Real-world examples of the role of wetlands in flood prevention

Starting with real examples of the role of wetlands in flood prevention

Most school projects explain how wetlands work in theory. The stronger projects start with real examples of the role of wetlands in flood prevention and then build experiments around them. Think of your science fair board as telling this story: Here’s what wetlands did in the real world; here’s how I tested the same idea in a model.

Scientists often compare areas with healthy wetlands to nearby areas where wetlands were drained or filled. During big storms, the wetland-rich areas usually have lower flood peaks and less damage. Your project can mimic this by comparing a model landscape with a wetland to one without it.

Below are several of the best examples of the role of wetlands in flood prevention you can reference, plus ideas on how to turn each one into a testable question.

River floodplain wetlands: classic examples of the role of wetlands in flood prevention

Floodplain wetlands sit next to rivers and spread out during high water. They slow the flow, store water temporarily, and release it later. Some of the clearest examples of the role of wetlands in flood prevention come from large river systems.

Upper Mississippi River floodplains (U.S.)

Along the Upper Mississippi River, bottomland forests and marshes used to cover huge areas. Over the past century, many of these wetlands were drained or cut off by levees. Studies by the U.S. Geological Survey and the U.S. Army Corps of Engineers have shown that where floodplain wetlands remain connected to the river, they can store significant volumes of floodwater and reduce downstream peak flows.

For your project, you can cite how restoring floodplain wetlands in the Mississippi basin is considered a cost-effective way to reduce flood risk, especially as heavier rainstorms become more common with climate change. The examples of the role of wetlands in flood prevention here are clear: towns with wider natural floodplains often see lower flood heights than upstream or downstream areas boxed in by levees.

Project angle: Build a long stream table in a tray. In one version, let the water spread into a broad, shallow “wetland” zone made of soil and sponge. In the other version, confine the stream with clay “levees.” Measure how high the water rises and how fast it moves through each setup when you pour the same amount of water.

The Danube and Rhine floodplain restorations (Europe)

In Germany and neighboring countries, parts of the Rhine and Danube rivers have had floodplains reconnected or restored since the 1990s. Government agencies report that these wetlands can store millions of cubic feet of floodwater, helping to reduce flood peaks downstream.

These are strong international examples of the role of wetlands in flood prevention because they involve before-and-after data: when floodplains were cut off, flood peaks rose; when some floodplain wetlands were restored, peak flows dropped slightly and flood timing shifted.

Project angle: Use online river flow data (hydrographs) from before and after floodplain restoration projects. Graph peak flows and compare. In your discussion, connect your model wetland results to these real-world patterns.

Coastal wetlands: examples include storm surge and hurricane protection

Coastal marshes and mangroves act as a buffer between the ocean and inland areas. Some of the best examples of the role of wetlands in flood prevention come from hurricane and storm surge studies.

Louisiana coastal marshes and Hurricane Katrina

Before Hurricane Katrina in 2005, Louisiana had already lost a large share of its coastal wetlands due to subsidence, sea-level rise, and human development. Research by the U.S. Geological Survey and other agencies has shown that intact marshes can reduce storm surge heights and wave energy as water moves inland.

Several studies estimate that every few miles of healthy marsh can reduce storm surge by measurable amounts. While the exact numbers vary by location and storm, these examples of the role of wetlands in flood prevention help explain why Louisiana is now investing billions in coastal restoration.

Project angle: Create a small wave tank with a fan or by dropping water from a height. Test how far “waves” travel and how high they splash on a “shoreline” with and without a strip of sponge or artificial grass representing a marsh. Measure splash height on a back wall to represent flooding.

Mangroves and cyclone flooding in South and Southeast Asia

Outside the U.S., mangrove forests in countries like India, Bangladesh, and the Philippines provide powerful examples of the role of wetlands in flood prevention. After major cyclones, villages protected by mangroves often report fewer deaths and less flood damage than unprotected villages.

Peer-reviewed studies have calculated the economic value of mangroves in terms of flood protection, sometimes in the tens of thousands of dollars per acre in avoided damages. These real examples show that wetland trees and roots physically block and slow storm surges.

Project angle: If you want to highlight global science, compare data from two coastal regions: one with mangroves or marshes and one with mostly bare shoreline. Use maps and satellite images to show wetland width, then compare reported flood depths from a specific storm.

Urban and suburban wetlands: everyday examples of flood reduction

Not all examples of the role of wetlands in flood prevention come from huge rivers or hurricanes. Many cities are now treating wetlands as green infrastructure—nature-based systems that manage stormwater.

Urban wetland parks and stormwater basins

Cities like Portland, Oregon; Denver, Colorado; and Charlotte, North Carolina have restored or built wetland parks that double as flood control features. During heavy rain, these wetlands temporarily fill with water instead of letting it rush straight into storm drains and creeks.

The Environmental Protection Agency (EPA) highlights such projects as examples of nature-based solutions that reduce both flooding and water pollution. These urban wetlands are real, measurable examples of the role of wetlands in flood prevention on a neighborhood scale.

Project angle: Use local rainfall data from your city and a simple runoff calculator (many are available online) to estimate how much water a small urban wetland could store compared with a paved parking lot of the same size. Then build a model using two trays—one filled with soil and plants, one with plastic or foil—to test your estimates.

Schoolyard or community wetlands

If your school or community has a rain garden, detention basin, or small wetland, you already have a live case study. During storms, you can measure how quickly water levels rise and fall, and compare that with nearby streets or fields.

These small systems might not make national news, but they are personal, local examples of the role of wetlands in flood prevention that judges love to see in a science fair project.

Project angle: Mark a measuring stick in the wetland (with permission) and record water depth after rain events. Compare it to the depth in a roadside ditch or low spot without plants. Relate your observations to how larger wetlands behave during floods.

How wetlands actually reduce floods: science you can test

To turn these real-world stories into a strong science fair project, you need to show how wetlands work. Most examples of the role of wetlands in flood prevention come down to a few key processes you can model.

Storage: wetlands as natural sponges

Wetlands store water in three main places:

• In the soil, especially if it is rich in organic matter.
• In the spaces between plant roots.
• On the surface as shallow standing water.

During a storm, this storage capacity slows the rise of water levels downstream. Many studies measure “peak flow,” the highest flow during a storm. Areas with wetlands often have lower peak flows for the same amount of rainfall.

In your model, you can measure how much water a wetland tray can hold before it starts to overflow compared with a bare-soil or paved tray. This directly connects your experiment to the examples of the role of wetlands in flood prevention you’ve read about.

Slowing flow: friction from plants and rough ground

Tall grasses, shrubs, and uneven ground in wetlands create friction that slows moving water. As water slows down, it spreads out and has more time to soak into the ground.

You can test this by comparing water flowing over a smooth surface (like plastic) to water flowing through a tray packed with sponges, gravel, and artificial plants. Time how long it takes for the same volume of water to travel from the top of the tray to the bottom.

Spreading out floods: lowering and delaying the peak

One reason scientists value wetlands is that they often delay the peak of a flood. That delay can give people time to evacuate or move valuables. It can also reduce the chance that multiple tributaries peak at the same time.

When you graph your experiment data, look for these patterns:

• Does the wetland model reach peak water height later than the non-wetland model?
• Is the maximum height lower when a wetland is present?

These graphs mirror the hydrographs used in professional flood studies and connect your work directly to published examples of the role of wetlands in flood prevention.

Designing a science fair project around wetlands and floods

To turn all of this into a strong project, frame your work as a testable question inspired by real examples. Here are a few research questions you might use or adapt:

• How does the size of a wetland area affect peak water level in a model watershed?
• How does vegetation density in a model wetland change the speed of floodwater?
• How does soil type (sand vs. organic-rich soil) affect how much water a wetland can store?

Then, connect your results to specific examples of the role of wetlands in flood prevention you’ve cited:

• If your model shows that doubling wetland area lowers peak water height by a certain percentage, compare that pattern to case studies from the Mississippi or Rhine.
• If denser vegetation slows water more, relate that to mangrove or marsh studies showing reduced storm surge behind thick vegetation belts.

Use graphs, tables, and clear labels. Judges appreciate when you tie your small-scale model to large-scale real examples.

Climate change and why wetland flood protection matters more in 2024–2025

Recent climate reports from agencies like NOAA and the IPCC show that heavy rainfall events are becoming more frequent and intense in many regions. That means more flash floods, more river floods, and more coastal flooding on top of rising sea levels.

Because of this, governments and scientists are paying fresh attention to examples of the role of wetlands in flood prevention:

• In the U.S., federal and state agencies are funding wetland restoration as a nature-based flood defense.
• Internationally, organizations highlight wetlands as part of climate adaptation strategies.

For your project, this is good news: your topic is very current. You can mention that your experiment helps explain how a real climate adaptation strategy works.

FAQ: examples of wetlands and flood prevention for your project

Q: What is one simple example of the role of wetlands in flood prevention I can explain quickly?
A: A classic example is a river floodplain wetland. When a river rises after heavy rain, the water spreads into nearby wetlands instead of staying trapped in a narrow channel. The wetland stores some of that water and slows it down, so downstream towns see lower and later flood peaks.

Q: Are there local examples of the role of wetlands in flood prevention in U.S. cities?
A: Yes. Many cities now use constructed wetlands and wetland parks to manage stormwater. During intense rain, these wetlands temporarily hold runoff that would otherwise flood streets and overwhelm storm drains. City and EPA reports often highlight these projects as successful examples of nature-based flood control.

Q: How can I use real examples of the role of wetlands in flood prevention without turning my project into a research paper only?
A: Use real examples as your background and inspiration. Pick one or two case studies—such as coastal marshes in Louisiana or mangroves in Asia—and briefly summarize how they reduced flooding. Then design a small experiment that tests the same idea on a model scale. Your data plus those examples make a strong combination.

Q: Do all wetlands reduce floods, or are there exceptions?
A: Most wetlands reduce floods, especially when they are connected to rivers or coasts. However, if a wetland is very small compared with the size of the watershed, its impact on big floods might be limited. Also, if wetlands are cut off by levees or roads, they may not be able to store floodwater effectively. This is why many restoration projects focus on reconnecting wetlands to rivers.

Q: Where can I find more real examples of the role of wetlands in flood prevention for my science fair background section?
A: Look for case studies and fact sheets from government and university websites. Search for terms like “wetland flood storage,” “floodplain restoration,” or “coastal marsh storm surge reduction” on .gov or .edu sites. These sources often provide graphs, maps, and summaries that are easy to adapt for a science fair board.

If you build a clear model, collect careful data, and connect your findings to these real-world examples of the role of wetlands in flood prevention, you’ll have a science fair project that’s not only scientifically solid but also directly relevant to the floods people are dealing with today.