Define “stormwater runoff.”

• A. Water from rain or melting snow that flows over the ground, potentially carrying pollutants
• B. Water that is collected in stormwater retention ponds
• C. Water that is directed to sewage systems during heavy rains
• D. Water that evaporates from surfaces after rainfall

Answer: (A)

Stormwater runoff refers to the water that originates from precipitation, such as rain or melting snow, when it flows over impervious surfaces like roads, sidewalks, and rooftops. During this process, the runoff can pick up various pollutants, including sediments, oils, chemicals, and other harmful substances from the surfaces it encounters. This is significant because it can lead to the contamination of local water bodies, posing risks to aquatic ecosystems and public health.

The other options describe related concepts but do not accurately define stormwater runoff. For instance, stormwater retention ponds are designed to manage and collect stormwater runoff to reduce flooding and filter pollutants, but they do not encompass the definition itself. Similarly, directing water to sewage systems during heavy rains pertains to drainage management rather than the definition of runoff. Lastly, evaporation describes a post-rain process that does not involve the movement of water across surfaces to carry pollutants, which is the core element of stormwater runoff. Thus, the correct definition clearly focuses on the flow of water over land and its potential to transport pollutants.