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Listen to part of a lecture in an environmental science class. Professor: Today we're discussing the role of wetlands in flood control. Many people think of wetlands as useless, swampy areas, but they actually act like natural sponges. When rivers overflow, wetlands absorb excess water, slowing its flow and reducing the risk of flooding downstream. This is especially important in coastal areas, where wetlands can also buffer against storm surges. However, over the past century, urban development has led to the draining of nearly half of the world's wetlands. This has increased flood risks. For example, in the Mississippi River basin, the loss of wetlands contributed to the severity of the 1993 floods. Now, some cities are restoring wetlands as a cost-effective flood defense. Unlike concrete levees, wetlands are self-maintaining and provide wildlife habitat. But restoration takes time, and we must also consider the effects of climate change, which may alter rainfall patterns. So, while wetlands are not a complete solution, they are a vital part of a comprehensive flood management strategy.