Certified Storm Water Operator Practice Exam

Urban runoff is primarily characterized by the flow of water from urbanized areas that has picked up various contaminants as it moves over impervious surfaces such as roads, rooftops, and parking lots. The correct answer highlights the significant impact of urban runoff, which often carries pollutants like oil, heavy metals, nutrients, and sediments into nearby water bodies. This influx of contaminants leads to an increase in pollution levels, which can adversely affect aquatic ecosystems, water quality, and human health.

In urban settings, the lack of natural filtration mechanisms—like vegetation and soil that normally help purify water—means that when it rains, stormwater runoff directly enters rivers, lakes, and oceans, bringing these pollutants with it. The consequence is that water bodies experience heightened levels of pollutants, which can cause algae blooms, harm aquatic life, and degrade overall water quality.

While enhancing groundwater recharge and decreasing water temperature may occur under certain conditions, urban runoff typically disrupts natural processes, preventing these positive effects. Similarly, improvement in water clarity is unlikely as increased pollution generally results in lower clarity due to particulate matter and nutrients causing turbidity.