What is nonpoint source pollution and what management practices reduce it?

• A. Point source discharge from a pipe; reduced by improved filtration only.
• B. Diffuse pollution from land runoff; reduced by BMPs such as cover crops, contour farming, buffer strips, wetlands, and stormwater management.
• C. Atmospheric deposition only; reduced by air permits.
• D. Groundwater extraction; reduced by pumping more.

Answer: (B)

Nonpoint source pollution comes from many diffuse sources and is carried to water bodies by rainfall or snowmelt runoff, rather than from a single identifiable pipe or outlet. It includes sediments, nutrients, pesticides, and other pollutants picked up across large land areas like agricultural fields, urban surfaces, and disturbed soils. The way to reduce it best is to implement best management practices that lessen runoff and improve filtration. Cover crops protect soil during off-seasons, reducing erosion and nutrient loss. Contour farming slows water flow across slopes and promotes infiltration. Buffer strips of vegetation along streams trap sediments and absorb nutrients before they reach the water. Wetlands provide natural filtration and storage, and stormwater management practices control the volume and timing of runoff, lowering pollutant loads entering waterways. These approaches address the runoff pathway that characterizes nonpoint pollution rather than a single discharge point or a different pollution route.