What is the main concern associated with impervious surfaces in urban areas?

The main concern associated with impervious surfaces in urban areas is increased flooding due to runoff. As cities develop, surfaces such as concrete and asphalt prevent water from seeping into the ground. This leads to higher volumes of water running over these surfaces during precipitation events, resulting in increased stormwater runoff. Without natural absorption into the soil, more water flows quickly into drainage systems, rivers, and streams, which can overwhelm these systems and lead to flooding.

Additionally, this excessive runoff can carry pollutants and debris into water bodies, which can degrade water quality. The lack of permeable surfaces exacerbates the natural water cycle, altering the flow and availability of water in urban environments. Therefore, managing impervious surfaces is crucial for controlling urban flooding and maintaining the health of local waterways.