WHAT IS SOIL EROSION?

Erosion is a natural process by which the surface of the land is worn away by water, wind or chemical action.

Accelerated erosion is the removal of the surface of the land through the combined action of human activities and natural processes at a rate greater than would occur from natural processes alone.

IS SEDIMENT REALLY A POLLUTANT?

A certain amount of erosion and sediment occurs naturally. Because it is a natural process, nature is able to assimilate naturally occurring sediments without permanent adverse effects. Adverse effects most often result from accelerated erosion due to earth disturbance activities such as surface mining, agricultural plowing and tilling, construction, and timber harvesting operations.

Why is sediment pollution harmful?

• Fish have gills which extract oxygen from the water. These gills can become clogged when the water transports excessive amounts of sediment.

• Sediment can cover fish eggs and the gravel nests they rest in.

• Sediment can destroy the food supply for many species of fish by covering aquatic insect habitat on the stream bottom.

• Sediment clouds the water and deprives plants of light needed for photosynthesis. This is thought to be the primary cause of the widespread die-off of aquatic vegetation in the Chesapeake Bay.

• Sediment may carry other pollutants such as heavy metals, pesticides and excess nutrients that are spread by water action and cause problems not only at the source, but also downstream.

• Sediment loads in our waterways often result in eroded and unstable streambanks.

• Sediment increases public drinking water treatment costs or may render unfiltered drinking water supplies harmful for consumption.

• Excess sediment deposits in streams and rivers may necessitate the dredging of a reservoir or other body of water.