For the past 30 years, freshwater flooding in the US resulted in an average of $8.2bn loss[1] per year, though this average accounts for an upward trend recently. According to a 2018 study titled “Estimates of present and future flood risk in the conterminous United States” published in Environmental Research Letters, nearly 41 million people live within the floodplain nationally, and damage estimates from a 100-yr flood is $1.2 trillion. With sea-level rise, the impacts of flooding will continue to grow with more people getting affected and the damage estimates increasing (Wing, 2018). The following graph shows future flooding trends and the expected damage.
Where to Start
You can make a difference in mitigating the flood impacts on buildings by adding a few simple steps to your design process.
- Carry out high-level studies to determine if the project location is in a flood plain or can be affected by floods in the future. The following link provides flood maps for various locations for current and future climate scenarios. https://coastal.climatecentral.org/. In addition, FEMA flood maps indicate flood hazard areas for various locations.
- It is recommended that projects in flood risk zones involve qualified consultants or engineers who can carry out accurate flood modeling and (a) identify Design Flood Elevation (DFE) and (b) identify all critical assets below the design flood elevation. (Tak, 2019). Design Flood Elevation (DFE) refers to the elevation that is used for determining the elevation of building elements in new construction[2]. Critical assets include components that support the function of the building during emergencies and otherwise.
- The Resilience Design Toolkit that is compiled by AIA and HKS recommends performing a Benefit Cost Analysis for each of the identified strategies for the project. The analysis yields a Benefit Cost Ratio (BCR) which is the ratio of the initial costs to the savings during perilous events. If the BCR is one or more, the strategy can be considered beneficial.
What Designers Can Do Now
Click HERE to see the various strategies that designers can use to “flood-proof” the building.
Tools and Resources
- https://coastal.climatecentral.org/.
- FEMA Flood maps
- https://coast.noaa.gov/stormwater-floods/analyze/
- https://buildingscience.com/documents/building-science-insights/bsi-128-designing-floods#:~:text=All%20flood%20risk%20is%20reduced,foundations%20and%20crawl%20space%20foundations.
- https://longislandsoundstudy.net/our-vision-and-plan/thriving-habitats-and-abundant-wildlife/living-shoreline-projects/
- https://coastalscience.noaa.gov/
- https://opc.ca.gov/2024/01/draft-slr-guidance-2024/#:~:text=Key%20takeaways%20from%20the%20updated,in%20the%20next%2030%20years.
- FEMA Technical Bulletin 2: Flood Damage Resistant Material Requirements
- FEMA’s Technical Bulletin 4: Elevator Installation for Buildings Located in Special Flood Hazard Areas
- Resilient Building Design Guidelines by the City of Hoboken
- Resilience Design Toolkit by AIA and HKS
- Flood Damage Resistant Materials Requirement- FEMA Technical Bulletin 2
- Designing for Natural Hazards: A Technical Guide for Builders and Developers- Volume 2 Water
[1] (Wing, 2018)
[2] https://fontanarchitecture.com/base-flood-elevation-design-flood-elevation/
[3] Resilience Design Toolkit, HKS and AIA
[4] https://buildingscience.com/documents/building-science-insights/bsi-128-designing-floods#:~:text=All%20flood%20risk%20is%20reduced,foundations%20and%20crawl%20space%20foundations.
[5] Resilient Building Design Guidelines by City of Hoboken