Nonpoint source pollution (NPS) occurs when rainfall, snowmelt, or irrigation runs over land or through the ground, picks up pollutants, and deposits them into rivers, lakes, and coastal waters or introduces them into ground water. NPS pollution remains the Nation’s largest source of water quality problems. It’s the main reason that many of our surveyed rivers, lakes, and estuaries are not clean enough to meet basic uses such as fishing or swimming.
NPS pollution is essentially all sources of pollutants, which do not discharge through either a treatment plant effluent, outfall pipe or sewage collection system. Major sources of nonpoint pollution in New York include agriculture, hydrologic and habitat modification, failing on-site septic systems, and urban/stormwater runoff. In New York, the “urban/stormwater runoff” source includes construction, urban runoff, storm sewers, highway maintenance/runoff (road salt), and roadbank erosion, while “hydrologic and habitat modification” refers to physical alterations in the landscape, shore, or waterbody, including streambank erosion, that change aquatic ecosystems, cause loss of aquatic life, or alter the flow of the watercourse (e.g., channelization, dewatering, damming, or dredging). In addition to these major sources, NYS Department of Environmental Conservation reports to the US Environmental Protection Agency on atmospheric deposition, accidental spills, contaminated sediments, resource extraction, silviculture, land disposal and landfills.
The challenge in successfully reducing NPS pollution and restoring good water quality lies in applying measures to reduce or prevent the pollutants generated by NPS pollution. Strategies can be developed and implemented to reduce and prevent NPS impacts and restore the health of watersheds (add link to WQ Strategy).
What Pollutants contribute
to Nonpoint Source Pollution?
Pollutants (such as, dissolved oxygen/oxygen demand, priority organics, metals,
pathogens, nutrients, silt/sediment, aesthetics, thermal changes, and pesticides)
cause point and nonpoint source impacts to water uses (for drinking, recreation,
trout and trout propagation, fishing).
Possible pollutants and sources of pollution in waterbodies are assessed by the NYS Department of Environmental Conservation using biological sampling, water chemistry data collection, other available monitoring data, and best professional judgment based on surrounding land use. With this information, the Water Quality Committee can prioritize watersheds/sub watersheds for protection and restoration activities.
Activities that are
associated with development, such as excavation, paving, and tree removal, contribute
to erosion and sedimentation and introduce large amounts of polluted runoff
into our waterways. Stormwater runoff is a leading source of NPS pollutants
in urban areas. The table below identifies leading pollutants and sources across
the country.
http://www.epa.gov/305b/98report/“Water
Quality Conditions in the United States: A Profile from the 1998 National Water
Quality Inventory Report to Congress”. Source: 98summary.pdf