a Use Permit in the Special Treatment Coastal Edge
District shall mitigate impacts from coastal hazards.
▪ Identifies managed retreat as a priority as reflected in Resiliency Policy #1:
Adapt West Kauai’s low lying neighborhoods for climate change impacts and lay
the groundwork for managed retreat

1.3 Conduct an inventory of existing lands designated for urban use that are located outsideof the SLR-XA and prioritize these areas for new development
o The 2022 Draft of the revised Primary Urban Center Plan for the City and County of
Honolulu includes the following Growth and Development Policy Goal: Invest in longterm growth in commercial corridors and mixed-density neighborhoods outside of the
Sea Level Rise Exposure Area (SLR-XA). The goal contains an action to identify andcreate a geographic catalog of underutilized sites. Share these infill opportunities with
non-profit developers.

● 1.4 Strive to balance managed retreat strategies from vulnerable urban areas with preservationof agriculture and conservation lands by relying on state planning act policies and tools and theState Land Use Commission boundary review process.
o No known action.

● 1.5 Integrate sea level rise adaptation plans and policies into state, county and community plansoooHawai`i Sea Grant with State DLNR and OPSD-CZM developed Guidance for Addressing
Sea Level Rise in Community Planning in 2020 in conjunction with county planningdepartments.
In 2021, Hawai`i Department of Transportation (HDOT) Highways Division released its
Climate Adaptation Action Plan, exposure assessments, and hazard viewer.
Statewide Transportation Planning Office (STPO) is developing the 2045 Hawaii
Statewide Transportation Plan (HSTP), an overarching policy document to guide system11

level and master plans for the three primary modes of transportation in Hawaii.
Currently, the HSTP draft plan is undergoing review and the STPO is seeking publiccomment via online public survey to help better determine feedback on the strategies
that can help to implement the goals and objectives of the HSTP. You may find out more
information regarding the HSTP at https://arcg.is/1KmHSP and participate in the public
survey at https://www.surveymonkey.com/r/J8RHRTT.
o The draft Department of Hawaiian Homelands (DHHL) General Plan, currently underfinal review, includes a Technical White Paper on Climate Change Impacts & Adaptation
Planning with climate change adaptation strategies for sea level rise, erosion, andflooding. The draft General Plan incorporates climate change mitigation and adaptation
concepts and measures into the agency’s long-term vision, goals, objectives and policies,
as well as DHHL's statewide land use designations, and proposes establishing overlays orother mechanisms that can be applied to areas subject to sea level rise and otherclimate-related hazards.
o The Hawai`i Department of Transportation (HDOT) published the Statewide Coastal
Highway Program Report in 2019. The objective of the project was to develop ascientifically rigorous methodology to assess and rank the susceptibility of State of
Hawaii coastal roads to erosion and structural degradation due to ocean hazards such as
waves, currents, tides and sea level rise.
o HDOT’s Act 100 Resiliency Report outlines the work HDOT is performing to incorporate
resilience into its programs and projects.
o Draft Primary Urban Center Development Plan and North Shore Sustainable
Communities Plan, currently in review from the Honolulu Planning Department include
detailed consideration of sea level rise hazards with proposed actions informed bytechnical papers on climate change and sea level rise risks specific to the urban
Honolulu and North Shore regions.
o East Honolulu Sustainable Community Plan, updated in 2022, addresses sea level riseand SLR-XA in hazard planning, zoning and permitting.
o Ko`olauloa Sustainable Community Plan, updated in 2020, sets a policy for open space
to be used to provide adequate shoreline setbacks that consider shoreline changes
resulting from erosion hazards and rising sea levels, based on adopted projections ofshoreline erosion rates and sea level rise. The Plan also prioritizes using best-available
sea-level rise science as a basis for planning.
o West Maui Community Plan adopted into Ordinance by the Maui County Council in
December 2021 includes detailed sea level rise considerations and policy guidance
informed by community input and a Climate Change and Sea Level Rise TechnicalResource Paper.
o South Maui Community Plan currently in review includes detailed consideration of sea
level rise informed by a Climate Change & Hazards Resource Papero The draft Hawai`i County General Plan, currently in review, includes a section on
Mitigating & Adapting to Hazards and Climate Change including sea level rise informedby the SLR-XA.
o West Kaua`i Community Plan (adopted in December 2020) includes detailed sea level
rise vulnerability and adaptation considerations and recommendations informed in-partby a West Kaua`i Community Vulnerability Assessment.
o Waimea 400 Conceptual Master Plan, which is a master plan for the 417-acre parcel
between Kekaha and Waimea that was purchased by the County of Kauaʻi in 2019,
integrates the principles of Adaptation Planning in anticipation of sea level rise, flooding,12

groundwater intrusion and climate change impacts within the vulnerable areas of theproperty. Preliminary zones were created based on existing information on potential
inundation and future flooding. Appropriate uses for the conditions of each zone wereidentified.

● 1.6 Develop shoreline protection, conservation, and restoration priorities and guidelines
o

o

o
o

o

o
o

o

Act 16, SLH2020 updated the Hawai`i Coastal Zone Management Act (HRS Chapter
205A) in many ways including strengthening protections for beach and other coastal
environments by specifically prohibiting private shoreline hardening structures andminimizing public shoreline hardening structures, including seawalls and revetments, atsandy beaches where they would interfere with existing recreational and waterline
activities. Further, the legislature amended HRS §205A-46 to change the standard for avariance for private facilities to clarify that “a variance to artificially fix the shoreline
shall not be granted in areas with sand beaches or where artificially fixing the shoreline
may interfere with existing recreational and waterline activities unless the granting of
the variance is clearly demonstrated to be in the interest of the general public…”.
Act 16, SLH2020 also updated HRS Chapter 205A to increase protections of “valuable
coastal ecosystems, including reefs, beaches, and coastal dunes, from disruption andminimize adverse impacts on all coastal ecosystems.” Underline indicates addition fromthe former language. Further, it now refers specifically to protecting “beaches andcoastal dunes for: (i) Public use and recreation; ii The benefit of coastal ecosystems; and(iii) Use as natural buffers against coastal hazards…”.
DLNR-OCCL completed a statewide programmatic environmental assessment and is in
the process of updating its permitting program for Small Scale Beach Restoration.
The Division of Aquatic Resources is developing the Coral Reef Restoration Action Plan.
This plan will designate specific areas throughout Hawai`i to prioritize long-term coral
reef restoration efforts to address specific goals. One of these goals is shoreline
protection. The State will rely on community input, intersections between coral reef
health and economic valuations of coastal flood risk/hazard mitigation potential, andanalyses of vulnerable coastal infrastructure as likely factors in deciding specific sites forshoreline protection focused coral reef restoration.
The Hawai`i Department of Transportation (HDOT) published the Statewide Coastal
Highway Program Report in 2019. The objective of the project was to develop ascientifically rigorous methodology to assess and rank the susceptibility of State of
Hawaii coastal roads to erosion and structural degradation due to ocean hazards such as
waves, currents, tides and sea level rise.
HDOT’s Act 100 Resiliency Report outlines the work HDOT is performing to incorporate
resilience into its programs and projects.
Ko`olauloa Sustainable Community Plan includes the following: “To the extent possible,
acquire shallow developed beach-front lots which would be impractical to redevelop
given existing zoning standards or wave hazard considerations in order to improve
public access and lateral shoreline views along Kamehameha Highway”.
DHHL's draft So. Molokai Shoreline Erosion Management Plan (SM_SEMP), currently
under review, assesses causes, identifies effective and sustainable shoreline erosion
management strategies, and educates homestead communities on best practices andnature-based solutions. The SM-SEMP will enable DHHL to develop shoreline protection,conservation and restoration priorities and guidelines and work with its lessees toproactively plan for and better manage and mitigate sea level rise-related impacts.
13

o

o

County of Maui Department of Parks and Recreation published the Maui Beach Park
Vulnerability and Adaptation Study with shoreline adaptation strategies for 65 beachparks.
The West Maui Community Plan includes goal 2.1.5 | Protect the shoreline and beaches
by preserving waterfront land within the SLR-XA as open space wherever possible.

● 2.1 Evaluate existing policies and institutional capacity of implementing smart redevelopmentoooAct 208, SLH2022 expands the purpose and rationale for Special Improvement Districts
to include financing of climate change and sea level rise adaptation.
City & County of Honolulu Office of Climate Change and Resilience was established in
the City Charter in 2017 increasing institutional capacity for coordinating actions andpolicies to improve community resilience to climate change and sea level rise impacts
and integrating sustainable and environmental values into City plans, programs, andpolicies.
County of Maui established an Office of Climate Change, Resiliency, and Sustainability in
2022 to increase capacity including through the ongoing development of a Climate
Action and Resiliency Plan and Resilient Housing Guide.

● 2.2 Identify priority areas for smart redevelopment as part of a managed retreat strategyoWest Kaua`i Community Plan (adopted 2020) includes Objectives (page 65) to provide ahigher elevation area for property owners with vulnerable homes to retreat to in the
future via transfer of development rights or land swap opportunities and that evacuatedland serves as a buffer against future coastal hazards.

● 2.3 Conduct a market study for priority redevelopment areasoNo known progress.

● 2.4 Develop detailed redevelopment strategies for priority areas and incentivize development

West Kaua`i Community Plan (adopted 2020) includes an Objective (page 65) to Support
a master-planned new community mauka within a Walkable Neighborhood designationto accommodate workforce housing, planned growth, and a potential sea level risemanaged retreat area.
o The Waimea 400 Master Plan incorporates considerations of flooding and sea level risein land use planning.
o● 2.5 Update capital improvement planning to incorporate sea level rise and prioritize
infrastructure improvements for priority redevelopment areas14

o

Act 178, SLH2021 requires OPSD, in cooperation with each state agency having
operational responsibilities over state facilities, to identify existing and planned facilities
that are vulnerable to sea level rise, flooding impacts, and natural hazards; assess arange of options to mitigate the impacts of sea level rise to those facilities. OPSD-CZM
maintains a Story Map titled Sea Level Rise Adaptation in Hawai`i to track progress on
meeting the Act 178 mandate.

● 2.6 Develop design standards for existing and proposed land uses that limits urban growth andincreases flood resiliency within the SLR-XA
o Act 16, SLH2020 amended HRS § 205A-44 to ensure that permitted structures within the
shoreline setback may not be rebuilt or replaced without a new variance. Specifically, it
states that “permitted structures may be repaired, but shall not be enlarged, rebuilt, or
replaced within the shoreline area without a variance.”o City and County of Honolulu released Climate Adaptation Design Principles identifying
recommended tools and best practices to consider in designing building sites andstructures to be resilient to sea level rise, flooding, extreme heat, and groundwater
inundation.
o In October 2022, County of Kaua`i passed first of its kind Sea Level Rise Constraint
District that uses passive flooding and wave runup models developed for Hawai`i Sea
Level Rise Viewer. Using these modeled sea level rise hazards, the constraint district
requires the elevation of at least two feet out of harm’s way for residential structures
and at least one foot out of harm’s way for non-residential structures to limit the risk topublic health and safety. The constraint district is a great example of resilient design
standards for proposed uses within the SLR-XA.

● 2.7 Require the design and siting of planned new development and capital improvement●

projects to include an in-depth analysis of sea level rise impacts based on elevation, tolerance
for risk, and lifetime of the structureo The State Environmental Impact Statement Rules (HAR 11-200.1) were updated in 2018
to include consideration of location in the sea level rise exposure area in determining
whether an action may have a significant effect on the environment. Environmental
Impact Statements and Environmental Assessments must include SLR-XA maps as anindication of impact on the environment.
o The 2018 Kaua‘i General Plan Policy 3.2C1 States: “In accordance with Hawai‘i State
Planning Act Priority Guidelines, consider multiple scenarios of SLR and associatedflooding, wave inundation, and erosion impacts when developing and approving capital
improvement projects.”
2.8 Develop State and County guidance and a checklist for developers to assist with the
integration of sea level rise in project design and encourage the use of best management
practices for incorporating green and sustainable approaches in all stages of project
development.
o City and County of Honolulu released Climate Adaptation Design Principles identifying
recommended tools and best practices to consider in designing building sites andstructures to be resilient to sea level rise, flooding, extreme heat, and groundwater
inundation.

15

● 2.9 Develop guidance on integrating sea level rise and climate change in the environmental

review process and incorporating environmental justice considerations
o Act 17,SLH2018 directed the environmental council to adopt and maintain rules
pursuant to chapter 91, Hawai`i Revised Statutes, requiring all environmental
assessments and environmental impact statements prepared pursuant to chapter 343,
Hawai`i Revised Statutes, whether in draft or final form, to include consideration of sea
level rise based upon the best available scientific data regarding sea level rise.
Subsequent rules amendments incorporated the requirement.
o In November, 2019 the State Climate Commission released a Statement on Climate
Equity which urges government entities in Hawai`i to Use a vulnerability framework thatis appropriate for Hawai`i, and incorporate cultural responsiveness, reflect indigenous
voices and customary law practices to identify any inequitable distribution of benefits,burdens and processes caused by climate change impacts and policy; and - Recognize
and address the inequitable distribution of benefits, burdens and processes, byincorporating equity considerations into their planning, policy development andimplementation for climate change mitigation, adaptation and resilience. For
adaptation policies relating to sea level rise, such a framework should address equity
issues surrounding access to information in the identification and prioritization ofaddressing the impacts of sea level rise on critical public infrastructure—such as roads,
bridges, schools, hospitals, shelters and other structures. It poses the question: Howwill Hawaii’s vulnerable communities provide input into policymaking that addresses theimpacts of sea level rise?
o The State Environmental Impact Statement Rules (HAR 11-200.1) were updated in 2018
to include consideration of location in the sea level rise exposure area in determining
whether an action may have a significant effect on the environment. Environmental
Impact Statements and Environmental Assessments must include SLR-XA maps as anindication of impact on the environment.
o CZM’s NOAA Coastal Fellow began her 2-year fellowship on August 1, 2022. The Fellow’s
project focuses on the nexus of coastal hazards and social vulnerability in Hawai`i andaims to better understand and identify communities with higher risk to coastal hazards
due to socio-economic and demographic factors.

● 2.10 Integrate sea level rise vulnerability considerations into the Hawaiʻi Coastal Zone

Management (CZM) Act
o Act 16, SLH2020 amended the Hawai`i Coastal Zone Management Act (HRS Chapter
205A) to further protect against impacts of sea level rise including adding sea level risein the definition of “coastal hazards.”
o Act 16, SLH2020 amended the Hawai`i Coastal Zone Management Act (HRS Chapter
205A) to further protect beaches by increasing the minimum shoreline setback in eachcounty from 20 to 40 feet. Specifically, the legislature amended HRS § 205A-43 to
mandate that shoreline setbacks throughout the state be “not less than forty feet inlandfrom the shoreline.”o County of Maui and County of Kaua`i amended their shoreline setback ordinances toinclude a historical erosion rate-based setback. Updates are pending with the City andCounty of Honolulu, would update Revised Ordinances of Honolulu Chapter 23, relatingto Shoreline Setbacks, to incorporate the 2020 CZMA amendments and implement ahistorical erosion-based shoreline setback formula on Oʻahu (Bill 41, 2022).
16

Amendments to the Maui County ordinance to utilize a model-based erosion hazard line
as the baseline for setbacks are pending.

● 3.1 Adopt higher flood standards to account for sea level riseoo

The State of Hawai`i 2018 Hazard Mitigation Plan incorporated the results of modelingand an assessment of vulnerability to coastal flooding from storm-induced wave eventswith sea level rise. A 1%-annual-chance coastal flood zone with 3.2 feet of sea level rise
was modeled to estimate coastal flood extents for wave-generating events including
tropical storms, hurricanes, tsunamis, and other severe wave events with sea level rise
and was added to the Hawai`i Sea Level Rise Viewer.
County of Kaua`i adopted Bill 2879 to update the zoning ordinance to require the lowest
floor of any new dwellings in the Sea Level Rise Constraint District be raised 2 feet above
the highest sea level rise flood elevation as projected by the SLR-XA Viewer andassociated Kaua`i SLR Constraint District Viewer. New, non-livable buildings need to beraised 1 foot above the flood elevation projection.

● 3.2 Consider adopting V zone construction standards in the Coastal A ZoneoNo known action.

● 3.3 Provide technical and financial support to a state-wide Community Rating System programoooNo known state-wide action
County of Maui and County of Hawai`i are active Community Rating System (CRS)
communities. Currently, flood insurance policy holders in the County of Maui benefit
from a 15 percent reduction in their NFIP premiums due to Maui’s proactive flood risk
reduction measures. Residents of the County of Hawai`i already receive 10 percent
reductions.
County of Kauaii’s status as an active CRS community is pending, an official
announcement is expected in 2023

● 3.4 Encourage property owners at risk to coastal flooding to purchase flood insurance

DLNR, FEMA and Hawai`i Independent Insurance Agents hosted a continuing education
seminar on the National Flood Insurance Program (NFIP) for licensed insurance agents inAugust 2019.
o The City and County of Honolulu Office of Climate Change, Sustainability and Resiliency
provides information flood risk and flood insurance on their Get Flood Ready website.
● 3.5 Incorporate sea level rise into state and county hazard mitigation plans
o

17

o
o
o
o
o

The State of Hawai`i 2018 Hazard Mitigation Plan included expanded risk andvulnerability assessment for Climate Change and Sea Level Rise utilizing the SLR-XA datafrom the 2017 Report and Viewer.
The 2020 Multi-Hazard Pre-Disaster Mitigation Plan for the City and County of Honolulu
incorporates Climate Change, Sea Level Rise and coastal erosion into the vulnerability
and mitigation planning.
The 2020 County of Maui Hazard Mitigation Plan Update incorporates Climate Change,
Sea Level Rise and coastal erosion into vulnerability and mitigation planning.
The 2020 County of Hawai`i Multi-Hazard Mitigation Plan recognizes Climate Change,
Sea Level Rise and coastal erosion into vulnerability and mitigation planning.
The 2020 County of Kaua`i County Multi-Hazard Mitigation and Resilience Plan
incorporates Climate Change, Sea Level Rise and coastal erosion into vulnerability andmitigation planning.

● 3.6 Adopt a state-wide program that supports the Building Code Effectiveness Grading Schedule(
BCEGS) program for insurance ratingo HI-EMA conducting surveys of BCEGS eligibility ratings for each county - recently
assessed Kaua`i County with a rating of 9, and currently assessing Big Island.

● 3.7 Develop pre-disaster recovery frameworks at state and county levels that incorporate

opportunities to adapt to sea level rise through disaster recovery
o HI-EMA’s 2020-2025 Five Year Strategic Plan recognizes development of disasterrecovery frameworks as a key element in meeting preparedness goals.
o Honolulu Office of Climate Change, Sustainability, and Resilience has a current grantfunded project to develop a Long-Term Disaster Recovery plan and tools to help O`ahu
organize and recover more quickly from a disaster.
o Hawai`i Sea Grant is in receipt of grant funding to assist County of Kaua`i develop a predisaster recovery plan beginning in 2023.

● 3.8 Perform a study to identify what other incentives could be utilized to promote improved
flood risk management.
o No known action.

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● 4.1 Conduct a state-wide assessment to identify legacy beach conservation priorities
o

o

o
o

Act 16, SLH 2020 updated the Hawai`i Coastal Zone Management Act (HRS Chapter
205A), including strengthening protections for beach and other coastal environments
and prohibitions against seawalls and other coastal armoring.
OPSD-CZM is conducting a Regional Shoreline Management Scoping Study (ongoing) todevelop and outline a recommended approach that can help define regions andsubregions for the purpose of improving shoreline management. The Scoping Study will
explore strategies for utilizing environmental characteristics and conditions to define“regions” for the purposes of rethinking shoreline management across the state, with
the intention of facilitating larger-scale, nature-based, comprehensive management
strategies.
DLNR-OCCL completed an statewide programmatic environmental assessment and is in
the process of updating its permitting program for Small Scale Beach Restoration.
The City and County of Honolulu adopted Ordinance 22-22 Relating to Indigenous Plants
in Public Beach Parks prioritizing the use of appropriate indigenous plantings toenhance the health of beaches and dunes and enhance resilience.

● 4.2 Establish a “willing seller” program to move development away from legacy beachesoOPSD-CZM published a report titled Assessing the Feasibility and Implications ofManaged Retreat Strategies for Vulnerable Coastal Areas in Hawai`i in 2019 and isembarking on a next-step study that will assess the options for and implications of
implementing managed retreat from the perspectives of (1) policy and regulation and(2) funding and financing mechanisms.in 2023.

● 4.3 Amend the State Legacy Lands Act to set aside funding for priority coastal lands and enable

the use of a variety of practices and toolso Legislation to amend the State Legacy Lands Act was considered but determined not tobe the best mechanism for designating funds for coastal land acquisition. An update tothis Recommended Action is detailed later in this report.

● 4.4 Expand the area of national, state, and county parks and wildlife refuges to preserve criticalcoastal wildlife habitatso No known action.

● 4.5 Prioritize coral reef preservation to buffer the impacts of coastal hazards with sea level riseo

In 2021 SCR159, SD1 directed the following: “Department of Land and Natural
Resources is urged to examine and consider purchasing reef insurance to support
nature-based solutions to protect Hawaii's coastline and coastal infrastructure fromnatural disasters.”. The Division of Aquatic Resources found reef insurance to be a19

valuable financial tool because of its accessibility to both public and private sector funds
and its ability to rapidly deploy money for reef resilience maintenance via emergency
restoration. They also encouraged continued investigations into additional funding
sources, as this is not the only financial tool for hazard mitigation utilizing nature-based
solutions. Additional findings related to coral reef’s role in coastal protection and sea
level rise mitigation can be found in the Division of Aquatic Resource’s Reef Insurance
Feasibility Report.

● 4.6 Develop public-private partnerships for coastal land acquisition, beach management, andreef protection
o Act 208, SLH2022 expanded the purpose and rationale for Special Improvement
Districts to include financing of climate change and sea level rise adaptation.
o Hawai`i Sea Grant published the Hawai`i Dune Restoration Manual in 2022. The manualis a resource for community groups, nonprofits, county and state agencies anddepartments, coastal resorts and condominiums, coastal landowners and managers, andanyone interested in conducting proactive dune restoration projects in partnership with
Hawaiʻi Sea Grant community extension agents.

● 5.1 Develop an archipelagic-wide inventory of Native Hawaiian cultural resources and practices

impacted by sea level riseo OHA’s Kipuka Database is a geographical information system (GIS) that utilizes the latest
mapping technologies to provide a window into native Hawaiian land, culture andhistory. Kipuka links historic data sets to geographic locations reinforcing the concept of
information embedded in the ‘aina (land), encoded in the wahi inoa (place name). The
foundation of Kipuka is the traditional land system, mokupuni divided into moku,
ahupua‘a, ili and kuleana. The mission of Kipuka is to create a repository of knowledge
where information about Hawai‘i’s land, culture and history can be easily accessed, todevelop a virtual mo‘oku‘auhau of land tenure in Hawai‘i, and to provide an opportunity
for individuals to forge new relationships between themselves and the ‘aina (land) thatis most important to them.

● 5.2 Work with Native Hawaiian Communities to develop a culturally-based adaptation process

and protocols to preserve iwi kūpuna and Native Hawaiian cultural resources and practices withsea level riseo The County of Kauai`i is engaged in developing an island-wide Climate Adaptation Plan.

● 5.3 Develop adaptation plans to preserve access to coastal lands and water within Native
Hawaiian communities with sea level rise.
o No known action.

20

● 6.1 Identify hazard mitigation measures to address coastal flooding of hazardous material/waste
storage facilities, underground storage tanks, and on site sewage disposal systems vulnerable tosea level riseo Hawai`i Department of Health, Hazard Evaluation & Emergency Response Officereleased a memorandum in June 2021 describing how increased flooding, groundwater
inundation and sea level rise resulting from climate change will increase risks to humanhealth and the environment from chemical contamination.
o There are currently over 88,000 cesspools in Hawai`i and many of them are in theSpecial Management Area and located on beachfront properties. State has banned theconstruction of new cesspools and has required that all current cesspools be converted
by 2050. Act 125, SLH2017 requires conversion of cesspools by 2050. Act 153, SLH2022
authorized development of a pilot program to assist low- and middle-income residents
to complete the conversion.
o A state income tax credit is available for upgrading a cesspool to a septic or aerobic
system or connecting to the sewer for cesspools located within 500 ft of the shoreline, aperennial stream or wetland, or within a source water assessment program area.
o The Department of Health (DOH) has been authorized by Act 132, SLH2018 to establish
a cesspool conversion working group. The purpose of this working group is to develop a
long-range, comprehensive plan for cesspool conversion statewide for all cesspools by
2050. The final report of the working group is due to the legislature prior to the 2023
session.
o During FFY 2022 approximately $12.3 million under the Base Clean Water State
Revolving Fund (CWSRF) appropriation and $14.5 million under the Bipartisan
Infrastructure Law (BIL) CWSRF appropriation will be allocated to the State of
Hawai`i. The DOH Wastewater Branch is now prioritizing funding of wastewater projects
that will support sustainable infrastructure to withstand the effects of rising Sea level
due to climate change and provide adaptation for coastline innovation.

● 6.2 Review existing environmental regulations, guidance documents, and best management
practiceso No known action.

● 6.3 Update guidance and propose legislative amendments to existing environmental regulations.
oNo known action.

21

● 7.1 Conduct more detailed financial and economic analysis of sea level rise impacts in the SLRXAoNo known action.

● 7.2 Develop a multi-pronged financing strategy at federal, state, county, private sector, andphilanthropic levels to address costs of adaptation to sea level riseo Act 208, SLH2022 expands the purpose and rationale for Special Improvement Districts
to include financing of climate change and sea level rise adaptation.

● 7.3 Require mandatory disclosure for private properties and public offerings located in areas

with potential exposure to sea level riseo In 2021, the State of Hawai`i enacted an update to the Mandatory Seller Disclosures inReal Estate Transactions Law, codified within Hawai`i Revised Statutes §508D-15,
requiring that real estate transactions within the State must disclose any risk of sea level
rise (up to and including the 3.2-feel sea level rise scenario) to the property. The
Commission released a flyer regarding the Disclosure Requirement for Residential Real
Estate in the Sea Level Rise Exposure Area in 2022 to assist real estate agents andhomeowners effectively navigate the new law. The promotional materials include
information on how to identify whether a property is at risk, what the potential risks
are, and how to use the Hawai`i Sea Level Rise Viewer.

● 7.4 Explore the use of transfer of development rights and purchase of development rights

programs that facilitate managed retreat and legacy beach preservationo Act 223, SLH2022 expands the authority of the counties to transfer development rights
to address areas at risk of sea level rise, coastal erosion, storm surge, or flooding
associated with climate change.
o Honolulu City Council is considering a bill (Bill 10, 2022) with proposed updates to theLand Use Ordinance relating to transfer of development rights from properties within
the special management area (SMA) to a location outside the SMA is in discussion in theCity Council.

● 7.5 Consider the feasibility of a buy-out program for residential property owners vulnerable tosea level riseo

In February 2019 OPSD-CZM released a report titled Assessing the Feasibility andImplications of Managed Retreat Strategies for Vulnerable Coastal Areas in Hawai`i. The
report determined that at time of writing, it was unrealistic to develop a step-by-stepplan to implement managed retreat areas in Hawai`i threatened by sea level rise, given22

a variety of unknowns and competing priorities. Instead, the assessment reports
findings regarding retreat programs and their relative significance to Hawai`i and a
specific multi-prong recommendation regarding the feasibility of retreat in Hawai`i.

● 8.1 Update coastal hazards modeling and vulnerability assessment as needed based on new
climate science, sea level rise projections, and methodsooooOngoing updates to the modeling for the SLR-XA Viewer are outlined in the Updates tothe 2017 Report and Viewer above and in the Next Steps section at the end of thisReport.
In 2022 HDOT Highway’s released an Asset and Hazard Map that lets users explore theintersection of transportation infrastructures and climate hazards across Hawaii.
In 2021 Pac IOOS released a Wave Runup Tool for West Maui and theWest Maui Wave
Flooding Tool to provide specific information for the region.
County of Maui developed the Maui County Beach Park Vulnerability Tool.

● 8.2 Engage communities in monitoring the impacts of sea level riseoHawai`i Sea Grant sponsors the Hawai`i and Pacific Islands King Tides citizen science
program to enable individuals to contribute to the documentation of the impacts of King
Tides to better understand tomorrow’s impacts from sea-level rise and othercoastal hazards.

● 8.3 Conduct in-depth assessment of vulnerability and evaluation of adaptation strategies forcritical infrastructure throughout the Stateo In 2021, the State’s Thirty-First Legislature recognized that climate change and sea level
rise “pose significant, dangerous and imminent threats to the State’s social andeconomic well-being, public safety, nature and environment, cultural resources,
property, infrastructure, and government functions and will likely have adisproportionate impact on low-income and otherwise vulnerable communities.” Act
178, SLH2021 Relating to Sea Level Rise Adaptation was passed to begin the long-termplanning needed to effectively address climate impacts. The purpose of this Act is to: (1)Require the OPSD, in coordination with state agencies with operational responsibilities
over state facilities, to: a. Identify existing and planned facilities that are vulnerable tosea level rise, flooding impacts, and natural hazards; b. Assess options to mitigate theimpacts of sea level rise to those facilities; and c. Submit annual reports to theGovernor, Legislature, and the Hawai`i Climate Change Mitigation and Adaptation
Commission regarding vulnerability and mitigation assessments for state facilities andprogress toward implementing sea level rise adaptation in future plans, programs, and23

capital improvement needs and decisions. (2) Update and reaffirm the role of the OPSD
to coordinate climate change adaptation and sea level rise adaptation among all stateagencies to improve the interagency coordination of these activities; and (3) Amend the
Hawai`i State Planning Act to include sustainable development, climate change
adaptation, and sea level rise adaptation as objectives for facility systems.
o OPSD-CZM released a 2021 Annual Report for Act 178, SLH2021. The report describes
OPSD’s activities and progress related to the implementation of Act 178, Relating to Sea
Level Rise Adaptation, including a discussion on the findings of an initial state facility
inventory and exposure assessment, considerations for future assessments, andrecommendations for next steps. The report identifies a three phased approach: 1)
conduct a high-level inventory of state facilities vulnerable to sea level rise; 2) conduct avulnerability assessment of facilities in order to prioritize needs; and 3) identify a suiteof mitigation and adaptation strategies for vulnerable facilities.
o OPSD-CZM is developing a Menu of Coastal Hazard Adaptation Strategies Suitable for
Hawai`i Coastlines. The project deliverable is a comprehensive, informational resourcethat outlines potential coastal adaptation strategies. Each strategy will have its own“Strategy Info Card” which highlights the strategy’s pros and cons, appropriate site
conditions, potential permits, etc. The project is scheduled to be completed by
November 2022.
o OPSD-CZM is developing a Regional Shoreline Management Scoping Study. This scoping
study is an exploratory step towards a regional shoreline management strategy for theState of Hawai`i. Current shoreline management is done at the parcel level which often
leads to “harder” adaptation solutions. This study will result in a proposed methodology
for defining “coastal regions and subregions” that considers environmental and land use
factors. The project is scheduled to be completed by December 2022.
o Hawai`i Sea Grant, University of Hawai`i Department of Urban and Regional Planning,
and County of Kaua‘i conducted a 2-year community-based vulnerability assessment forclimate change and sea level rise on West Kaua`i using the decision support tool:
Vulnerability, Consequences, Adaptation, Planning Scenarios or VCAPs. The assessment
covered 6 management concerns and profiled 5 towns. This involved mapping of
exposed community assets, and 7 four-hour workshops with the community. All thecommunity participants combined resulted in over 100 hours sharing important
information on how West Kaua`i is vulnerable to sea level rise, and options foradaptation. The final report was produced in June 2020. The County of Kaua`i
incorporated the results of the WKCVA into the West Kaua`i Community Plan, a land use
and policy document for the west side, which was adopted in 2020.
● 8.4 Develop a sea level rise research, assessment, and monitoring agenda to support the 5-year
update process
o The Climate Resilience Collaborative (CRC) is a research program at the University of
Hawai`i at Mānoa, School of Ocean and Earth Science and Technology, that is fundedthrough the Office of Naval Research and led by Dr. Chip Fletcher. CRC is an affiliationof researchers, technicians, modelers, architects, attorneys, economists, planners, andundergraduate and graduate students spread across the Mānoa campus working onchallenges related to climate change. CRC personnel conduct investigations of sea level
rise and community design, increasing resilience to extreme weather events, projecting
future climate stresses and shocks, marine and reef impacts, and better understanding24

community exposure to rising heat, storms, and drought. This requires cross-disciplinary
and integrated research investigation on a range of spatial and temporal scales.

● 9.1 Develop sea level rise adaptation priorities for the Hawai`i Climate Commissiono

The Hawai`i Climate Commission adopted Recommendations for Countering the Impacts
of Sea Level Rise in September, 2018.

● 9.2 Continue to support the Office of Planning and DLNR-OCCL to provide leadership, technicalsupport, education and outreach, and interagency coordination to the Hawai`i Climate
Commission and other stakeholders for sea level riseo Working closely with the OCCL Administrator, Hawai`i Climate Mitigation and
Adaptation Commission Coordinator, and planning staff at the DLNR-OCCL throughcooperative funding agreements, University of Hawai`i Sea Grant extension specialists
aid the DLNR-OCCL and partner State and county government agencies in making sound,science-based decisions promoting responsible and proactive coastal land use planningand coastal zone management and assist the DLNR with its climate change and sea level
rise adaptation efforts.
o The 2020 Ocean Resources Management Plan: Coastal Zone Management Mauka to
Makai provides guidance for a focused effort to improve State policies for ocean
resources by addressing management gaps in the State. Within the focus area ofDevelopment and Coastal Hazards, the Plan identifies community action opportunities,
main entities in the action team, and recommendations for stakeholders to consult. The
Plan also lists out proposed projects and initiatives addressing this focus area, based on
closing identified management or knowledge gaps. The ORMPʻs Coordinated Working
Group, program managers representing a variety of agencies at the state, county andfederal levels, meet quarterly to exchange information and build collective knowledge.
o OPSD-CZM worked with the USACE to officially establish the Hawai`i Silver Jackets Teamin 2021. The Team’s first initiative, approved in 2022, is to develop a framework for
decision-making along Hawaii’s shorelines. Actions planned through this proposal
include identification of specific decision-making roadblocks and possible resolutions
through 1) review of state and county regulations & 2) proposed revisions to facilitate
consistent land use decisions that ensure the inclusion of current and projectedenvironmental conditions, coastal hazard risks, and types of development. CZM will
collaborate with county planning departments, OCCL, HI-EMA, NOAA OCM and USACE.
The proposal is designed to obtain alignment of agency responses to chronic coastal
hazards and provide homeowners/developers/planners with predictability on what
mitigation strategies are acceptable. The Silver Jackets team acknowledges that this
proposal may not allow for resolved decision-making for all of Hawaii’s diverse coastal25

geologies, hydrodynamics, and development patterns and will work collectively towards
identifying highest priority typologies.

● 9.3 Develop a multi-agency, multi-media, and multi-stakeholder education and outreachprogram as part of a long-term commitment to building an informed and active constituency on
climate change mitigation and adaptationo The Hawai`i Climate Change Portal hosted by the Climate Commission hosts a
consolidated inventory of climate adaptation and mitigation documents and tools.

● 9.4 Develop a monitoring and evaluation plan with benchmarks and indicators to support the 5year update process
o No known action.

Further Recommendations and Next Steps
As we continue to make progress towards achieving the recommendations set forth in the 2017 Report,
we must also focus on realigning our path and goals to continue to progress over the next five years.
This includes proposing updated recommendations to guide State and County Agencies in continued
planning and implementation of sea level rise related adaptation and mitigation efforts, as well as
identification of new and unmet needs. Together, the updated recommendations and identification of
unmet needs present a roadmap for bridging to a next-generation State of Hawai`i Sea Level Rise Viewer
and a comprehensive update to the Hawai`i Sea Level Rise Vulnerability and Adaptation Report in five
years.

Recommendations
The accomplishments achieved since 2017 provide a solid foundation for continued action for the state
to meet the challenges and impacts of sea level rise. All 2017 recommendations and recommended
actions should be continued over the next five years, with some minor edits and additions as outlined
below. This report includes new recommended actions that align with existing recommendations fromthe 2017 Report and updates to some 2017 recommended actions.
This section presents the following:●●●

Two new recommendations, labeled as 2022 Recommendations, with associatedRecommended Actions, labeled as 2022 Recommended Actions,
One updated 2017 Recommendation, labeled as Updated 2017 Recommendation with threeassociated updated 2017 Recommended Actions, labeled as Updated 2017 Recommended
Actions, andThirteen new Recommended Actions aligned with 2017 Recommendations, labeled as 2022
Recommended Actions.

2022 Recommendation 1: Conduct a full update of the Sea Level Rise Vulnerability and Adaptation
Report in 2027.
● 2022 Recommended Action 1.1: Develop a next-generation State of Hawai`i Sea Level Rise
Viewer and complete a more extensive update of the Hawai`i Sea Level Rise Vulnerability and
Adaptation Report in 2027 utilizing the latest and best-available climate change and sea level rise
26

●

●

●

scientific information and sea level rise exposure map data (e.g., Climate Resilience Collaborativeat the University of Hawai`i). The state should allocate funding to complete a comprehensive
report in 2027 with a focus on community-level impacts and actions and implementation ofidentified adaptation recommendations from 2017. This recommendation builds on the existingmandate for a review and update every five years by proposing that the 2027 Report include afull vulnerability assessment and documentation of ongoing initiatives to reduce vulnerability andincrease resiliency and adaptation. Contracting and drafting for the 2027 Report should begin atleast two years in advance of the reporting deadline mandated by Act 32, SLH2017. Current
progress towards developing the next-generation Sea Level Rise Viewer is detailed in the Next
Steps Section, below.
2022 Recommended Action 1.2: Develop a centralized tracking system to coordinate all efforts
that are responsive to the 2017 and 2022 Report Recommendations. Establish a position within
DLNR, in coordination with the Climate Commission, to improve cooperation and coordination
between State and county agencies for all issues relating to sea level rise mitigation andadaptation, and to raise the visibility and understanding of these efforts to the public and acrossthe state and county government agencies. The state should create a reporting tool potentiallyhoused by the State Climate Commission, to consolidate reporting of progress towards meetingthe objectives and recommendations of the 2017 Report and this Update. Ongoing accounting
for the initiatives and progress from state and county agencies will enable greater visibility
between agencies and will support the completion of the 2027 Report. This Recommended
Action also aligns with 2017 Recommended Action 9.4 Develop a monitoring and evaluation planwith benchmarks and indicators to support the 5-year update process.
2022 Recommended Action 1.3: Identify emerging issues and unmet needs for sea level rise
adaptation and mitigation not addressed by the 2017 Report. State and county agencies, incoordination through the State Climate Change Commission, should review current and ongoing
initiatives to determine unaddressed issues for consideration in the 2027 Report.
2022 Recommended Action 1.4: Conduct an updated and more detailed vulnerability assessment
within the SLR-XA: As part of the 10-Year Update the state should conduct a full review of allactions taken in response to these recommendations and the 2017 recommendations todetermine the changes in vulnerability within the SLR-XA as a factor of exposure, sensitivity, andadaptive capacity. The vulnerability assessment should include a detailed analysis of socioeconomic factors including community sensitivity and adaptive capacity.

2022 Recommendation 2: Continue to implement the 2017 Recommendations with minor edits asoutlined in the 2022 Report Update.
● 2022 Recommended Action 2.1: Identify gaps in progress since 2017. State agencies should
work towards completing and where necessary, revising the recommendations from the 2017
Report with a particular focus on areas where significant progress is lacking in the past five
years. The state should ensure that agencies are adequately resourced to implement programs
and policies to address the increased risk of sea level rise.
2017 Recommendation 1: Support sustainable and resilient land use and community development● Updated 2017 Recommended Action 1.1: Recognize the SLR-XA as a statewide exposure zone:
The phrase “vulnerability zone” should be replaced with “exposure zone” to more accurately
27

●

●

●

reflect what the SLR-XA depicts. Vulnerability within the exposure area can be reduced throughadaptation measures for infrastructure that cannot be moved. Although all infrastructure
within the SLR-XA is vulnerable to sea level rise, several factors can impact the extent ofvulnerability or resiliency.
2022 Recommended Action 1.7: Update planning guidance to reflect most recent sea level rise
projections:
Following the latest Sweet, et al., 2022 NOAA-interagency sea level rise report, the state should
set a revised planning and policy benchmark of 4 ft as the minimum scenario for all planning anddesign based on the report’s Intermediate (mid-range) scenario for Hawai`i of 3.9 feet of sea
level rise by 2100, and apply a 6 ft benchmark for planning and design of public infrastructure
projects and other projects with low tolerance for risk based on the report’s Intermediate Highscenario for Hawai`i of 5.9 feet of sea level rise by 2100. The latest science suggests that the
SLR-XA for 3.2ft of sea level remains valid as a planning overlay for the mid century at this time.
The State should continue to use the 3.2 foot Sea Level Rise Exposure (SLR-XA) and NOAA 6 footpassive flooding map data available in the Viewer until updated SLR-XA data is available.
Agencies should incorporate the revised planning benchmarks into adaptation planning toaccount for the more accurate regional projections prior to the availability of revised SLR-XA
data as possible. This recommendation is consistent with recent recommendations from theCity and County of Honolulu Climate Change Commission which recommends an increase from
3.2 feet of sea level rise by 2100.
2022 Recommended Action 1.8: Implement the recommendations of the February 2019 Officeof Planning and Sustainable Development - Coastal Zone Management Program report titled“Assessing the Feasibility and Implications of Managed Retreat Strategies for Vulnerable Coastal
Areas in Hawai`i”: The state should establish and fund programs at the state and county level toincentivize relocation (e.g., willing-seller managed retreat) to benefit community resilience andprotect public trust resources. Such programs include the ongoing work to:○ Expand the State’s and counties’ ability to implement voluntary managed retreat “tools”
including but not limited to transfer of development rights (TDRs), rolling easements,and land transfers;○ Review state and county land use to determine where it may be possible to retreat to,i.e, “receiving areas”;○ Engage communities to obtain their input and priorities for retreat location strategies;○ Identify and establish federal, state, and county funding for retreat and restoration ofcoastal lands to natural conditions or lightly developed parklands for public benefit ofconserving shoreline access and improving community resilience;○ Review state and county plans to determine where they may be amended and updated
to support retreat;○ Review laws and regulations that may have to be amended and adopted to facilitate
retreat;○ Prioritize support for voluntary relocation of multi-generational shorefront landowners;and○ Establish managed retreat pilot implementation areas.
2022 Recommended Action 1.9: Conduct long-term strategic planning for maintenance, repair
and replacement of critical infrastructure within the SLR-XA in advance of emergent need: State28

agencies should undertake long-term strategic planning initiatives to reduce the use of
emergency measures for maintenance and repair of facilities and infrastructure within the SLRXA. Emergency authorizations and implementation of adaptation measures reduce public input
to the planning and permitting process. While immediate emergency action is sometimes
necessary for public health and safety, it should not be used to circumvent public involvement.
Proactive and comprehensive long-term planning for sea level rise impacts prior to emergency
situations is necessary to safeguard natural resources while ensuring ongoing maintenance andpotentially relocation of critical infrastructure. Accurate SLR-XA data available via the Viewer
provides an advanced look at future sea level conditions and is a key planning tool for applying
planning benchmarks outlined in this report.
2017 Recommendation 2: Prioritize smart urban redevelopment outside the SLR-XA and limit
exposure within the SLR-XA●

2022 Recommended Action 2.10.1 Incorporate existing and emerging scientific data in updates
to shoreline setback ordinances: The state should support the counties in updating shoreline
setback and zoning ordinances to reflect the increasing threat of coastal erosion and sea levelrise.

2017 Recommendation 3: Incentivize improved flood risk management; Recommended Action 3.1
Adopt higher flood standards to account for sea level rise●●2022 Recommended Action 3.1.1: Improve guidelines and regulations for planning and designin the SLR-XA and FEMA Special Flood Hazard Zones: Establish a position within DLNR, in
coordination with the Climate Commission, to improve cooperation and coordination between
State and county floodplain management and planning departments to integrate sea level rise
considerations into floodplain management and hazard mitigation.
2022 Recommended Action 3.1.2 Utilize passive flooding and wave runup model projections inbuilding and zoning ordinances (e.g., “Constraint District”): The state should support counties in
updating zoning ordinances and building codes to incorporate model projections of passive
flooding and wave runup.

Updated 2017 Recommendation 4: Enable legacy beaches to persist with sea level rise;●●

Updated 2017 Recommended Action 4.1: Conduct a state-wide assessment of beaches applying
the objectives of the Hawai`i Coastal Zone Management Act (HRS §205A-2). The DLNR, Office ofConservation and Coastal Lands (OCCL), together with federal, state, and county governments,
nongovernmental organizations, and local stakeholders, should undertake a state-wide
assessment to identify beaches and dune systems that are important for recreational uses,
cultural practices, wildlife habitat, and coastal resilience. The state should further coordinate
with county agencies to prohibit development in such areas, and even consider removing
development from areas with upland sand deposits if we hope to retain this vital natural andcultural resource for future generations.
Updated 2017 Recommended Action 4.2: Establish a “willing seller” program to movedevelopment away from beaches: The State should establish a “willing seller” program that preidentifies property owners that would be willing to sell or relocate their property outside of the
29

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●

state-wide vulnerability zone. There are many successful examples of “willing seller” programs,
the most notable of which is the City of Portland, Oregon’s “Johnson Creek Willing Seller
Program” which helps move people and property out of areas that frequently flood. Restoration
projects on land acquired through the program increase flood storage, improve fish and wildlife
habitat, restore wetlands, and create passive recreational activities for city residents. For more
information regarding this program, please visit
https://www.portlandoregon.gov/bes/article/106234.
Updated 2017 Recommended Action 4.3: Explore legislative and policy mechanisms to designate
funding for priority coastal lands and enable the use of a variety of practices and tools andutilize existing programs to acquire beaches and other coastal lands for recreational, cultural,
ecosystem and resilience objectives: The state and counties should consider additional
legislative actions to identify a dedicated sources of funding for coastal land acquisition. The
state should further pursue opportunities to leverage programs such as the Federal Coastal andEstuarine Land Conservation Program, as detailed in the Hawai`i Coastal and Estuarine Land
Conservation Plan, and other federal or state land acquisition grant programs as they become
available to acquire coastal property for conservation purposes. In addition to land acquisition
for beaches, a variety of tools, including buffer zones and conservation easements, are needed
to support conservation of coastal lands through incremental changes in the shoreline. Bufferzones could be used to restrict development within specified distances of natural and cultural
resources. Expanding buffer zones around beaches, sand dunes, and coastal wetlands would
provide space for these environments to migrate landward with rising sea levels. State law
authorizes public bodies and nonprofit organizations to hold conservation easements for the
purposes of preserving and protecting open space, natural landscapes, cultural and historicalsites and resources, and agricultural lands.
2022 Recommended Action 4.4: Support County Parks Departments in the management ofcounty beach parks. The State should coordinate closely with the County Parks Departments toensure that beach parks are managed holistically and with natural resource protection as a key
priority. Beach Parks present the best opportunity for the preservation of public access andconservation of natural shorelines and beach habitat.

2017 Recommendation 6: Protect nearshore water quality from sea level rise impacts●

2022 Recommended Action 6.1.1: Support research and development efforts to identify andimplement affordable alternatives to cesspools in shoreline areas: Following on the outcomesof the cesspool conversion working group, the state should sponsor research and development
efforts to expand affordable and actionable conversion options for shoreline property owners.
Such options should account for SLR-XA projections of coastal erosion and associated land loss,
and potential failure of onsite sewage treatment systems resulting from SLR-induced
groundwater inundation. Removal of cesspools is imperative to the health of nearshore waters
for all properties within the SLR-XA and for members of the public accessing coastal resources.
Removal may not be achievable by 2050 as directed by state law without viable alternatives for
replacement.

●

2022 Recommended Action 6.4: Develop clear policy and guidance for onsite sewage disposal
systems in the sea level rise exposure area to protect public health: The state should expand
policy directives beyond the existing income tax credits and requirement for removal by 2050.
Specifically, policy must address existing cesspools in the coastal zone in relation to30

enforcement of existing laws and regulations and removal of unpermitted shoreline hardening.
Cesspools on the shoreline and in the coastal zone will be an increasing source of nonpointsource pollution as groundwater rises and coastal erosion accelerates. Applicable to
Recommendation 6.1.

Recommendation 7: Develop innovative and sustainable financing and incentives to support
adaptation to sea level rise●2022 Recommended Action 7.6: Explore the use of the FEMA funding for use in Hawai`i: The
state should explore FEMA funding options to support moving homeowners away from floodzones in support of a comprehensive managed retreat plan. Specifically work with FEMA for
Building Resilient Infrastructure and Communities (BRIC) grants, hazard mitigation programs andother funding opportunities to identify options for federal support to Hawaii’s adaptation
priorities. Additionally, the state should work with federal representatives to explore
exemptions from prohibitive FEMA policies, particularly on DHHL Land where the lessee model
may prohibit individuals from participating in the National Flood Insurance Program (NFIP).

2017 Recommendation 9: Promote collaboration and accountability for adapting to sea level rise●●●2022 Recommended Action 9.5: Incorporate community-scale vulnerability assessments andadaptation planning into the 2027 Sea Level Rise Vulnerability and Adaptation Report. The stateshould develop detailed and comprehensive community-based climate change and sea level risevulnerability assessments and adaptation strategies that prioritize areas experiencing the mostimmediate and severe impacts with early and continuous community engagement and input.
2022 Recommended Action 9.6: Improve cooperation between state and county government
agencies to strengthen enforcement and compliance with existing coastal laws The state should
encourage and support its agencies to cooperate across jurisdictional frameworks and with thecounties’ various agencies to manage coastal resources. The state should encourage progessive
action by its agencies to enforce coastal conservation laws and public and private compliancewith coastal conservation laws. For county agencies that have conducted vulnerability
assessments for their sectors, the state should review the assessments for consistency andconsolidate them to comprehensively visualize and track vulnerabilities across the state.
2022 Recommended Action 9.7: Increase state agency capacity to enforce existing laws andregulations. The state should prioritize enforcement and compliance for natural resource
protection by increasing staffing in regulatory, legal and enforcement agencies.

Next StepsAs an immediate next step, the State Climate Commission should adopt this report and forward it to theLegislature.
In addition to the recommendations listed above, the process of preparing this report has identified thefollowing unmet needs and areas in need of focus in the next five years.

31

○

○
○
○
○
○
○

Facilitate interagency coordination for holistic adaptation planning (e.g.,comprehensive consideration and planning for natural resources, roads, communities;
and improved communications between government agencies) (2017 Recommendation
9, 2022 Recommendation 1)
Conserve and adapt Native Hawaiian cultural resources and sites (2017
Recommendation 5)
Integrate equity and justice considerations to vulnerability assessments andadaptation planning and actions (2017 Recommendation 2)
Address and stop the loss of shoreline access (2017 Recommendation 4)
Integrate economic valuation and ecosystem co benefits of natural coastal resources
into planning and actions (2017 Recommendations 4, 5 and 8)
Make managed retreat a viable option and identify funding mechanisms foradaptation (2017 Recommendations 2 and 7)
Implement phased adaptation to sea level rise (2017 Recommendation 1, 2, 7)

The Climate Commission should set these unmet needs as priority action areas from 2023-2027. To
facilitate coordination among state agencies, the Commission should host a staff-level workshop or
series of workshops for discussion of this report and the actions for each agency going forward. Such aworkshop will set the agenda for the next five years, create a mechanism to ensure ongoing interagency
collaboration, and provide a baseline for action.

Next Steps for the SLR Viewer
To increase our ability to plan for sea level rise The Climate Resilience Collaborative at the University of
Hawai`i is working to update and expand the State of Hawai`i Sea Level Rise Viewer. Utilizing federal
funding, researchers are developing the next generation of passive flooding, high wave flooding, coastal
erosion, compound events and other relevant sea level rise exposure map data that will be available inthree to five years. Specific elements of the work towards as Sea Level Rise Viewer 2.0 are as follow:●●

Augment existing imagery database and increase spatial and temporal resolution of coastline
observations by incorporating imagery from satellites and small unmanned aerial systems (sUASor drones). This will allow for enhanced detail in analyses and modeling. Calculating historicalrates of shoreline change with increased precision will improve future predictions of shoreline
locations.
The USGS-developed Coastal Storm Modeling System - Coastal On-line Assimilated Simulation
Tool (CoSMos-COASTS) is being adapted to Hawai`i-specific wave conditions, and future sea
level rise projections to emulate how the ocean behaves in the near shore environment in two
directions – along-shore and cross-shore to expand on the existing SLR-XA modeling.
○ Development of a full transect grid along the islands’ coastlines, including digitizing theshoreline and identifying non-erodible areas, as well as correctly classifying beach types
and littoral cell boundaries for the CoSMos-COASTS model. This team is also working to
set up the framework for collecting LandSat, Sentinel, and Planet Labs satellite imagery
through the CoastSat package, written by Kilian Vos (UNSW).
○ Collecting aerial imagery and modeling the Island of Oʻahu in phases. Orthomosaics
have been generated for some areas in the islands, the shoreline positions have been32

digitized and beach width determined, and historical and future shoreline change rates
and hazard zones have been produced. Finally, aerial surveys are being conducted of all
the shorelines.
The current SLR viewer has given the state of Hawai`i an opportunity to look ahead and understand therisks of sea level rise well into the future. In a collaborative effort, this new research will help to provide
improved estimates of future shoreline positions for all beaches in Hawai`i with increased spatial andtemporal accuracy. Ultimately, these predicted shoreline positions will continue to inform policy
decisions for shoreline management, and community resilience for the State. With this knowledge, as
the state adapts to higher sea levels, priority should be given to adaptation tools that protect, andenhance the public coastal resources and access. It is critical that developments, and redevelopments
be sited and designed to not require future protection that may alter a natural shoreline.

Conclusion
As sea level rise continues to accelerate, the State of Hawai`i must maintain a constant and ongoing
effort to adopt policies and programs to support adaptation to a changing world. Although there has
been progress made towards reducing vulnerability and enhancing adaptability, we must maintain adiligent focus on continual and ongoing improvement of community engagement, laws, regulations, andpolicies to meet the challenge ahead and safeguarding our cultural and natural resources while also
providing adaptation tools to the people of Hawai`i in an equitable manner. The recommendations
contained in the 2017 Report and this update provide key steps towards increasing the islands’
resiliency to sea level rise and many of the recommended actions provide co-benefits such as mitigating
impacts from storms and tsunami and improving overall community vitality. In the next five years, thestate must continue to work towards identifying and implementing programs which sustain vibrantcommunities while improving resilience to sea level rise and mitigating other natural hazards.

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Works Cited
Arias, P.A., et al. (2021) Technical Summary. In Climate Change 2021: The Physical Science Basis.
Contribution of WGI to the AR6 of the IPCC [Masson-Delmotte, V., et al. (eds.)]. Cambridge University
Press, Cambridge, UK and New York, NY, pp. 33−144. doi:10.1017/9781009157896.002.
Long, X., Widlansky, M. J., Schloesser, F., Thompson, P. R., Annamalai, H., Merrifield, M. A., & Yoon, H.
(2020). Higher sea levels at Hawaii caused by strong El Niño and weak trade winds. Journal of Climate,33(8), 3037-3059.
Nerem, R.S., Frederikse, T. and Hamlington, B.D., 2022. Extrapolating Empirical Models of Satellite‐
Observed Global Mean Sea Level to Estimate Future Sea Level Change. Earth's Future, 10(4),p.e2021EF002290.
Sweet, W.V., B.D. Hamlington, R.E. Kopp, C.P. Weaver, P.L. Barnard, D. Bekaert, W. Brooks, M. Craghan,
G. Dusek, T. Frederikse, G. Garner, A.S. Genz, J.P. Krasting, E. Larour, D. Marcy, J.J. Marra, J. Obeysekera,
M. Osler, M. Pendleton, D. Roman, L. Schmied, W. Veatch, K.D. White, and C. Zuzak, 2022: Global andRegional Sea Level Rise Scenarios for the United States: Updated Mean Projections and Extreme Water
Level Probabilities Along U.S. Coastlines. NOAA Technical Report NOS 01. National Oceanic andAtmospheric Administration, National Ocean Service, Silver Spring, MD, 111 pp.
https://oceanservice.noaa.gov/hazards/sealevelrise/noaa-nostechrpt01-global-regional-SLR-scenariosUS.pdf
Thompson, P.R., Widlansky, M.J., Hamlington, B.D., Merrifield, M.A., Marra, J.J., Mitchum, G.T. and
Sweet, W., 2021. Rapid increases and extreme months in projections of United States high-tide flooding.
Nature Climate Change, 11(7), pp.584-590.
Widlansky, M. J., Annamalai, H., Gingerich, S. B., Storlazzi, C. D., Marra, J. J., Hodges, K. I., ... & Kitoh, A.
(2019). Tropical cyclone projections: Changing climate threats for Pacific Island defense installations.
Weather, climate, and society, 11(1), 3-15.
IPCC (2021) Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis.
Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on
Climate Change [Masson- Delmotte, V., et al. (eds.)]. Cambridge Univ. Press. In Press.

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Appendix A
Responses to Learning Questions from the 2017 Hawai`i Sea Level
Rise Vulnerability and Adaptation Report
Sea Level Rise Outlook: Global and Local Observations and Projections
1. What are the observations of change in sea level in the vicinity of the Hawaiian Islands, and how dothey correspond with the recent global acceleration in mean sea level rise?
Long-term observational data from local tide gauge stations show that sea level is rising around Hawai‘i.
Models indicate that Hawai‘i and other tropical Pacific sites will experience sea level rise that is 16% to
20% higher than the global average (Sweet. et al. 2022). The NOAA 2022 report provides a range ofregionalized sea level rise scenarios based on differing GHG emissions pathways and associated global
warming and ice sheet melt. The report finds that sea level will rise around Hawaii between 0.7 and 1.5
feet by 2050. The Intermediate (mid-range) estimate is for a rise of 1.0 feet (relative to sea level in theyear 2000). The observed rate of sea level rise measured from tide gauges in Hawaii lead to a medianestimate of 0.8 feet by 2050, though this rate is expected to accelerate in coming decades similar to
global trends. Sea level will rise between 1.3 and 8.0 feet by 2100 (relative to the year 2000) with an
Intermediate estimate of 3.9 feet (Sweet, et al. 2022).
2. To what extent has the magnitude and timing of the sea level rise projections from IPCC AR5changed with new projections from the IPCC AR6?
Sea level rise exposure mapping in the 2017 Hawai‘i Sea Level Rise Report and Hawaii Sea Level Rise
Viewer is based on an upper-end projection in the 2013 IPCC 5th Assessment Report of 3.2 feet of global
mean sea level rise by 2100. As expected, the science on sea level rise observations and forecasts has
continued to advance. Since completion of the 2017 Report, peer-reviewed scientific literature as well as
government and multinational reports increasingly point to 3 to 4 feet of sea level rise by 2100 as a midrange, rather than high-end, scenario for Hawai‘i.
3. What are the observations and projections of the frequency and intensity of tropical cyclones and El
Niño events and their effects on coastal water levels and tidal flooding?
Major tropical cyclones (hurricanes) in Hawaii’s region of the Central North Pacific are much lesscommon than in the Eastern and Western tropical Pacific. From 1991-2020, an average of 3.6 tropicalstorms, 1.7 hurricanes (Category 1 or above), and 0.9 major hurricanes (Category 3 or above) occurred
per year in the Central Pacific (J. Marra and H. Diamond, NOAA, personal communication, November 2122, 2022). Of particular note in the past five years, Hurricane Walaka reached Category 5 status on
October 1, 2018 passing south and west of the main Hawaiian Islands but traveled directly overKānemilohaʻi (French Frigate Shoals) in Papahānaumokuākea Marine National Monument as a Category
3 hurricane (https://www.nhc.noaa.gov/data/tcr/CP012018_Walaka.pdf). East Island, a low-lying sandand gravel atoll island in French Frigate Shoals and an important green sea turtle nesting site, wasalmost completely washed away by Walaka’s waves and storm surge. Elevated sea surface temperaturesin the Central North Pacific (1.0º to 1.5º Celsius above average) and low wind shear contributed to
Walaka’s unusual strength (H. Diamond, NOAA, personal communication, November 21, 2022). While itA1

is difficult to blame climate change on a single storm event, Walaka may serve as an example ofincreasing tropical cyclone activity and impacts for Hawaii likely to occur in coming decades.
Advancing research since the 2017 SLR Report using climate models points to similar frequency but
increasing intensity of tropical cyclones around Hawaii, linked primarily to increased warming of ocean
surface waters (Widlansky, et al. 2019). El Nino conditions generally mean increased occurrence oftropical storms around Hawaii. The “triple dip” La Nina conditions over the past three years has likely
suppressed tropical cyclone activity around Hawaii over that time period due to cooler waters andincreased windshear (changes in wind speed and direction with altitude). Record high sea levels in 2017
have been linked to delayed effects from a strong El Nino in 2015 and climate model projections point toincreased periods of weak trade winds following El Nino events that have been linked to the occurrenceof high sea levels around Hawaii (Long, et al. 2020).

Methodology
1. To what extent do new global sea level rise projections differ from those used in this hazard
modeling?
Sea level rise exposure mapping in the 2017 Hawai‘i Sea Level Rise Report and Hawaii Sea Level Rise
Viewer is based on an upper-end projection in the 2013 IPCC 5th Assessment Report of 3.2 feet of global
mean sea level rise by 2100. As expected, the science on sea level rise observations and forecasts has
continued to advance. Since completion of the 2017 Report, peer-reviewed scientific literature as well as
government and multinational reports increasingly point to 3 to 4 feet of sea level rise by 2100 as a midrange, rather than high-end, scenario for Hawai‘i.
2. To what extent have data and coastal hazard modeling improved to warrant updating this hazard
modeling?
As current science, observations and projections evolve, the University of Hawai`i Climate Resilience
Collaborative is working to update and expand the State of Hawaii Sea Level Rise Viewer. Utilizing
federal funding, researchers are developing the next generation of passive flooding, high wave flooding,coastal erosion, compound events and other relevant sea level rise exposure map data that will beavailable in three to five years.
3. To what extent have property values, population, and other development trajectories changed
from the baseline data used in this report?
Property Values
The 2017 Report estimated that the value of private lands and structures within the SLR-XA on Oʻahu
was roughly $12.9 billion. A precise answer to this question was not attainable for the purposes of thisreport. Calculations of the change in property value are in progress by the University of Hawaiʻi Institutefor Sustainability and Resilience (ISR), led by Dr. Makena Coffman (personal communications, 2022).
Population
The 2017 Report states that “[o]ver the next 30 to 70 years, chronic flooding with sea level rise will
increase, impacting homes and businesses located near the shoreline. Approximately…19,800 people
statewide would be exposed to chronic flooding in the SLR-XA with 3.2 feet of sea level rise.” A precise
answer to this question was not attainable for the purposes of this report. Updated population
calculations are in progress by the ISR.
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Development
The 2017 Report states that “[o]ver the next 30 to 70 years, chronic flooding with sea level rise will
increase, impacting homes and businesses located near the shoreline. Approximately 6,500
structures…statewide would be exposed to chronic flooding in the SLR-XA with 3.2 feet of sea level rise.”Development trends throughout the state have not significantly changed since 2017, however the
recent and pending updates to county SMA and shoreline setback ordinances may affect coastal
development patterns moving forward.
4. Is the SLR-XA for 3.2 feet of sea level rise modeled in the Report still valid as the exposure overlay
for the mid to latter half of this century?
The latest science suggests that the SLR-XA for 3.2ft of sea level remains valid as a planning overlay forthe mid century at this time. Following the latest Sweet, et al., 2022 NOAA-interagency sea level rise
report, the State should update the guidance to set a planning and policy benchmark of 4 ft for allplanning and design for actions and infrastructure planned to 2100, and apply a 6 ft benchmark forplanning and design of public infrastructure projects and other projects with low tolerance for risk.

Results
1. To what extent is potential chronic flooding in the SLR-XA with 1.1 foot of sea level rise aligned withareas currently exposed to chronic flooding?
In 2017, and again in 2020, the Honolulu Harbor Tide gauge recorded the highest daily mean waterlevels observed over its 112-year history. These record high water levels were produced by a
combination of phenomena that included long-term global sea level rise, peak annual astronomical tides(“king tides”), wave setup, and migration of warm buoyant waters brought in by winds and currents.
During both events, observed sea levels tracked between 0.5 and 1 ft higher than predicted, providing a
glimpse of what will become a more common occurrence in the near future as sea level continues torise. Flooding observed during these events was widely documented as part of the Hawai`i and PacificIslands King Tides citizen science program. Local impacts were observed throughout the State in theform of increased coastal erosion, minor wave over-wash flooding, backshore flooding fromgroundwater rise and storm drain backflow, and impeded and potentially hazardous beach access.
Observations in low-lying areas like Mapunapua on Oahu confirmed flooding characterized by SLR-XA
passive flood layers representing the 1.1 ft scenario.
2. Are there any new developments or critical infrastructure in the SLR-XA with 3.2 feet of sea level
rise not accounted for in the vulnerability assessment?
State and County updated policies are designed to reduce the building of new homes and infrastructure
within the SLR-XA. In preparing this report, a full assessment of new development or criticalinfrastructure within the 3.2ft SLR-XA was not conducted. This report recommends a full vulnerability
assessment for the 2027 Report.
3. To what extent have land and structure values for parcels in areas potentially impacted by sea level
rise changed as a basis for estimating potential economic loss?
It is not clear that there has been any trend in shoreline development or retreat that would meaningfullychange the basis for estimating economic loss in the SLR-XA since the 2017 Report.
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4. To what extent has human migration from other Pacific Islands and wildlife migration from the
NWHI to the main Hawaiian Islands changed?
It is unknown at this time whether there has been a change in human and wildlife migration patterns
since the 2017 report.
5. What adaptation measures have been taken to reduce vulnerability to sea level rise?
Several adaptation measures have been taken throughout the state which reduce vulnerability to sea
level rise. Most of these are detailed in the Recommendations section of the report, and are highlighted
here briefly as specific measures which may reduce individual vulnerability to sea level rise.
The following is a general listing of actions which are further detailed in the Recommendations sectionin the body of this report:
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County of Kauaʻi passed first of its kind Sea Level Rise Constraint District that uses passive
flooding and wave runup models developed for Hawaiʻi Sea Level Rise Viewer. The constraint
district is a great example of resilient design standards for proposed uses within the SLR-XA.
The state implemented a disclosure requirement for real estate transactions for all properties
located within the sea level rise exposure area.
The state has sponsored or permitted beach nourishment activities in Waikiki and elsewhere
which improve resiliency by augmenting the beach profile and replacing eroded sand onto thebeach. Coupled with sand nourishment, some projects have also included groin construction inan effort to keep nourished sand on the beach.
In 2020, County of Kaua`i established a Special Treatment Coastal Edge District (ST-CE) as areasthat are highly vulnerable to coastal hazards including but not limited to sea level rise, coastal
erosion, high wave run-up, passive flooding, and an increased frequency and intensity of storms.
Within the ST-CE any use, structure, or development permitted with or without a Use Permit in
the Special Treatment Coastal Edge District shall mitigate impacts from coastal hazards,
including but not limited to sea level rise, coastal erosion, high wave run-up, passive flooding,and an increased frequency and intensity of storms.
Along the elevated portions of the Honolulu Rail Transit Project between Chinatown and Ala
Moana Center the stations were redesigned so no electronics below 6ft and elevated portions
meet federal requirements even if roads are raised by 6ft. Additionally, all hanging elements
were removed to allow for 6ft of adaptation.
Sidewalks and entryways in Kaka`ako are elevated above street level to account for flooding.
The City and County of Honolulu and the Maui County both issued Mayoral Declarations
requiring executive departments to consider and incorporate SLR-XA data for capital planning.
City and County of Honolulu Department of Planning and Permitting instituted a requirement
for consideration of sea level rise for all building permits and for all properties conducting
renovations within the SLR-XA.

Recommendations
1. What recommendations have been implemented and why?
The status of the recommendations and recommended actions contained in the 2017 Report is covered
in detail in the body of this report. Progress towards meeting the nine recommendations (represented
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by large circles) and 49 associated recommended actions (represented by small circles) is presented
here as measured on a qualitative scale of “no known progress” to “significant progress”.

Some key statewide accomplishments that address the recommendations are noted as follows:
Use of the Sea Level Rise Exposure Area Data and Sea Level Rise Viewer: Although the Sea Level Rise
Exposure Area (SLR-XA) was not officially recognized as a state-wide vulnerability zone, the Viewer and
SLR-XA are in widespread use by state and county agencies for adaptation planning purposes. The useof the SLR-XA data as identified by the Viewer for policy decisions was enabled by the peer reviewed
publication of the methods, which allowed for the removal of the original disclaimer language
cautioning against such use. Easy availability and the establishment of guidance for SLR-XA datainterpretation via the viewer made it critically important to the success of planning efforts and new
policies. We recommend a continual peer review of ongoing research to strengthen the research
products used in policy decision making.
Hawai`i Coastal Zone Management Act Updates: Act 16, SLH2020 updated the Hawai`i Coastal Zone
Management Act (HRS Chapter 205A) in many ways including strengthening protections for beach andA5other coastal environments by specifically prohibiting private shoreline hardening structures andminimizing public shoreline hardening structures, including seawalls and revetments, at sandy beaches
where they would interfere with existing recreational and waterline activities.
Sea Level Rise Report Addendum: Guidance for Using the Sea Level Rise Exposure Area in Local
Planning and Permitting Decisions was published by the State as a supplement to the 2017 Report. The
Addendum was prepared by the University of Hawai`i Sea Grant College Program with the Hawai`i
Department of Land and Natural Resources - Office of Conservation and Coastal Lands for the Hawai`i
Climate Change Mitigation and Adaptation Commission - Climate Ready Hawai`i Initiative. The Hawai`i
Climate Change Mitigation and Adaptation Commission issued a statement of approval for the
Addendum at its October 28 2020 meeting.
Hawai`i 2018 Hazard Mitigation Plan: The 2018 update of the State’s Hazard Mitigation Plan includes
expanded consideration of climate change and sea level rise hazards, including hazard assessment using
the SLR-XA and a 1% Annual-Chance Coastal Flood Zone with 3.2 feet of sea level rise (1%CFZ-3.2)
modeled for the Plan: https://dod.hawaii.gov/hiema/sert-resources/hazard-mitigation/
Planning for Managed Retreat: OPSD-CZM published a report titled Assessing the Feasibility andImplications of Managed Retreat Strategies for Vulnerable Coastal Areas in Hawai`i in 2019 and isembarking on a next-step study that will assess the options for and implications of implementing
managed retreat from the perspectives of (1) policy and regulation, and (2) funding and financing
mechanisms in 2023.
Statewide Inventory of Vulnerable Infrastructure: Act 178 Relating to Sea Level Rise Adaptation was
passed to begin the long-term planning needed to effectively address climate impacts. OPSD-CZM
submitted a report to the legislature in 2021 reporting on progress towards the phased approachrequired by Act 178.
In addition to the above listed state-wide highlights, the ongoing support from University of Hawai`ientities such as the Sea Grant College Program, the Climate Resilience Collaborative, and others) to stateand county agencies provided expertise for interpretation of the report and practical implementation ofrecommendations and use of data. The capacity to address the impacts of sea-level rise grew at county
and state levels of government. For example, the City and County of Honolulu established the City andCounty of Honolulu established the Climate Change Commission. The City and County of Honolulu andthe County of Maui established an Office of Climate Change, Sustainability and Resiliency; the County of
Hawaii maintains a Climate Change Action program within its Office of Research and Development andthe County of Kauai maintains a Sustainability Program Area within its Office of Economic Development.
2. What recommendations have not been implemented and why?
Although the state made progress towards implementing the recommendation of the 2017 Report,
there are areas of unmet need that require a renewed focus over the next five years.
●●

Facilitate interagency coordination for holistic adaptation planning (e.g., comprehensive
consideration and planning for natural resources, roads, communities; and improved
communications between government agencies) (2017 Recommendation 9, 2022
Recommendation 1)
Conserve and adapt Native Hawaiian cultural resources and sites (2017 Recommendation 5)
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●
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Integrate equity and justice considerations to vulnerability assessments and adaptation
planning and actions (2017 Recommendation 2)
Address and stop the loss of shoreline access (2017 Recommendation 4)
Integrate economic valuation and ecosystem co benefits of natural coastal resources intoplanning and actions (2017 Recommendations 4, 5 and 8)
Make managed retreat a viable option and identify funding mechanisms for adaptation (2017
Recommendations 2 and 7)
Implement phased adaptation to sea level rise (2017 Recommendation 1, 2, 7)

The status of the recommendations and recommended actions contained in the 2017 Report is covered
in detail in the body of this report.
The summary graphic in the answer to question 2 in this section captures recommendations andrecommended actions for which no action and/or little progress was reported.
The 2017 Recommendations were adopted by the State Climate Commission but were not specificallyassigned to individual agencies for action. As a result, individual agencies prioritize and implement new
programs or policies aligned with their strategic goals, and not in response to all recommendations fromthe 2017 Report. Overall funding and personnel capacity also hinder progress towards implementing
the recommendations and recommended actions.
3. What have been barriers to implementation and measures taken to overcome these barriers?
The COVID pandemic caused delays to action across the federal, state and county government agencies.
Although capacity to address climate change and sea level rise increased at the state and county levels,
there is a need for additional personnel and funding as outlined in the updated recommendations in thisreport. Additionally, specific to the implementation of progressive shoreline setback ordinances, there
is a need for public engagement and education regarding the need and benefit for increased setback
distances. Opposition from property rights advocates will continue to be an issue when attempting to
implement stricter setback rules.
There is also a lack of funding mechanisms to enable managed retreat. The ongoing work of OPSD-CZM
to study the various possibilities should be supported and the findings of the initial study should be
implemented.

4. To what extent has Hawaii’s capacity to adapt to sea level rise increased based on benchmarks andmeasurable indicators?
Among the updated recommendations presented in this interim report is a focus on the facilitation ofinteragency coordination for holistic adaptation planning and greater resources dedicated to tracking
and integrating agency initiatives and efforts towards adaptation. There are currently no benchmarks or
measurable indicators to measure the State’s progress towards sea level rise adaptation. In order toobjectively assess Hawaii’s capacity to adapt to sea level rise, we must set benchmarks for measurement
and all state and county agencies must adopt and utilize those benchmarks.

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This Report did not undertake an effort to assess reductions in vulnerability or increased capacity toadapt to sea level rise based on the implementation of the recommended actions. We recommend thatthe state should conduct a full review of all actions taken in response to the 2017 and 2022
recommendations to determine the reduction in vulnerability for areas within the exposure area. as partof the 10-Year Update.

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