From pipes and run-off Lake pollutants may originate from either point sources or nonpoint sources in the watershed. Point sources discharge pollutants from a distinct source such as a wastewater treatment plant or industrial facility. Point sources are usually regulated by state and federal permits. Nonpoint pollutants include silt, nutrients, organic matter, and other substances originating over a relatively broad area. Water running over the land picks up these materials and transports them to the lake, either directly in runoff or through a tributary stream, drainage system, or ground water.
Water running off a lawn or driveway during a heavy rain is nonpoint source runoff.
Land uses such as agriculture, construction, and roadways contribute higher nonpoint pollutant loads than other land uses such as forests. Nonpoint pollution sources are usually controlled by implementing best management practices. Point sources were traditionally considered to be the primary dischargers of pollution to water bodies. Where pollutants come from Not all areas of the watershed are equal pollutant contributors. By identifying those critical areas that contribute excessive amounts of soil and nutrients to the lake, the most effective controls can be developed.