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: Today we're going to talk about wetlands, which are often called nature's sponges. Now, wetlands are areas where water covers the soil, either permanently or seasonally. They include marshes, swamps, and bogs. One of their crucial functions is flood control. When heavy rain falls, wetlands can absorb a significant amount of water, slowing its flow into rivers and streams. This reduces the peak of floodwaters downstream. For example, in the Mississippi River basin, studies have shown that the loss of wetlands has contributed to more severe flooding. But there's more. Wetlands also filter pollutants, as plants and soil trap sediments and break down excess nutrients. Moreover, they provide habitat for countless species. Unfortunately, over half of the world's wetlands have been drained or filled for agriculture and development. Conservation efforts are now focusing on restoring these areas, not just for wildlife, but for the flood protection they offer to human communities. So, when we think about flood defenses, we should consider green infrastructure like wetlands, not just concrete levees.