What is Non-Point Source Pollution?

Non-Point Source Pollution ("NPS illustration")

 

 Non-point source pollution is the number one cause of water pollution in the United States (Environmental Protection Agency, n.d). Point source pollution comes from identifiable points, like stormwater discharges and industrial plants releasing pollutants into bodies of water. This type of pollution is easier to spot, identify, and therefore, regulate. However, Non-point source pollution is a less structured type of water pollution. It is usually caused by rain and snowmelt running over parking lots, yards, construction sites, and agricultural areas. The precipitation picks up chemicals, nutrients, fertilizers, oil, sediment, acid, salt, bacteria and any other pollutants, and carries them into streams, rivers, lakes, and eventually oceans. It is a very complex problem, because the issue varies greatly depending on the area, the type of land the water is running over, and the pollutants it is picking up. It is also a very large problem. Its harmful affects can reach drinking water, wildlife and biodiversity, fisheries, recreation, and the overall health of the environment.

Why is Non-Point Source Pollution a Problem?

It is necessary to understand why non-point source pollution is a problem, and what its negative effects are. Different pollutants have different consequences. One issue that is easy to visually recognize is over enrichment due to nutrient run off. Nutrients like phosphorous and nitrogen from manure and fertilizers cause growth of phytoplankton like algae and cyanobacteria. This coats the surface of a pond or lake in stagnant algae. Then, the zooplankton increase since they feed off phytoplankton. More and more plankton waste sinks in the water and feeds an increasing population of bacteria. The bacteria use up oxygen in the bottom waters which causes hypoxia-a lack of oxygen. This drives out and decreases the populations of fish that naturally reside in these bottom waters. This process is called eutrophication. It can decrease fish populations, limit recreational activity due to toxicity of the water, and effect the entire lake or pond habitat, including all animals that may depend on it as a water source.
Another common pollutant is sediment. Sediment run-off is most often caused by construct ion activities, though other types of human-caused erosion can create it also. Water polluted by sediment prevents vegetation from growing, prevents animals from seeing food, and disrupts the natural food chain by eliminating the habitat where the smallest stream organisms live (Mid-America Regional Council, n.d). It also causes problems in the treatment for drinking water, making it more costly and less effective.

Other pollutants , more likely to be found in urban run off include bacteria and viruses from pet waste and failing septic systems, salt from roads, heavy metals from roofs and vehicles, pesticides from lawns, and oil, grease and other toxic chemicals from vehicles (Environmental Protection Agency, 2010). These pollutants harm wildlife that both reside in and drink from surface waters, decrease biodiversity, and cause toxicity in our recreational and drinking waters.

Non-Point Source Pollution in Ohio          

 In Ohio, there are three main pollutants. Streams in agricultural Ohio suffer the most from excessive sediment and nutrients.  Streams in urban and suburban areas of the state are harmed by stormwater runoff of chemicals, oil, pesticides, and in construction areas, sediment. In southeastern Ohio, the main problem is the drainage of abandoned mines. This has affected around 1,300 streams in the area. (Division of Surface Water, n.d.). 

 In central Ohio, the Scioto and Olentangy Rivers play important roles in Columbus and the surrounding counties. They provide drinking water for tens of thousands of people, recreation, scenery, and habitat for wildlife, including many endangered and threatened species (Friends of the Lower Olentangy Watershed, n.d). The rivers are greatly impaired by non-point source pollution. Agricultural run off of nutrients in the northern, agricultural areas, the various pollutants of urban run-off in Columbus, and sedimentation are all issues that need addressed. 

Convergence of Scioto and Olentangy Rivers with Columbus Skyline (Gulvas, 2003)

Other important surface waters are affected also. Grand Lake St. Marys is a startling example of the effects of excessive nutrients from agricultural run off. The nutrients, primarily phosphorous and nitrogen, are picked up by water running over the agricultural fields that have been applied with fertilizers and/or manure. The large concentrations of nutrients are helpful to soil, but have harmful effects on surface water and the biodiversity that resides in them. The eutrophication in the Lake is so extreme that there is a constant layer of algae and cyanobacteria blanketing the water. People are advised not to touch the water or use it for any recreational purposes because of the toxicity of the large quantities of cyanobacteria. Grand Lake St. Marys is now a hindrance and a problem, instead of a resource that provides valuable ecosystem services, and there are many more like it.

Lake St. Mary's Signage (Russell, 2010)

Solutions for Non-Point Source Pollution

Though it seems too broad to be fixed, there are solutions to non-point source pollution. Some of the best answers are those that help water to soak into the ground and/or be filtered before it reaches surface waters. Simple, small solutions like rain gardens—special gardens with certain plants and structure that allow water to filter and soak into the ground—and rain barrels—barrels that catch water from rain spouts to be used to water gardens or lawns—can be utilized by homeowners and business owners (EPA, n.d.). Planting trees and shrubs to prevent erosion and soak up water, using gravel or stones instead of pavement and cement, and leaving 10-20 feet of un-mowed grass and weeds around streams (riparian buffers), are all simple methods of preventing non-point source pollution that are slowly growing in use and popularity (MARC).
On a larger scale, the Ohio EPA and the USDA have created programs and action plans to combat the problems that are assaulting the Olentangy and Scioto Rivers and their watersheds. The Ohio EPA recently revised their Ohio Nonpoint Source Pollution Management Plan, which lays out specific goals and enacts a variety of specific solutions, studies to be done, regulations to be put into place, etc. This includes the restoration of wetlands, the removal of low-head dams, agricultural regulation, stream restoration, and many other management practices that will improve the water quality of Ohio (DSW). Some of the USDA’s incentive programs are playing a crucial role also. The Scioto River Watershed Conservation Reserve Enhancement Program is a program focusing on the Upper Scioto Watershed. It is a cooperation between the USDA and the Ohio Division of Natural Resources. “It is a farmer/landowner-implemented agricultural environmental stewardship program.  The goal is to create filter strips, riparian buffers, wildlife habitat, wetland, and tree plantings to reduce sediment and nutrient runoff into the river and it tributaries.  As a result it will improve biodiversity in the entire watershed”(Olentangy Watershed Alliance, n.d.).

Non-Point source pollution is a complex problem. It comes from a multitude of sources and affects water quality in a multitude of ways. It disrupts the ecosystem, decreases biodiversity, harms wildlife, and hurts economic and recreational interests. Fortunately, the Ohio EPA, the USDA, and private individuals are trying to combat it with a variety of restoration techniques and regulation.

References

Division of Surface Water. (n.d.). Nonpoint source program.. Retrieved February 24, 2012, from  http://epa.ohio.gov/dsw/nps/index.aspx

Environmental Protection Agency. (2010). Urban runoff. Retrieved April 15, 2012, from          http://www.epa.gov/owow_keep/NPS/urban.html

Environmental Protection Agency. (n.d.). What is nonpoint source pollution? Retrieved April 15, 2012 from http://water.epa.gov/polwaste/nps/whatis.cfm

Friends of the Lower Olentangy Watershed.(n.d). The Olentangy watershed. [Brochure]. Columbus, OH: Author

Gulvas, S. (Photographer). (2003). [Untitled photograph of confluence of Scioto and Olentangy   Rivers], Retrieved April 23, 2012 from http://www.roadfan.com/colsky.html

Mid-America Regional Council.(n.d). What is sediment pollution? [Brochure]. Kansas City, MO: Author

Olentangy Watershed Alliance. (n.d). Conservation opportunities. Retrieved April 10, 2012 from  http://www.olentangyriver.org/web/index.php?option=com_content&task=blogcategory            &id=28&Itemid=40

Russell, C. (Photographer). (2010). [Untitled photograph of sign at Grand Lake St. Marys],          Retrieved April 12, 2012, from http://www.dispatch.com/content/stories/local/2010/06/29/dont-touch-the-water.html

 [NPS illustration] Retrieved April 20, 2012 from http://www.mfe.govt.nz/environmental-reporting/freshwater/river/nutrients/sources.html