How can urbanization impact stormwater runoff?

• A. It decreases impervious surfaces leading to less runoff
• B. It increases impervious surfaces leading to more runoff and potential pollution
• C. It has no effect on runoff
• D. It leads to more vegetation cover

Answer: (B)

Urbanization significantly impacts stormwater runoff primarily by increasing impervious surfaces such as roads, parking lots, and buildings. These surfaces do not absorb water like natural landscapes do, causing rainwater to flow over them quickly rather than soaking into the ground. As a result, this increased runoff can lead to higher volumes of water entering storm drains and water bodies in a shorter time frame, which heightens the risk of flooding and erosion.

Moreover, urban stormwater runoff often carries a variety of pollutants, including oils, heavy metals, and sediments from roads and buildings, as well as debris and litter. These contaminants can degrade water quality in nearby streams, rivers, and lakes, posing threats to aquatic life and ultimately impacting human health and the environment. Therefore, the correlation between increased impervious surfaces due to urbanization and the resultant rise in both the quantity and pollution load of stormwater runoff is critical to understanding the ecological challenges posed by urban development.