Nghe TOEFL

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Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we're discussing the concept of 'green infrastructure' in urban planning. Unlike traditional gray infrastructure—think concrete pipes and treatment plants—green infrastructure uses natural systems to manage stormwater. For example, permeable pavements allow rainwater to soak into the ground, reducing runoff. Green roofs, covered with vegetation, absorb rainfall and also provide insulation, cutting energy costs. Another key element is urban wetlands, which act as natural filters, removing pollutants before water reaches rivers. But there are challenges. Retrofitting existing cities is expensive, and maintenance requires specialized knowledge. Some critics argue that the benefits are overstated, especially in arid regions where water is scarce. However, a recent study in Portland showed that green infrastructure reduced combined sewer overflows by 25% over five years. This suggests that, despite costs, long-term savings in flood damage and water treatment can be significant. So, the question isn't whether to adopt it, but how to adapt it to local conditions.