Permanent floodwalls are permanent barriers constructed on your site to prevent water from coming into contact with your building. Floodwalls must be specially designed to resist the pressure caused by the floodwater acting on one side of the wall. While floodwalls are often constructed of reinforced concrete, they can be faced with more attractive building materials or integrated into the landscaping of the site to be more attractive and less conspicuous.
One of the main advantages of permanent floodwalls is that the building does not have to be disturbed at all.
The main disadvantage of permanent floodwalls is that you need sufficient extra land around your building on which to build the walls.
- Some localities restrict the construction of individual floodwalls. It is important to check your local zoning/building code to determine if it is possible to build floodwalls on your property.
- If the water levels rise above the highest expected flood level, floodwalls can overturn and fail.
- Floodwalls that are constructed close to property lines can negatively impact local drainage patterns, which may increase flooding for your neighbors.
- Depending on how floodwater encroaches on your site, you may only need to construct floodwalls in a certain area, rather than around your entire building.
- Any access openings in the floodwall need to be closed by temporary barriers during a flood event.
- An option similar to a permanent floodwall is a levee, which is a barrier constructed out of soil, but levees typically need special permits to be constructed and take up much more space than floodwalls.
- Louisiana State University Agricultural Center, Floodwalls: www.lsuagcenter.com/NR/rdonlyres/7A01F7C8-703B-47D1-BCCD-63CD0A57721F/2995/pub2745Floodwall6.pdf
- Floodwalls and Flood Embankments: evidence.environment-agency.gov.uk/FCERM/Libraries/Fluvial_Documents/Fluvial_Design_Guide_-_Chapter_9.sflb.ashx
- Homeowner’s Guide to Retrofitting, Chapter 8: Barriers: www.fema.gov/media-library-data/1404150139578-ee3a6bc655a236dceba367adcfb8c982/FEMA_P312_Chap_8.pdf