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Sandbags have been the go-to flood mitigation choice for many years.
But they shouldn’t be.
There are countless images of sandbags stacked up around a building in which the water on the back side of the sandbag stack matches the level of the water on the front.
That's because sandbags are often improperly laid out, making them an ineffective protection measure. With climate change fueling the increased frequency and severity of devastating weather events around the world, solutions that are far easier to deploy and provide better resistance to flood seepage are needed.
For every degree Celsius of global warming, there is approximately 7% more water vapor in the air. More moisture in the atmosphere leads to heavier rainfall potential, increasing the likelihood and severity of inland flooding. More extreme and intensified precipitation linked to climate change has been responsible for over one-third of inland flood damages for almost four decades.
Flooding can lead to more weighted property losses, costly remediation, and restoration, and in some cases, total losses. In 2023 alone, 164 flood disasters were reported around the world. In the U.S. specifically, current models show a 26.4% increase in flood risk by 2050, with annual losses estimated at $32.1 billion.
Approximately 1.81 billion people worldwide are susceptible to flooding; in the U.S. 122 million are vulnerable to flooding. Whether you’re a municipality, property owner or regulator, flood risk mitigation planning is vital. Here are five reasons you need to replace sandbags with flood mitigation solution s that can withstand rapid flooding events:
- Sandbags require professional installation, which involves special configurations, with plastic sheathing interwoven between the bags to prevent leakage. When floodwaters are imminent, it’s highly unlikely that you’ll have instant access to someone qualified to build the wall correctly in quick time. More often in the face of peril, non-trained locals grab sandbags and stack them up as quickly as possible, and proper installation falls by the wayside.
- Large quantities of sandbags are needed to protect from an average flood. A standard door opening requires 225, 50-pound sandbags to create a three-foot-high barrier, and that’s just one door opening! Imagine encircling an entire building, or the length of a river — the sheer volume and weight of material is a liability all on its own. To put this in perspective, just 20 sandbags, weighing 50-pounds each (1,000-pounds in total) would be the maximum legal limit for a pickup truck to carry.
- Sandbags are not meant to be effective at stopping water flow — they are only expected to provide low-flow protection.
- Composed of material that cannot be fully recycled and contributes to microplastic buildup in the ocean, sandbags are not ecofriendly. Used sandbags often become contaminated after trapping and absorbing chemicals and sewage-laden floodwater, requiring special hazardous disposal post-flood. Contaminated ecosystems impact not only the marine life but the rivers and oceans as well.
- Sandbags are more expensive than you think. While the initial investment in a bag and contents is low, the lifecycle cost is high: it is not resilient or reusable and can deteriorate over time. The number of sandbags needed to build a wall and the disposal process make them more and more costly over time.
Relying on sandbags to mitigate floodwater damage assumes a high level of expense, exposure and risk that can be avoided with sustainable, effective flood mitigation options.
Solution: Temporary perimeter barriersWith the ineffectiveness of sandbags and the increased frequency, severity and pervasiveness of flood incidents around the world, innovation has spurred new developments for the design and implementation of flood barrier solutions.
These resilient and reusable barriers shield buildings from damaging floodwater. Made of metal or a specialized plastic with a metal support system, temporary perimeter barriers can easily be cleaned after use. They come in all shapes and sizes, with two general categories:
- Flexible, stackable tubes that are filled with water or sand and linked together. These can be emptied, cleaned, dried and stored.
- Removable flood walls with no material required to fill them, that get assembled before a flood event and can be easily demounted and stored afterwards.
Flood mitigation solutions must perform under extreme pressure so it’s crucial that your product’s functionality is independently certified and verified by scientific research and testing. Doing your due diligence here can be the difference between protection and loss. Here are some examples of the testing perimeter barriers go through when being evaluated against the requirements of ANSI/FM Approvals Standard 2510, the American National Standard for Flood Mitigation Equipment:
- Full-scale assembly testing for the ability to control rising waters resulting from both riverine- and rainfall-related flood conditions.
- Assessment of leakage at various water levels to confirm that it can only leak minimally, if at all.
- Resistance to dynamic wave action
- Resistance to floating debris impact
- Overall performance and robust component testing to verify functionality under conditions consistent with today’s climate risks, throughout their expected lifetime.
FM Approved flood mitigation systems have met the loss prevention requirements defined by the American National Standard for Flood Mitigation Equipment. Recognized and respected worldwide, ANSI/FM 2510 Approved certification signals that products will perform under the toughest flood conditions.
Visit the Approval Guide to gain access to tens of thousands of FM Approved products and services with essential engineering data, technical information and use categorization. FM Approved flood mitigation systems are now available in North America, Europe, Asia and, increasingly, worldwide.