Watershed Management - Sources of Pollution

Sources of Pollution

In an agricultural landscape, common contributors to water pollution are nutrients and sediment which typically enter stream systems after rainfall washes them off poorly managed agricultural fields, called surface runoff, or flushes them out of the soil through leaching. These types of pollutants are considered nonpoint source pollution because the exact point where the pollutant originated cannot be identified. Such pollutants remain a major issue for water ways because the difficulty to control their sources hinders any attempt to limit the pollution. Point source pollution originates a specific point of contamination such as if a manure containment structure fails and its contents enter the drainage system or when a factory discharges its waste directly into a body of water using a pipe.

In urban landscapes, issues of soil loss through erosion, from construction sites for example, and nutrient enrichment from lawn fertilizers exist. Point source pollution, such as effluent from waste water treatment plants and other industries play a much larger role in this setting. Also, the greatly increased area of impervious surfaces, such as concrete, combined with modern storm drainage systems, allows for water and the contaminants that it can carry with it to exit the urban landscape quickly and end up in the nearest stream.