NPS pollution occurs when rainwater or snow melt carries sediment, organic materials, nutrients, or toxins into rivers, lakes, and streams. During large storms the runoff to surface water and the rate of infiltration to groundwater increases, and so does the rate of NPS pollutant movement. Almost any land use can lead to NPS pollution. The more intensive the land use, the greater the chance of pollution. NPS comes from a variety of sources in both urban and rural areas.
NPS pollution is now the number one cause of water quality problems in Ohio. NPS affects drinking water supplies, wildlife habitat, recreational opportunities such as boating, swimming, fishing, and much more. It is the major challenge in our battle for cleaner water. Based on data from the OEPA, NPS pollution affects over 13,700 miles of Ohio’s 29,113 perennial stream miles. Twenty-nine percent of these perennial streams are classified as impaired as a result of nonpoint source pollution.
Examples of NPS pollution include:
MS4 stands for Municipal Separate Storm Sewer Systems
Since 1972, permits for wastewater have been required through the Clean Water Act.
In 1990, the USEPA began to regulate stormwater from Municipal Separate Storm Sewer Systems, Industrial Storm Water, and Construction Sites disturbing 5 acres or greater. (Phase I)
In 1999 Phase II added small municipalities (in urbanized areas as defined by census data) and construction activities disturbing 1 acre or greater to the list of permitted entities.
Under Phase II, permitted entities must develop a plan aimed at reducing the discharge of pollutants and protecting or improving existing water quality by implementing six minimum control measures.
The six minimum measures are: