การฟัง TOEFL

🎧 บทถอดเสียง

Listen to part of a lecture in an environmental science class. The professor is discussing the impact of urban development on local ecosystems. "Now, when we talk about urban development, we often focus on the immediate loss of green spaces. But there's a subtler, yet equally important, effect on watersheds. As cities expand, they replace permeable soil with impermeable surfaces like asphalt and concrete. This means rainwater can no longer soak into the ground. Instead, it runs off quickly, carrying pollutants—oil, heavy metals, and fertilizers—into nearby rivers and streams. This rapid runoff also reduces groundwater recharge, which can lower water tables and affect local vegetation. However, there are solutions. For example, green infrastructure, such as rain gardens and permeable pavements, mimics natural processes by capturing and filtering runoff at its source. These measures not only improve water quality but also help recharge aquifers. So, while urban growth is inevitable, its negative impacts on water systems can be mitigated through careful planning and design." What is the main point the professor makes about urban development?