Establishing a Sea Level Rise-Adjusted Design Flood Elevation for Buildings: A Comparative Study of Methods
Abstract
1. Introduction
1.1. Existing Flood Hazards and Building Requirements
1.2. Sea Level Rise Scenarios and Impacts
1.3. The Need to Compare Methods to Establish Sea Level Rise-Adjusted DFEs
2. Materials and Methods
2.1. Factors and Criteria for a Sea Level Rise-Adjusted Design Flood Elevation
2.1.1. Author/Entity
2.1.2. Starting Point for Measuring SLR-DFEs
2.1.3. SLR Scenario and Timeframe
2.1.4. SLR Adjustment
2.1.5. Freeboard
2.1.6. Design Flood Elevations
2.1.7. Application
2.1.8. Requirement or Recommendation
2.2. Selection Criteria for Comparing Sea Level Rise-Adjusted Design Flood Elevations (SLR-DFE)
- sea level rise [and] elevation [and] flood-* [and] adapt-* [and] design (35 results);
- sea level rise design flood elevation (55 results);
- design elevation sea level rise (168 results);
- adaptation design flood levels sea level rise (179 results);
- allowance flood damage sea level rise (4 results);
- uncertainty sea level rise design buildings (30 results);
- uncertain-* [and] adapt-* [and] design [and] sea level rise [and] build-* (26 results);
- uncertain-* [and] adapt-* [and] design [and] sea level rise [and] built (8 results);
- sea level rise building adaptations [and] elevat-* [and] flood (32 results);
- building adaptations [and] sea level rise finished-floor (2 results); and
- sea level rise finished-floor level (3 results).
- ASCE (national-existing);
- New York City, NY (municipal);
- Boston, MA (municipal);
- Kauaʻi, HI (county and district);
- Florida (municipal, regional and state);
- Rhode Island (state); and
- Federal Flood Risk Management Standard (national-future).
2.3. Developing a Visual Comparison of SLR-DFEs
3. Relevant Initiatives
3.1. Summary of Approaches by Initiative (Locations/Guidance Studied)
3.1.1. FEMA and ASCE Guidance on Building Elevation (National)
3.1.2. New York City (Municipal)
Factor/Criteria | Approach |
---|---|
Author/Entity | NYC Mayor’s Office of Climate and Environmental Justice |
Starting Elevation Measurement | Measured from FEMA BFE.(BFE Measured from NAVD 88; FEMA 1% Preliminary FIRM (PFIRM) (2015) or FIRM (2007).) |
SLR Scenario and Timeframe | Middle of the 25th–75th percentile range projections from the NPCC. 2 |
SLR Adjustment | Based on end of useful building life (range):
|
Freeboard | 24″ (0.61 m) |
Design Flood Elevations | SLR-DFE = BFE + SLR adjustment + Freeboard |
Application | Applies to all city capital projects (new construction and substantial improvements) except coastal flood protection systems. Applies to city critical and non-critical buildings (defined by NYC) within current or future 1% annual chance flood plain. |
Requirement or Recommendation | Required for NYC capital projects (starting 2026) |
3.1.3. City of Boston (Municipal)
3.1.4. Kauaʻi, Hawaiʻi (County and District)
3.1.5. Florida (State, Regional and Municipal)
3.1.6. Rhode Island (State)
Factor/Criteria | Approach |
---|---|
Author/Entity | RI CRMC, Shoreline Change Special Area Management Plan, and STORMTOOLS. |
Starting Elevation Measurement | Once in 100-year (1% chance) return period storm scenario referenced to NAVD 88. |
SLR Scenario and Timeframe | Choose an appropriate design life and identify the associated projected sea level. The Coastal Hazard Application recommends a minimum 30 year “design life” be considered. CRMC policy, RICRMP Section 145, relies on the “high” sea level change curve [84] included in the most recent NOAA sea level rise data [2].
|
SLR Adjustment | Maps illustrating SLR depths of 2′ (0.61 m), 3′ (0.91 m), 5′ (1.52 m), 7′ (2.13 m), 10′ (3.05 m) (are available in STORMTOOLS. 2 Maps illustrating a 100-year return period (1% annual chance) COASTAL STORM with or without 2 feet (0.61 m) of SLR are available in STORMTOOLS. SLR scenarios are relative to 2010 and suggested design elevations are referenced to NAVD 88. |
Freeboard | Recommended: 1 foot (0.30 m) of freeboard (elevation) above BFE is required but up to 5 feet (1.52 m) of additional freeboard may be provided voluntarily. It is unclear if freeboard should be added to the SDE (described below). Standards for Shallow Flooding Zones (A-Zones) in SFHZs:
Critical facilities: 2′–0″ (0.61 m) (minimum) lowest floor either elevated or dry floodproofed to or above the 500-year flood plus 2 feet (0.61 m) of freeboard |
Design Flood Elevations | SLR-DFE = 100-year return period storm scenario + SLR based on design life + Freeboard STORMTOOLS uses the term STORMTOOLS Design Elevation (SDE) to represent the “once in hundred year flooding and associated wave environment”, and SLR of varying depths (and does not mention freeboard). |
Application | All projects (new or expanding residential, commercial, industrial) within the CRMC jurisdiction require a CRMC permit. |
Requirement or Recommendation | Freeboard for substantial improvements for critical facilities is required. Permit is required by the Coastal Resources Management Council (CRMC)’s jurisdiction (extending from the territorial sea limit to two hundred feet (60.96 m) inland from any coastal feature). Permit requires completion of Coastal Hazard Application Worksheet and Viewer and design evaluation. SAMP includes additional adaptation recommendations from FM Global, an insurance company. |
3.1.7. Federal Flood Risk Management Standard (National)
3.2. Visual Comparison of SLR-Adjusted DFE
4. Discussion
4.1. Observations and Challenges in the Development of SLR-Adjusted DFEs
4.1.1. Author/Entity
4.1.2. Starting Point for Measuring SLR-DFEs
4.1.3. SLR Scenario and Timeframe
4.1.4. SLR Adjustment
4.1.5. Freeboard
4.1.6. SLR-Adjusted Design Flood Elevations
4.1.7. Application
4.1.8. Requirement or Recommendation
4.2. Potential Application, Next Steps, and Future Research Needs
- As the initiatives studied are implemented, future research on new and renovated buildings is needed to evaluate the SLR-DFE’s ease of application, adherence rate, first cost, effectiveness during a flood, potential cost savings, etc.
- Quantify an SLR-DFE that includes SLR in combination with wave velocity in the FEMA FIRM Zone V or VE areas.
- Understand if or when an SLR-DFE should consider the water level described by the 1% annual exceedance probability level, which combines astronomical tide, storm surge, and limited wave setup, but excludes wave runup [94]. This is different from the FEMA FIRMs BFE 1% annual chance flood.
5. Conclusions
Establishing Local Building Elevation Levels for an SLR Affected Future
Supplementary Materials
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
Abbreviations
SLR | sea level rise |
BFE | base flood elevation |
DFE | design flood elevation |
SLR-BFE | sea level rise-adjusted base flood elevation |
SLR-DFE | sea level rise-adjusted design flood elevation |
FEMA | Federal Emergency Management Agency |
References
- NOAA Office for Coastal Management. Fast Facts: High Tide Flooding. n.d. Available online: https://coast.noaa.gov/states/fast-facts/recurrent-tidal-flooding.html (accessed on 1 February 2025).
- Sweet, W.V.; Hamlington, B.D.; Kopp, R.E.; Weaver, C.P.; Barnard, P.L.; Bekaert, D.; Brooks, W.; Craghan, M.; Dusek, G.; Frederikse, T.; et al. Global and Regional 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 and Atmospheric Administration, National Ocean Service: Silver Spring, MD, USA, 2022. Available online: https://earth.gov/sealevel/us/internal_resources/756/noaa-nos-techrpt01-global-regional-SLR-scenarios-US.pdf (accessed on 1 July 2025).
- Ohenhen, L.O.; Shirzaei, M.; Ojha, C.; Sherpa, F.S.; Nicholls, R.J. Disappearing Cities on US Coasts. Nature 2024, 627, 108–115. [Google Scholar] [CrossRef] [PubMed]
- American Institute of Architects. Hazard and Climate Risk: A User’s Guide and Form for Acknowledging Risk. Available online: https://www.aia.org/sites/default/files/2024-11/Hazard_and_Climate_Risk_Acknowledgement_Form.pdf (accessed on 1 February 2025).
- Ianchenko, A.; Kathrina, S.; Clayton, B. Residential Building Lifespan and Community Turnover. J. Archit. Eng. 2020, 26, 04020026. [Google Scholar] [CrossRef]
- USGS. How Can Climate Change Affect Natural Disasters? Available online: https://www.usgs.gov/faqs/how-can-climate-change-affect-natural-disasters (accessed on 1 February 2025).
- Spaulding, M.L.; Grilli, A.; Damon, C.; Hashemi, R.; Kouhi, S.; Fugate, G. Stormtools Design Elevation (SDE) Maps: Including Impact of Sea Level Rise. J. Mar. Sci. Eng. 2020, 8, 292. [Google Scholar] [CrossRef]
- Peri, C.; Stephanie, R.; Jessica, Y. Population in the U.S. Floodplains. Data Brief. NYU Furman Center. 2017. Available online: https://furmancenter.org/files/Floodplain_PopulationBrief_12DEC2017.pdf (accessed on 1 February 2025).
- FEMA. Residential Buildings with Basements|FEMA.Gov. 2023. Available online: https://www.fema.gov/floodplain-management/manage-risk/residential-buildings-basements (accessed on 1 February 2025).
- FEMA. FEMA Glossary|BFE. 2024. Available online: https://www.fema.gov/about/glossary (accessed on 1 February 2025).
- FEMA. Flood Insurance Study (FIS). 8 July 2020. Available online: https://www.fema.gov/glossary/flood-insurance-study-fis (accessed on 1 February 2025).
- FEMA. How to Read a Flood Map. RiskMAP. 2022. Available online: https://www.fema.gov/sites/default/files/documents/how-to-read-flood-insurance-rate-map-tutorial.pdf (accessed on 1 February 2025).
- FEMA. Flood Data Viewers and Geospatial Data. n.d. Available online: https://www.fema.gov/flood-maps/national-flood-hazard-layer (accessed on 1 February 2025).
- FEMA. Freeboard. 8 July 2020. Available online: https://www.fema.gov/glossary/freeboard (accessed on 1 February 2025).
- FEMA. Designing for Flood Levels Above the Minimum Required Elevation After Hurricane Ian. DR-4673-FL RA 1. Federal Emergency Management Agency, 2023. Available online: https://www.fema.gov/sites/default/files/documents/fema_mat-hurricane-ian-recovery-advisory-1.pdf (accessed on 1 February 2025).
- NASA. Interagency Sea Level Rise Scenario Tool. In NASA Sea Level Change Portal. 2022. Available online: https://sealevel.nasa.gov/task-force-scenario-tool (accessed on 1 February 2025).
- City and County of Honolulu (CCH) Climate Change Commission. Sea Level Rise II-Guidance Document. 2022. Available online: https://www.resilientoahu.org/s/HonoluluClimateChangeCommission-SeaLevelRiseGuidance_Updated-July2022-sadb.pdf (accessed on 1 February 2025).
- Habel, S.; Fletcher, C.H.; Anderson, T.R.; Thompson, P.R. Sea-Level Rise Induced Multi-Mechanism Flooding and Contribution to Urban Infrastructure Failure. Sci. Rep. 2020, 10, 3796. [Google Scholar] [CrossRef] [PubMed]
- Crimmins, A.; Avery, C.; Easterling, D.; Kunkel, K.; Stewart, B.; Maycock, T. Fifth National Climate Assessment; U.S. Global Change Research Program, 2023. [Google Scholar] [CrossRef]
- CCH Climate Change Commission. Climate Change Brief. 2023. Available online: https://static1.squarespace.com/static/5e3885654a153a6ef84e6c9c/t/64374370c0631e3ac922692a/1681343347345/Climate+Change+Brief+2023.pdf (accessed on 1 July 2025).
- AIA. The Climate Imperative. 2020. Available online: https://content.aia.org/sites/default/files/2020-07/AIA_Climate_Action_Plan.pdf (accessed on 1 February 2025).
- Rasmussen, D.J.; Buchanan, M.K.; Kopp, R.E.; Oppenheimer, M. A Flood Damage Allowance Framework for Coastal Protection with Deep Uncertainty in Sea Level Rise. Earth’s Future 2020, 8, e2019EF001340. [Google Scholar] [CrossRef] [PubMed]
- NIBS. Mitigation Saves up to $13 per $1 Invested; National Institute of Building Sciences. 2020. Available online: https://nibs.org/wp-content/uploads/2025/04/ms_v4_overview.pdf (accessed on 1 July 2025).
- Botzen, W.J.W.; Aerts, J.C.J.H.; van den Bergh, J.C.J.M. Individual Preferences for Reducing Flood Risk to near Zero through Elevation. Mitig. Adapt. Strateg. Glob. Change 2013, 18, 229–244. [Google Scholar] [CrossRef]
- Joshua, K.; Mark, S.; Elizabeth, K.C.; Iris, M.; Tom, S.; Athanasios, T.V. Effective Design of Managed Realignment Schemes Can Reduce Coastal Flood Risks. Estuar. Coast. Shelf Sci. 2020, 242, 106844. [Google Scholar] [CrossRef]
- Pearson, C. An Advocate’s Guide to Resilience Regulations; BuildingGreen, Inc. 2021. Available online: https://www.buildinggreen.com/spotlight/advocate#:~:text=This%20report%20takes%20a%20look,toward%20greater%20levels%20of%20resilience (accessed on 1 July 2025).
- NYC Mayor’s Office of Climate and Environmental Justice. Climate Resiliency Design Guidelines; NYC Mayor’s Office of Climate & Environmental Justice, 2022. Available online: https://www1.nyc.gov/assets/sustainability/downloads/pdf/publications/CRDG-4-1-May-2022.pdf (accessed on 1 July 2025).
- National Climate Task Force. Federal Flood Risk Management Standard Climate-Informed Science Approach (CISA) State of the Science Report; National Climate Task Force. 2023. Available online: https://www.epa.gov/system/files/documents/2024-08/ffrms-climate-informed-science-approach-state-of-the-science-report.pdf (accessed on 1 February 2025).
- NOAA. NOAA Tides & Currents: Relative Sea Level Trends. 2024. Available online: https://tidesandcurrents.noaa.gov/sltrends/ (accessed on 1 January 2024).
- FEMA. n.d. Appendix B: How to Read a Flood Insurance Rate Map (FIRM) Course Glossary. Available online: https://emilms.fema.gov/is_0273/groups/157.html (accessed on 1 April 2025).
- USGS. n.d. What Is the Difference between a Sinkhole and Land Subsidence? USGS Science for a Changing World. Available online: https://www.usgs.gov/faqs/what-difference-between-a-sinkhole-and-land-subsidence (accessed on 7 March 2024).
- Low, D.K.; Deborah, M.; Rebecca, Q.; Adam, R.; John, S. Protecting Building Utility Systems from Flood Damage: Principles and Practices for the Design and Construction of Flood Resistant Building Utility Systems. FEMA P-348, 2nd ed.; Federal Emergency Management Agency, 2017. Available online: https://www.fema.gov/sites/default/files/2020-07/fema_p-348_protecting_building_utility_systems_from_flood_damage_2017.pdf (accessed on 1 July 2025).
- FEMA. Principles and Practices for the Design and Construction of Flood Resistant Building Utility Systems: Appendix B-Glossary of Terms. November 1999. Available online: https://www.fema.gov/pdf/fima/pbuffd_appendix_b.pdf (accessed on 1 February 2025).
- Coulbourne, W.; Christopher, P.J.; Omar, K.; Vasso, K.; Philip, L.; David, K.L.; Glenn, O.; Passman, S.; Reeder, A.; Seitz, A.L.; et al. Coastal Construction Manual: Principles and Practices of Planning, Siting, Designing, Constructing, and Maintaining Residential Buildings in Coastal Areas; U.S. Department of Homeland Security, 2011. Available online: https://www.fema.gov/sites/default/files/2020-08/fema55_voli_combined.pdf (accessed on 1 February 2025).
- FEMA. Highlights of ASCE 24-14: Flood Resistant Design and Construction; U.S. Department of Homeland Security, 2015. Available online: https://www.fema.gov/sites/default/files/2020-07/asce24-14_highlights_jan2015.pdf (accessed on 1 February 2025).
- American Society of Civil Engineers (ASCE). ASCE 24 Flood Resistant Design and Construction. ASCE/SEI 24-14; American Society of Civil Engineers: Reston, VA, USA, 2015; Available online: https://ndl.ethernet.edu.et/bitstream/123456789/58215/1/638.pdf (accessed on 1 February 2025).
- ASCE. ASCE 24 Flood Resistant Design and Construction. ASCE/SEI 24-24; American Society of Civil Engineers: Reston, VA, USA, 2025; Available online: https://ascelibrary.org/doi/book/10.1061/9780784485781 (accessed on 1 April 2025).
- Association of State Floodplain Managers (ASFPM). ASCE 24-24 Delivers Major Update to Flood Resistant Design Standards. 2025. Available online: https://www.floods.org/news-views/flood-mitigation/asce-24-24-delivers-major-update-to-flood-resistant-design-standards/ (accessed on 1 April 2025).
- NYC Mayor’s Office of Climate and Environmental Justice. New York City Panel on Climate Change (NPCC). 2025. Available online: https://climate.cityofnewyork.us/initiatives/nyc-panel-on-climate-change-npcc/ (accessed on 1 May 2025).
- New York City Council. Local Law 2021/41. 2021. Available online: https://legistar.council.nyc.gov/LegislationDetail.aspx?ID=4648590&GUID=F7CCBD21-44D7-4280-AB54-3D419D2AE033&Options=&Search= (accessed on 1 May 2025).
- NYC Mayor’s Office of Climate and Environmental Justice. Climate Resiliency Design Guidelines. n.d. Available online: https://climate.cityofnewyork.us/initiatives/climate-resiliency-design-guidelines/ (accessed on 1 May 2025).
- NYC Department of City Planning. NYC Flood Hazard Mapper. 2017. Available online: https://dcp.maps.arcgis.com/apps/webappviewer/index.html?id=1c37d271fba14163bbb520517153d6d5 (accessed on 1 May 2025).
- Horton, R.; Little, C.; Gornitz, V.; Bader, D.; Oppenheimer, M. New York City Panel on Climate Change 2015 Report Chapter 2: Sea Level Rise and Coastal Storms. Ann. N. Y. Acad. Sci. 2015, 1336, 36–44. [Google Scholar] [CrossRef] [PubMed]
- Boston Planning & Development Agency (BPDA). Coastal Flood Resilience Design Guidelines; Boston Planning & Development Agency: Boston, MA, USA, 2019; Available online: https://www.bostonplans.org/getattachment/d1114318-1b95-487c-bc36-682f8594e8b2 (accessed on 1 February 2025).
- Bosma, K.; Ellen, D.; Paul, K.; Katherin, M.; Steven, M.; Chris, W. MassDOT-FHWA Pilot Project Report: Climate Change and Extreme Weather Vulnerability Assessments and Adaptation Options for the Central Artery; MassDOT-FHWA: Boston, MA, USA, 2015; Available online: https://www.cakex.org/sites/default/files/documents/MassDOT_FHWA_Climate_Change_Vulnerability_1.pdf (accessed on 1 February 2025).
- Parris, A.S.; Bromirski, P.; Burkett, V.; Cayan, D.R.; Culver, M.E.; Hall, J.; Horton, R.M.; Knuuti, K.; Moss, R.H.; Obeysekera, J.; et al. Global sea level rise scenarios for the United States National Climate Assessment. 2012. Available online: https://repository.library.noaa.gov/view/noaa/11124 (accessed on 1 April 2025).
- BPDA. Flood Resiliency Building Guidelines & Zoning Overlay District. Government Planning; Bostonplans.Org. 2023. Available online: https://www.bostonplans.org/planning/planning-initiatives/flood-resiliency-building-guidelines-zoning-over (accessed on 1 February 2025).
- Boston Planning & Development Agency (BPDA). Boston Zoning Code Article 25A Coastal Flood Resilience Review Procedures and Submittal Requirements; Boston Planning & Development Agency. 2021. Available online: https://www.bostonplans.org/getattachment/206a310f-5215-43df-8cef-3dd9a4974215 (accessed on 1 February 2025).
- County of Kaua’i 2022. § 8-12.5: Sea Level Rise District (S-SLR). 14 October 2022. Available online: https://ecode360.com/42671502 (accessed on 1 April 2025).
- County of Kaua’i. West Kaua’i Community Plan. Kaua’i, Hawai’i. 2020. Available online: https://www.kauai.gov/files/assets/public/v/1/planning-department/documents/west-kauai-community-plan_final.pdf (accessed on 1 February 2025).
- County of Kaua’i Planning Department. A Bill for an Ordinance Amending Chapter 8, Kaua’i County Code 1987, As Amended, by Establishing a New Special Treatment Coastal Edge (ST-CE) District and Amending Zoning Maps ZM-KL00 (Kekaha), ZM-WL00 (Waimea), ZM-200, and ZM-H200 (Hanapepe). Available online: https://kauai.granicus.com/MetaViewer.php?meta_id=144738 (accessed on 1 February 2025).
- Hawai’i Climate Change Mitigation and Adaptation Commission. Hawai’i Sea Level Rise Vulnerability and Adaptation Report; Tetra Tech, Inc.: Pasadena, CA, USA; State of Hawai’i Department of Land and Natural Resources, Office of Conservation and Coastal Lands: Honolulu, HI, USA, 2017. [Google Scholar]
- Florida Department of Environmental Protection. Resilient Florida Program. n.d. Available online: https://floridadep.gov/rcp/resilient-florida-program (accessed on 1 July 2025).
- Florida Department of Environmental Protection. Florida Statewide Vulnerability Assessment. Comprehensive Statewide Flood Vulnerability and Sea Level Rise Assessment (Modeling and Predicting Vulnerable Areas). n.d. Available online: https://floridadep.gov/rcp/resilient-florida-program/content/resilient-florida-program-statewide-assessment (accessed on 1 April 2025).
- Florida Department of Environmental Protection. Resilient Florida Program-SLIP. n.d. Available online: https://floridadep.gov/rcp/resilient-florida-program/content/resilient-florida-program-slip (accessed on 2 February 2024).
- Florida Department of Environmental Protection. Statewide Vulnerability Assessment. (Map Viewer) Sea Level Impact Projection (SLIP) Study Report. n.d. Available online: https://prodapps.dep.state.fl.us/orcp-sva/ (accessed on 1 April 2025).
- Florida Department of Environmental Protection. Florida Administrative Code, Rule 62S-7.012: SLIP Study Standards; Florida Administrative Register, 50(249). ID: 28447595; Florida Department of Environmental Protection: Tallahassee, FL, USA, 2024; Available online: https://flrules.org/Gateway/View_notice.asp?id=28447595 (accessed on 1 July 2025)Florida Administrative Register, 50(249). ID: 28447595.
- Florida Legislature; Florida Statutes. Resilient Florida Grant Program; Comprehensive Statewide Flood Vulnerability and Sea Level Rise Data Set and Assessment; Statewide Flooding and Sea Level Rise Resilience Plan; Regional Resilience Entities; Title XXVIII, Chapter 380, Section 380.093; Florida Legislature. Florida Statutes: Tallahassee, FL, USA, 2024; Available online: http://www.leg.state.fl.us/Statutes/index.cfm/Ch0316/index.cfm?App_mode=Display_Statute&URL=0300-0399/0380/0380.html (accessed on 9 April 2025).
- Florida Department of Environmental Protection. Florida Administrative Code, Rule 62S-7.012: SLIP Study Standards; Florida Administrative Register, 50(249). ID: 24642188; Florida Department of Environmental Protection: Tallahassee, FL, USA, 2021; Available online: https://flrules.org/Gateway/View_notice.asp?id=24642188 (accessed on 1 July 2025).
- State of Florida. Committee Substitute for Senate Bill No. 1094: Peril of Flood. Chapter 2015-69; 2015; Tallahassee: State of Florida. Available online: https://www.flsenate.gov/Session/Bill/2015/1094/BillText/c1/PDF (accessed on 1 July 2025).
- Florida Coastal Management Program (FCMP); Florida Department of Environmental Protection; NOAA. Florida Adaptation Planning Guidebook. 2018. Available online: https://floridadep.gov/sites/default/files/AdaptationPlanningGuidebook.pdf (accessed on 1 February 2025).
- Southeast Florida Regional Climate Change Compact (Compact). What Is the Compact? n.d. Available online: https://southeastfloridaclimatecompact.org/what-is-the-compact/ (accessed on 1 April 2025).
- Southeast Florida Regional Climate Change Compact Sea Level Rise Work Group (Compact). Unified Sea Level Rise Projection: Southeast Florida; February 2020. Available online: https://southeastfloridaclimatecompact.org/wp-content/uploads/2023/10/2019-sea-level-projections.pdf (accessed on 1 February 2025).
- IPCC. Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects. In Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change; Field, C.B., Barros, V.R., Dokken, D.J., Mach, K.J., Mastrandrea, M.D., Bilir, T.E., Chatterjee, M., Ebi, K.L., Estrada, Y.O., Genova, R.C., Eds.; Cambridge University Press: Cambridge, UK; New York, NY, USA, 2014; p. 1132. [Google Scholar]
- Sweet, W.V.; Kopp, R.E.; Weaver, C.P.; Obeysekera, J.; Horton, R.M.; Thieler, E.R.; Zervas, C. Global and Regional Sea Level Rise Scenarios for the United States; NOAA Technical Report NOS CO-OPS 083; NOAA; 2017. Available online: https://tidesandcurrents.noaa.gov/publications/techrpt83_Global_and_Regional_SLR_Scenarios_for_the_US_final.pdf (accessed on 1 February 2025).
- City of Miami Beach. Land Development Regulations (Resiliency Code). 6 June 2023. Available online: https://codehub.gridics.com/us/fl/miami-beach (accessed on 1 May 2025).
- Miami Beach Rising Above. Resilience Code. 2025. Available online: https://www.mbrisingabove.com/your-city-at-work/resilience-strategy/resilience-code/ (accessed on 1 April 2025).
- City of Miami Beach. Freeboard. Ordinance No. 2016-4009. 2016. Available online: https://www.mbrisingabove.com/wp-content/uploads/2017/11/2016-4009-Ordinance.pdf (accessed on 1 February 2025).
- City of Miami Beach; AECOM. City of Miami Beach: Sea Level Rise Vulnerability Assessment Report. September 2024. Available online: https://www.mbrisingabove.com/wp-content/uploads/Final-VA-Report_Compress.pdf (accessed on 1 February 2025).
- City of Miami Beach; AECOM. Sea Level Rise Adaptation Plan (Draft). 2025. Available online: https://www.mbrisingabove.com/wp-content/uploads/CMB_SLR_Adaptation_03032025.pdf (accessed on 1 July 2025).
- City of Miami Beach. Code of Ordinances: Chapter 54-Floods. Municode Library, 2025; Available online: https://library.municode.com/fl/miami_beach/codes/code_of_ordinances?nodeId=SPAGEOR_CH54FL (accessed on 1 April 2025).
- Florida Department of Environmental Protection. Coastal Construction Control Line Program. n.d. Available online: https://floridadep.gov/rcp/coastal-construction-control-line (accessed on 1 April 2025).
- Satellite Beach. Code of Ordinances. § 30-738. Design Standards; Municode Library; Available online: https://library.municode.com/fl/satellite_beach/codes/code_of_ordinances?nodeId=PTIICICO_CH30LADERE_ARTVIIREPR_DIV4COCOCOLICCSTCR_S30-738DEST (accessed on 18 March 2025).
- Satellite Beach. Code of Ordinances. § 30-739. Variances and Action by the Board of Adjustment; Municode Library; Available online: https://library.municode.com/fl/satellite_beach/codes/code_of_ordinances?nodeId=PTIICICO_CH30LADERE_ARTVIIREPR_DIV4COCOCOLICCSTCR_S30-739VAACBOAD (accessed on 1 April 2025).
- Ruppert, T.; Erin, D. City of Satellite Beach: Policy Recommendations for Resiliency. (Attachment 2) Agenda City Council Regular Meeting. 2019. Available online: https://library.municode.com/fl/satellite_beach/munidocs/munidocs?nodeId=32a07ee67232d (accessed on 1 July 2025).
- City of Satellite Beach. 2022 Sustainability Action Plan. 18 January 2023. Available online: https://satellitebeach.gov/residents/sustainable_satellite/sustainability_action_plan/sustainability_action_plan.php (accessed on 1 April 2025).
- Evans, J.M.; Mitchell, E.; Carr, A.; Goodison, C.; Zwick, P.; McCue, T. Sea-Level Rise Technical Planning Assessment for the City of Satellite Beach; Florida Sea Grant: Gainesville, FL, USA, 2019; Available online: https://www.stetson.edu/other/iwer/media/Sea-Level%20Rise%20Technical%20Planning%20Assessment.pdf (accessed on 1 April 2025).
- USACE. ER 1100-2-8162 Incorporating Sea Level Change in Civil Works Programs; USACE: Washington, DC, USA, 2013; Available online: https://www.publications.usace.army.mil/Portals/76/Users/182/86/2486/ER_1100-2-8162.pdf (accessed on 1 April 2025).
- Satellite Beach. Code of Ordinances. § 30-555. Floor Level; Municode Library; Available online: https://library.municode.com/fl/satellite_beach/codes/code_of_ordinances?nodeId=PTIICICO_CH30LADERE_ARTVBURE_DIV8OTPR_S30-555FLLE (accessed on 1 April 2025).
- RI CRMC. What Is the CRMC? n.d. Available online: https://www.crmc.ri.gov/aboutcrmc.html#:~:text=It%20is%20authorized%20to%20formulate,the%20authority%20of%20the%20Council (accessed on 1 April 2025).
- RI CRMC. New STORMTOOLS Risk and Damage Assessment App Now Available. 2019. Available online: https://www.crmc.ri.gov/news/2019_1121_stormtools.html (accessed on 1 June 2025).
- RI CRMC. STORMTOOLS Design Elevation (SDE) Map Training Session. n.d. Available online: https://www.crmc.ri.gov/news/2018_1004_stormtools.html (accessed on 1 April 2025).
- RI CRMC. RI CRMC Coastal Hazard Application. 2019. Available online: https://ri-crmc-coastal-hazard-map-tool-crc-uri.hub.arcgis.com/ (accessed on 1 July 2025).
- RI CRMC. Shoreline Change SAMP Volume 1. 2018. Available online: http://www.crmc.ri.gov/samp_beach/SAMP_Beach.pdf (accessed on 1 July 2025).
- RI CRMC. RI CRMC FAQs. 2023. Available online: http://www.crmc.ri.gov/faqs.html.http://www.crmc.ri.gov/faqs.html (accessed on 1 July 2025).
- RI CRMC. RI Coastal Resources Management Council: About the CRMC. 2025. Available online: http://www.crmc.ri.gov/aboutcrmc.html (accessed on 21 February 2025).
- Berginnis, C. FEMA’s Proposed Rule on FFRMS: What Floodplain Managers Need to Know. 2023. Available online: https://www.floods.org/news-views/from-the-directors-desk/femas-proposed-rule-on-ffrms/ (accessed on 16 October 2023).
- FEMA. FEMA Federal Flood Risk Management Standard Policy Fact Sheet. 2024. Available online: https://www.fema.gov/sites/default/files/documents/fema_oehp_ffrms-general-fact-sheet_092024.pdf (accessed on 1 May 2025).
- FEMA. 44 CFR 9.6. 2024. Available online: https://www.ecfr.gov/current/title-44/part-9/section-9.6 (accessed on 1 May 2025).
- FEMA. FEMA Policy: Federal Flood Risk Management Standard (FFRMS): FEMA Policy 206-24-005. 2024. Available online: https://www.fema.gov/sites/default/files/documents/fema_floodplain-management_ffrms-policy_092024.pdf (accessed on 1 May 2025).
- IPCC. Climate Change 2014: Synthesis Report. In Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change; Pachauri, R.K., Meyer, L.A., Eds.; IPCC: Geneva, Switzerland, 2014; p. 151. [Google Scholar]
- USACE. Final Integrated General Reevaluation Report and Supplemental Environmental Impact Statement. In Brevard County, Florida, Hurricane and Storm Damage Reduction Project, Mid-Reach Segment; United States Army Corps of Engineers: Jacksonville, FL, USA, 2010; Available online: http://www.saj.usace.army.mil/Portals/44/docs/Planning/EnvironmentalBranch/EnvironmentalDocs/BrevardCountyMidReach06_FGRR_EIS_apr2011rev.pdf (accessed on 13 September 2018).
- NOAA. Federal Flood Standard Support Tool Introduction. April 2024. Available online: https://coast.noaa.gov/elearning/video/floodstandard/index.html (accessed on 1 July 2025).
- NOAA. Extreme Water Levels of the United States 1893–2010. 2013. Available online: https://tidesandcurrents.noaa.gov/publications/NOAA_Technical_Report_NOS_COOPS_067a.pdf (accessed on 1 June 2025).
- IPCC. Climate Change 2023: Synthesis Report. In Contribution of Working Groups I, II and III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change; Lee, H., Romero, J., Eds.; IPCC: Geneva, Switzerland, 2023; p. 184. [Google Scholar] [CrossRef]
- Wu, L.; Liu, Y. Identification of flood depth levels in urban waterlogging disaster caused by rainstorm using a CBAM-improved ResNet50. Expert Syst. Appl. 2024, 255, 124382. [Google Scholar] [CrossRef]
Factor/Criteria | Approach |
---|---|
Author/Entity | American Society of Civil Engineers (ASCE) |
Starting Elevation Measurement | Measured from FEMA BFE. |
SLR Scenario and Timeframe | Does not incorporate SLR projections. |
SLR Adjustment | N/A—freeboard is the primary elevation method used. |
Freeboard | Class 1 = 0′ Class 2 = 1′ (0.30 m) Class 3 = 2′ (0.61 m) Class 4 = 2′ (0.61 m) |
Design Flood Elevations |
* For ASCE Standard 24-14, the DFEs are the flood elevations shown on the map adopted by a community (if not using FEMA FIRMS). For buildings within Coastal High Hazard Areas, Coastal A Zones, and High Risk Flood Hazard Areas: the minimum elevation (listed above) is measured to the bottom of the lowest supporting horizontal structural member of the lowest floor. For buildings within all other Flood Hazard Zones: the minimum elevation is measured to the top of the lowest floor. |
Application | ASCE Standard 24-14 applies to new construction or substantial improvement of buildings and structures in flood hazard areas. |
Requirement or Recommendation | Required for all structures subject to building code requirements in flood hazard areas. |
Factor/Criteria | Approach |
---|---|
Author/Entity | Boston Planning and Development Agency (BPDA) |
Starting Elevation Measurement | Measured from FEMA BFE, which uses the Boston City Base (BCB) as their city-wide datum. NAVD88 can be converted to BCB by using a conversion factor of NAVD88 + 6.46 feet (1.97 m). |
SLR Scenario and Timeframe | Boston Harbor Flood Risk Model (BH-FRM) is a localized scenario that utilizes data from the U.S National Climate Assessment from [46]. The projection is set for the year 2070 for the “High” scenario. |
SLR Adjustment | 40″ (1.02 m) SLR adjustment (3.2′ (0.98 m) SLR + 2.5″ (0.06 m) land subsidence) |
Freeboard | 1′–0″ (0.30 m): all buildings—existing/retrofit 2′–0″ (0.61 m): planned/new construction or residential use, or uses, which are conditional within the overlay |
Design Flood Elevations | SLR-DFE = FEMA BFE + SLR Adjustment + Land Subsidence + Freeboard |
Application | Guides private development. Applies to all structures within the overlay zone (BH-FRM), which includes areas “anticipated to be flooded with a 1% chance storm event in 2070 with 40-inches (1.02 m) of sea level rise.” (includes 2.5″ (0.06 m) of land subsidence) |
Requirement or Recommendation | Required within the Coastal Flood Resilience Overlay District (CFROD); Section 25A-6 |
Factor/Criteria | Approach |
---|---|
Author/Entity | County of Kauaʻi |
Starting Elevation Measurement | Uses a sea level rise flood elevation (SLRFE) or FEMA FIRM BFE (if higher). Sea level rise flood elevation (SLRFE) is the individual depth above existing grade per grid unit provided by the County of Kauai Sea Level Rise Constraint District Viewer for both the high wave run up hazard and the passive flooding hazard when either of those are associated with 3.2 feet (0.98 m) of SLR occurring within this century. |
SLR Scenario and Timeframe | Uses Hawaiʻi’s sea level rise exposure area (SLR-XA), which includes passive flooding and annual high wave flooding, and coastal erosion is based on the high GHG emissions scenario (RCP8.5) used to model exposure to sea level rise 3.2 feet (0.98 m) by 2100. 2 |
SLR Adjustment | Flood depth indicated by SLRFE. |
Freeboard | 1′–0″(0.30 m): nonresidential 2’–0″(0.61 m): residential |
Design Flood Elevations | DFE = SLRFE or BFE + Freeboard (within the ST-CE and S-SLR) |
Application | Residential and non-residential new construction and major renovation within the S-SLR constraint district. |
Requirement or Recommendation | Required in the S-SLR, which is monitored through the use permitting process. |
Factor/Criteria | Approach |
---|---|
Author/Entity | City of Miami Beach |
Starting Elevation Measurement | Uses the highest point of adjacent road or above the crown of the nearest street (Flood Zone X) or FEMA BFE (Flood Zone A). |
SLR Scenario and Timeframe | “The years 2040 and 2070 were chosen because they represent a near- and long-term planning horizon, respectively. Two of the sea level rise scenarios (NOAA 2017 Intermediate–Low and NOAA 2017 Intermediate–High) were selected to comply with the Resilient Florida program. The City included a third scenario (NOAA 2017 High), which represents a more rapid rise in future sea level, as a more extreme scenario that can potentially be used for developing adaptation strategies for critical infrastructure (e.g., emergency facilities)”. |
SLR Adjustment | SLR Adjustment is not required, but the SLR Adaptation Plan 2 discusses SLR in the FFE. NOAA 2017 1: Intermediate–Low
Intermediate–High
High (critical)
|
Freeboard | Ref. [71], §54-35; 54-48; 54-51: 1′ (0.30 m) (min.)–5′ (1.52 m) (max.) Specifically: Flood Zone X: 1 foot (0.30 m) (min.) above the highest adjacent grade or above the crown of the nearest street; whichever is higher. Except seaward of the Coastal Construction Control Line and in Coastal A Zones, All Flood Zone A:
Flood Zone V and Coastal A Zone: meets all the above and in addition elevated on pilings or columns plus freeboard “no lower than 8.0 feet (2.44 m) NGVD (6.44 feet (1.96 m) NAVD), the crown of road or sidewalk plus one (0.30 m) foot, or the base flood elevation plus minimum freeboard whichever is higher”. |
Design Flood Elevations | DFE = BFE or highest adjacent grade or above the crown of the nearest street + (1′ (0.30 m)–5′ (1.52 m)) freeboard |
Application | Freeboard: all new construction and substantial improvements to existing construction as described in the Flood Zones above |
Requirement or Recommendation | Freeboard is required as described in the Flood Zones above 1. The SLR Adaptation Plan 2 discusses SLR in the FFE. |
Factor/Criteria | Approach |
---|---|
Author/Entity | City of Satellite Beach |
Starting Elevation Measurement | FEMA BFE or highest point of abutting street |
SLR Scenario and Timeframe | In their 2019 Sea-Level Rise Technical Planning Assessment [77], the city acknowledges data from the U.S. Army Corps of Engineers [78] “High” Scenario, which was derived from the U.S. Army Corps of Engineers Sea-Level Change Calculator (accessed 6 July 2018;). Projection through the year 2070. |
SLR Adjustment | SLR Adjustment is not required, but the Sustainability Action Plan V2 2 discusses SLR incorporated into future DFEs. USACE “High” Scenario (2070): 2.85 feet (0.87 m) above 1992 mean sea level (MSL). |
Freeboard | Commercial, Institutional and Industrial: minimum 18 inches (0.46 m) (current requirement)/30 inches (0.76 m) (recommended code modification) above the highest point of any abutting street. Residential: “above the dune vegetation on stilts/pilings to a minimum of three feet (0.91 m) above the BFE” if located east of Highway A1A. An owner may elevate the structure more than three feet (0.91 m) above the BFE as desired and if approved by the building official and in accordance with FEMA and NFIP standards. Variance: Property less than 15 feet (4.57 m) landward of the construction control line (CCL): 10 feet (3.05 m) above the BFE. |
Design Flood Elevations | =Street + 18–30″ (0.46–0.76 m) =BFE + 3′ (0.91 m) =BFE + 10′ (3.05 m) |
Application | “construction, reconstruction, modification, repair or replacement of principal or accessory structures or portions thereof for all properties located east of Highway A1A.” |
Requirement or Recommendation | Freeboard: required. Note recommended code modification (above). |
Factor/Criteria | Approach |
---|---|
Author/Entity | FFRMS Science Subgroup of the Flood Resilience Interagency Working Group of the National Climate Task Force. |
Starting Elevation Measurement | FEMA BFE is used for the Freeboard Value Approach (FVA) and 0.2% Annual Chance Flood Approach. |
SLR Scenario and Timeframe | Uses best-available science when using the Climate Informed Science Approach (CISA) (if climate science data is available). |
SLR Adjustment | Determined by climate science data (if CISA is available). |
Freeboard | For FVA (only):
|
Design Flood Elevations | If CISA is not available, the FVA is as follows:
|
Application | FEMA-funded projects involving new construction, substantial improvement, or repairs to address substantial damage. |
Requirement or Recommendation | Required for FEMA-funded projects. |
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Meguro, W.; Briones, J.I.; Teeples, E.; Fletcher, C.H. Establishing a Sea Level Rise-Adjusted Design Flood Elevation for Buildings: A Comparative Study of Methods. Water 2025, 17, 2376. https://doi.org/10.3390/w17162376
Meguro W, Briones JI, Teeples E, Fletcher CH. Establishing a Sea Level Rise-Adjusted Design Flood Elevation for Buildings: A Comparative Study of Methods. Water. 2025; 17(16):2376. https://doi.org/10.3390/w17162376
Chicago/Turabian StyleMeguro, Wendy, Josephine I. Briones, Eric Teeples, and Charles H. Fletcher. 2025. "Establishing a Sea Level Rise-Adjusted Design Flood Elevation for Buildings: A Comparative Study of Methods" Water 17, no. 16: 2376. https://doi.org/10.3390/w17162376
APA StyleMeguro, W., Briones, J. I., Teeples, E., & Fletcher, C. H. (2025). Establishing a Sea Level Rise-Adjusted Design Flood Elevation for Buildings: A Comparative Study of Methods. Water, 17(16), 2376. https://doi.org/10.3390/w17162376