These methods, called best management practices, are practical and manageable on a voluntary basis. Agricultural Runoff Agricultural runoff is excess water from rainfall and other precipitation that runs off the land. When uncontrolled, agricultural runoff removes topsoil, nutrients, pesticides, and organic materials and carries them to water bodies where they become pollutants. In Nebraska, the estimated average erosion rate is more than 140 million tons annually. By volume, sediment resulting from erosion is the nation's largest single water pollutant.
Erosion is the detachment of soil particles from clods and the soil surface.
Most of this occurs during rain storms which can detach or loosen up to 100 tons of soil per acre in a severe storm. The detached soil can be transported by agricultural runoff which dislodges additional soil particles as it flows across unprotected soil surfaces. Heavier soil particles may settle out in bottomlands and on footslopes before reaching a body of water. This eroded soil can cover and destroy young plants and cause future drainage problems. Sediment fills streams, rivers, reservoirs, lakes and roadside ditches, reducing their useful life.