A buffer zone is defined as?

• A. A concrete barrier around a water body.
• B. Vegetation near water that slows runoff and absorbs pollutants.
• C. A deep trench to drain water.
• D. A chemical treatment area.

Answer: (B)

Buffer zones protect water quality by using vegetation to filter runoff from surrounding land. A strip of plants along a stream or lake slows and traps sediments, absorbs nutrients and other pollutants with roots and soil, and helps keep the shoreline stable to prevent erosion. Because of these filtering and uptake functions, a vegetated area near water that slows runoff and absorbs pollutants is the best description of a buffer zone. The other descriptions describe structures that don’t provide the same natural filtration—concrete barriers don’t filter pollutants, deep trenches drain water, and chemical treatment areas process contaminants rather than buffering runoff with vegetation.