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What Is a Floodplain?

A floodplain is a low-lying area where a waterway may overflow. Learn about floodplain zones and the difference between a floodway and a floodplain.

Is it risky to live on a floodplain? (Possibly!) What should you do if you do? (Buy flood insurance and more.) How were floodplains created? What benefits do they offer to the natural world and its inhabitants? If you have questions about floodplains, you’ll find your answers here.

Whether you live on or near a floodplain, are planning to move near one, or just want to learn more, keep reading for the details about this natural landscape.

A Floodplain Defined

A floodplain is a naturally occurring, low-lying area surrounding a waterway that regularly overflows. Weather patterns and shifting waterways over hundreds or thousands of years create natural floodplains. Water flows through the floodplain, which allows the sediment to settle, forming piles along the sides, known as levees. As a result, the floodplain features a flat area, or streambed, with steep edges on the perimeter, also known as stream banks.

Depending on the location, a floodplain can be a minor component of a landscape or the primary feature. Some are so small they may not show up on a map, while others are very large, like those that surround the Mississippi River.  

Floodplains offer myriad benefits to the natural world and humans, including:

  • Flood protection
  • Enhanced water quality (floodplains act as natural water filters)
  • Replenished underground water sources
  • Improved wildlife habitat
  • Rich soil for flood-tolerant crops

Types of Floodplains

According to the Federal Emergency Management Association (FEMA), there are three different types of floodplains:

  1. The floodway – The channel of the watercourse and adjacent land that fills with flowing water during a flood event.
  2. The 1% (100-year) floodplain – The land covered in floodwater during a flood event that has only a 1% chance of happening each year, or a 26% chance over a span of 30 years. This is considered a high-risk floodplain zone.
  3. The .02 percent (500-year) floodplain – The land covered in floodwater during an event that has a 0.2% chance of happening each year, or a 6% chance over a span of 30 years. This is considered a moderate-to-low-risk floodplain zone.

Floodplain vs. Floodway: What’s the Difference?

The terms floodplain and floodway sound similar, but they have different designations and purposes. A floodway lies within the floodplain boundary and must be completely clear of buildings and structures to allow the floodwaters to pass during a flood event. Buildings in a floodway could alter the flood watercourse, increasing flood risk to surrounding areas. On the other hand, FEMA allows certain buildings and structures to be erected in specific parts of a floodplain, including the areas designated as the 1% and 2% floodplains.

Risks of Owning a Home or Business in a Floodplain Zone

Floodplain zones help builders and homeowners determine the level of risk associated with building in or inhabiting areas near a waterway (lake, river, stream, creek). Insurance agents use flood maps to identify the zones, which guide them in determining flood insurance requirements and coverage costs.

You can experience a devastating flood event, even if you live in a low-risk zone. The National Flood Insurance Program (NFIP) states that more than 20% of claims come from areas outside of high-risk flood zones, including homes that would be affected by a dam failure that may be miles and miles away. Whether you live in a high- or low-risk floodplain zone, purchasing flood insurance is crucial to protect against financial losses resulting from floods, even if not required. Even a couple of inches of water can lead to several thousand or tens of thousands of dollars of damage.

If you choose to live in a floodplain zone, there are some important considerations to make:

  • Purchase appropriate flood insurance (even if you aren’t required to by law).
  • Use flood-resistant building materials in the home, such as laying tile instead of carpet, especially in the basement.
  • Install flood vents, which allow the waters to flow through the vents and drain out.
  • Elevate your property so the lowest floor is higher than the flood elevation level as identified on the flood map.
  • Store belongings that would be adversely affected by water in a high location or a waterproof box to keep them safe from floodwaters.
  • Have a plan in place for water damage restoration that you can utilize immediately following a flood event. Addressing water damage right away (within 24-48 hours) minimizes damage and avoids common post-flood problems like mold growth.

Choose Rainbow for Water Damage Restoration in a Floodplain Zone

If you experience a damaging flood event in a floodplain zone, your local Rainbow International is ready to help. As IICRC-certified water damage restoration professionals, our experienced technicians provide remediation and restoration services to get your home or business back to its pre-loss condition. Call (855) 724-6269 now for 24/7 emergency service or request an appointment online

If you close your business after a flood or other natural disaster, there are steps to take before re-opening, like flushing water lines. Learn how to flush your water lines from our friends at Mr. Rooter® Plumbing. Mr. Rooter is a fellow member of the Neighborly® family of trusted home service brands.