Agriculture has been identified as the largest contributor of nonpoint source pollution of surface and ground water systems in the United States. In a 1986 Report to Congress, the Environmental Protection Agency (EPA) noted that routine agricultural activities is responsible for over 60% of the surface water pollution problems nationwide (EPA, 1990). Accelerated erosion of productive land, nutrients (primarily, nitrogen and phosphorus) and pesticide loading from agricultural runoff, and pathogens from feedlots and urban runoff and sewage are the primary causes of surface water quality impairments.