Sediments

You’ve seen a muddy river after a rainstorm? That's a product of sediment runoff. Sediments are soil particles carried by stormwater runoff into streams, lakes, rivers and bays. It’s caused mainly by erosion resulting from bare land, poor farming practices on cropland and pastureland, and construction and development of the land. By volume, sediment is the greatest pollutant of all.

Sedimentation is a harmful form of NPS pollution because it cuts down on the light needed by underwater grasses. Sedimentation also clogs waterways, drainage systems, buries aquatic habitat, and smothers fish and shellfish spawning grounds. Compounding the problem, sedimentation from eroded farmland can contain pesticides and fertilizers. If you read about nutrients, you will learn about decreased light and oxygen from nutrients, resulting in fish and grasses dying off; sedimentation has the same effect.