Levees and walls: two typical barriers against floods.

How to Find the Best Option to Mitigate Floodprone Structures

How do you find the best option to mitigate floodprone structures? What will work best in your particular situation? FEMA discusses many different options in an interesting brochure titled “Selecting Appropriate Mitigation Measures for Floodprone Structures.”

The intended audience is for state and local officials. But don’t let that scare you. This brochure can also help home- and business owners think about their options, the pros/cons of each, their relative costs, and suitability for a particular location.

The first part of the 198-page document deals with how to use something called FEMA’s National Tool. It collects information from a variety of different sources. Planners use the data to create a “scorecard” that helps rank the alternatives.

Flood-Mitigation Alternatives Discussed

The major types of alternatives discussed in the brochure include:

  1. Drainage Improvements
  2. Barriers
  3. Wet Floodproofing
  4. Dry Floodproofing
  5. Elevation
  6. Relocation
  7. Acquisition (Buyouts)

Helpful Screening Questions

Chapter 3 contains a variety of screening questions designed to help determine the “fit” of each option for a particular location. For instance, to name a few, “What is the…”

  • Structure type
  • Condition of the structure
  • Foundation type
  • Number of stories
  • Building footprint

Example of Material in Typical Chapter

The meat of the discussion starts after that. The document contains a chapter on each of the seven major options and sub-options within them.

At a minimum, these chapters explain how flood professionals are trained to evaluate options and make recommendations in your situation.

While FEMA’s text is aimed at professionals, it’s well written, clear, and easy to understand. I won’t elaborate on each chapter, but will give you an example – Chapter 5: Barriers.

Levees and walls, two of many barriers against flooding discussed in Chapter 5.

Other sub-options include berms and temporary barriers (inflatable, floatable, and water filled).


  • They keep floodwaters out of the house and prevent flood damage
  • They require no significant changes to structures.


  • Barriers may not bring a substantially damaged structure into compliance with local floodplain management ordinances
  • Cost may be prohibitive
  • Large area needed for construction
  • Need for maintenance
  • Can affect local drainage, making flooding worse for others.

Whether they’re suitable in your situation will depend on:

  • The depth of flooding
  • Height of the barrier needed
  • Local building codes
  • Type of foundation (i.e., these don’t work well with basements)
  • Soil conditions (load-bearing capacity and permeability)
  • Duration of floods
  • Costs
  • Requirements for human intervention
  • Annual maintenance
  • Access to structure during normal times
  • Escape from structure if barrier is overtopped during an extreme event
  • Interior drainage (what happens if water starts filling in behind the barrier)

The brochure contains lucid and thought provoking discussions on each of these issues. If you start exploring such barriers, this brochure will help you plan discussions with contractors.

Highly Recommended

And so it goes for each of the other major types of mitigation found in other chapters. This is a valuable resource for anyone considering a major investment. It won’t help you make a final decision. But it will help you make a more intelligent decision.

So if you’re trying to find the best option to mitigate floodprone structures, click here.

Posted by Bob Rehak on 2/18/2023

1999 Days since Hurricane Harvey