TOEFL Listening

🎧 Listening Transcript

Listen to part of a lecture in an environmental science class. The professor is discussing the role of wetlands in flood control. Professor: Now, many people think of wetlands as just muddy, unproductive areas, but they actually provide critical ecosystem services. One of the most important is flood mitigation. When rivers overflow, wetlands act like natural sponges, absorbing excess water and slowly releasing it over time. This reduces the peak of the flood wave, which can prevent downstream damage. For example, in the Mississippi River basin, studies have shown that the loss of millions of acres of wetlands has contributed to more severe flooding in cities like St. Louis. Historically, flood control strategies focused on building levees and dams, but engineers now recognize that restoring wetlands is often more cost-effective and sustainable. However, wetland restoration requires space—land that might otherwise be used for agriculture or development. So there is a trade-off. But as climate change increases the frequency of extreme weather events, the natural flood protection provided by wetlands is becoming increasingly valuable. Some cities are even creating artificial wetlands as a green infrastructure solution. This approach not only reduces flood risk but also improves water quality and provides habitat for wildlife.