Dry Floodproofing

Accommodate
Written By Frank Hangler

Dry floodproofing is a practice of utilizing waterproof membranes and other types of sealants to prevent floodwater from entering a building.[^1] It may also include the installation of watertight seals over windows and doors, diversion of water using berms and mounds, or the establishment of minimum setback regulations for building construction. [^3] [^5] [^6] [^7] [^11] The work required to dry flood-proof a structure could be determined through a risk assessment following local government requirements, guidelines, or policies.[^2] [^3] Depending on the complexity of the requirements, dry floodproofing is usually a cost-effective retrofit. Dry floodproofing contributes to a reduction in potential flood damage by decreasing the probability of inundation to the interior of a building. Dry floodproofing is a useful alternative as a flood mitigation measure where the relocation or elevation of a building is not a plausible cost-effective or technically feasible alternative. [^12]

Types of dry floodprofing

  • Continuous impermeable walls include sealing the exterior walls of a building, utilizing waterproof membranes that are impermeable and that have the potential to strengthen the walls.
  • Flood resistant interior core areas include important components and areas of a building that are made flood-resistant instead of dry proofing the entire footprint of the building.
  • Flood shields are watertight structures that close any opening in a building’s exterior walls to prevent the entry of floodwater. [^12]
  • Internal drainage systems are used to remove water that might seep into a building through fissures or other openings that comprise a flood protection system.

✓ Benefits

  • Builds resilience by providing a secondary means of protection to dikes
  • Improves flood protection when other measures are difficult to implement due to space constraints
  • Less costly when compared to other methods of flood retrofitting
  • The implementation does not require additional land space [^11]
  • Can be used to bring non-residential structures into compliance with floodplain management regulations and codes [^12]

✗ Challenges

  • Will not minimize the impacts of high-velocity water flow and wave action on a building or structure [^11]
  • May be difficult to apply to existing buildings and infrastructure
  • May not always lead to an improvement in flood mitigation that aligns with existing floodplain management bylaws [^11]
  • May fail, if flooding exceeds the level of flood protection intervention

Example projects

Citations

<! data-preserve-html-node="true"-- Regular citations --> [^1]: The Arlington Group Planning Architecture Inc., et al. Sea Level Rise Adaptation Primer. pp. 62. https://www2.gov.bc.ca/assets/gov/environment/climate-change/adaptation/resources/slr-primer.pdf [^2]: Ibid, 62. [^3]: FEMA. Selecting Appropriate Mitigation Measures for Floodprone Structures. 1 Mar. 2007, pp. 1. https://www.fema.gov/media-library-data/20130726-1608-20490-9182/fema_551_ch_07.pdf [^4]: HafenCity Hamburg GmbH. “Flood-Secure Bases Instead of Dikes: Safe from High Water in HafenCity.” HafenCity, https://www.hafencity.com/en/concepts/flood-secure-bases-instead-of-dikes-safe-from-high-water-in-hafencity.html.
[^5]: Ibid. [^6]: Ibid. [^7]: Flood Construction Levels and Setbacks for Farm Building Situations. British Columbia Ministry of Agriculture, July 2008, pp. 2. https://www2.gov.bc.ca/assets/gov/farming-natural-resources-and-industry/agriculture-and-seafood/farm-management/structures-and-mechanization/823400-2_flood_const_levels_and_setbacks.pdf. [^8]: Ibid, 2. [^9]: Ibid, 3-4. [^10]:
Ibid, 5. [^11]: FEMA (n.d) Chapter 7 dry floodproofing. Retrieve from https://www.fema.gov/media-library-data/20130726-1608-20490-9182/fema_551_ch_07.pdf [^12]: FEMA (n.d). Dry Floodproofing Measures. https://www.fema.gov/media-library-data/06dabddadc3887f91906172d863749ab/P-936_sec3_508.pdf

<! data-preserve-html-node="true"-- Images --> [^i1]: Figure 1. FEMA (n.d) Chapter 7 dry floodproofing. Retrieve from https://www.fema.gov/media-library-data/20130726-1608-20490-9182/fema_551_ch_07.pdf [^i2]: Figure 2. Wikimedian Commonsé (2020). File:Hamburg, HafenCity, Bebauung am Sandtorkai -- 2016 -- 3036.jpg

Frank Hangler
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