Polluted Runoff: Nonpoint Source Pollution

Nonpoint source: Agriculture

Strip till cropping in Wisconsin 319The United States has more than 330 million acres of agricultural land that produce an abundant supply of food and other products. American agriculture is noted worldwide for its high productivity, quality and efficiency in delivering goods to consumers. When improperly managed, however, activities from working farms and ranches can impact local and far-field water quality.

The National Water Quality Assessment shows that agricultural nonpoint source (NPS) pollution is the leading source of water quality impacts on surveyed rivers and streams, the third largest source for lakes, the second largest source of impairments to wetlands, and a major contributor to contamination of surveyed estuaries and ground water.

Agricultural activities that cause NPS pollution most generally occur in the absence of a conservation plan. Impacts can be generated from activities such as poorly located or managed animal feeding operations and manure, overgrazing, plowing too often or at the wrong time and improper application fertilizer.