Understanding Non-Point Water Pollution: Causes And Solutions

Nonpoint source (NPS) pollution is any source of pollution that does not meet the point source definition under the Clean Water Act. Nonpoint sources are runoff from rain or snow melt carrying natural and anthropogenic pollutants to waters, such as lakes, rivers, wetlands, coastal waters and groundwater. NPS areas of focus are driven by particular land uses.

Runoff from rain and snowmelt carries pollutants into waterways

Nonpoint source (NPS) pollution is any source of pollution that does not meet the point source definition under the Clean Water Act. Nonpoint sources are runoff from rain or snow melt carrying natural and anthropogenic pollutants to waters, such as lakes, rivers, wetlands, coastal waters and groundwater. NPS areas of focus are driven by particular land uses.

Runoff is a major cause of nonpoint-source pollution. For example, picture a city street during a thunderstorm. As rainwater flows over asphalt, it washes away drops of oil that leaked from car engines, particles of tire rubber, dog waste, and trash. The runoff goes into a storm sewer and ends up in a nearby river.

Activities on working farms and ranches can affect water quality, both locally and across multi-state watersheds. Forestry activities such as removal of streamside vegetation, road construction and use, timber harvesting, and mechanical preparation for the planting of trees can impact water quality. Hydromodification activities include channelization and channel modification, dams, and streambank and shoreline erosion.

Municipal wastewater treatment plants are another common source of point-source pollution. Effluent from a treatment plant can introduce nutrients and harmful microbes into waterways. Nutrients can cause a rampant growth of algae in water.

Nonpoint-source pollution is the opposite of point-source pollution, with pollutants released in a wide area. The name “nonpoint source pollution" is derived from the concept that there is no single point from which the pollution comes; it comes from everyone and everywhere. Nonpoint source (NPS) pollution is the nation’s and the state’s number one threat to water quality.

Nonpoint source pollution is the nation’s and the state’s number one threat to water quality

Nonpoint source (NPS) pollution is the nation's and the state's number one threat to water quality. It occurs when runoff from rain and snowmelt carries pollutants into waterways such as rivers, streams, lakes, wetlands, and even groundwater. The name “nonpoint source pollution” is derived from the concept that there is no single point from which the pollution comes; it comes from everyone and everywhere.

Nonpoint source pollution comes from oil, pet waste, pesticide, herbicide, fertilizer, road salt, bacteria, sediment, and any other contaminant that ends up on the ground naturally or from human activity. Rainwater and snowmelt picks up these contaminants as it washes over yards, sidewalks, driveways, parking lots, and fields and deposits them into Indiana’s lakes and streams as nonpoint source pollution.

Activities on working farms and ranches can affect water quality, both locally and across multi-state watersheds. Forestry activities such as removal of streamside vegetation, road construction and use, timber harvesting, and mechanical preparation for the planting of trees can impact water quality. Hydromodification activities include channelization and channel modification, dams, and streambank and shoreline erosion.

Under Section 319 of the Clean Water Act, states, territories and Tribes must identify categories of sources of NPS pollution as part of an assessment report required for obtaining a Section 319(h) grant. The links below provide information on these source categories, and on practices to reduce the impacts of NPS pollution in each of those categories.

Activities on working farms and ranches can affect water quality

Nonpoint source (NPS) pollution is any source of pollution that does not meet the point source definition under the Clean Water Act. Nonpoint sources are runoff from rain or snow melt carrying natural and anthropogenic pollutants to waters, such as lakes, rivers, wetlands, coastal waters and groundwater. NPS areas of focus are driven by particular land uses.

Livestock facilities are a major source of NPS pollution in Illinois. Runoff from farm fields can carry pet waste, pesticide, herbicide, fertilizer, road salt, bacteria, sediment, and any other contaminant that ends up on the ground naturally or from human activity. Rainwater and snowmelt picks up these contaminants as it washes over yards, sidewalks, driveways, parking lots, and fields and deposits them into Indiana’s lakes and streams as nonpoint source pollution.

Construction sites are another major source of NPS pollution. Runoff from construction sites can carry pet waste, pesticide, herbicide, fertilizer, road salt, bacteria, sediment, and any other contaminant that ends up on the ground naturally or from human activity. Rainwater and snowmelt picks up these contaminants as it washes over yards, sidewalks, driveways, parking lots, and fields and deposits them into Indiana’s lakes and streams as nonpoint source pollution.

Lawn and garden activities are also a major source of NPS pollution. Runoff from lawn and garden activities can carry pet waste, pesticide, herbicide, fertilizer, road salt, bacteria, sediment, and any other contaminant that ends up on the ground naturally or from human activity. Rainwater and snowmelt picks up these contaminants as it washes over yards, sidewalks, driveways, parking lots, and fields and deposits them into Indiana’s lakes and streams as nonpoint source pollution.

Forestry activities can impact water quality

Nonpoint source (NPS) pollution is any source of pollution that does not meet the point source definition under the Clean Water Act. Nonpoint sources are runoff from rain or snow melt carrying natural and anthropogenic pollutants to waters, such as lakes, rivers, wetlands, coastal waters and groundwater. NPS areas of focus are driven by particular land uses.

Forestry activities such as removal of streamside vegetation, road construction and use, timber harvesting, and mechanical preparation for the planting of trees can impact water quality. Rainwater and snowmelt picks up contaminants as it washes over yards, sidewalks, driveways, parking lots, and fields and deposits them into Indiana’s lakes and streams as nonpoint source pollution.

The major sources of NPS pollution in Illinois include runoff from farm fields, livestock facilities, construction sites, lawns and gardens, city streets and parking lots, surface coal mines, and forestry. The Clean Water Act has been so successful at reducing pollution discharges from industries and municipalities (point sources) that the single largest source of water contamination today comes from nonpoint source pollution.

Nonpoint-source pollution is the opposite of point-source pollution, with pollutants released in a wide area. As an example, picture a city street during a thunderstorm. As rainwater flows over asphalt, it washes away drops of oil that leaked from car engines, particles of tire rubber, dog waste, and trash. The runoff goes into a storm sewer and ends up in a nearby river. Runoff is a major cause of nonpoint-source pollution.

Hydromodification activities include channelization and channel modification, dams, and streambank and shoreline erosion

Nonpoint source pollution occurs when runoff from rain and snowmelt carries pollutants into waterways such as rivers, streams, lakes, wetlands, and even groundwater. The name “nonpoint source pollution" is derived from the concept that there is no single point from which the pollution comes; it comes from everyone and everywhere. Nonpoint source (NPS) pollution is the nation’s and the state’s number one threat to water quality.

These activities can have significant impacts on water quality and can lead to the release of pollutants into waterways. For example, channelization and channel modification can increase the speed and volume of water flow, which can lead to increased erosion and sedimentation in the waterway. Dams can also contribute to water pollution by creating stagnant water pools that can become breeding grounds for harmful algae blooms and other aquatic organisms. Streambank and shoreline erosion can release pollutants such as sediment, nutrients, and bacteria into the waterway, which can reduce water quality and harm aquatic ecosystems.

To reduce the impacts of NPS pollution, it is important to identify the sources of pollution and implement measures to control and mitigate them. This can include implementing best management practices in agriculture, urban areas, and forestry, as well as restoring and protecting natural habitats such as streamside vegetation and wetlands.

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