Urban and agricultural runoff (known legally as non-point pollution) is the most significant source of pollution in the Great Lakes. As the United States and Canada are considering revisions to the Great Lakes Water Quality Agreement, addressing runoff pollution should be a top priority. Carrol Hand, a law student at Tulane, worked with the Great Lakes Environmental Law Center to develop a white paper on non-point pollution and the Great Lakes Water Quality Agreement. Carrol brings significant experience and expertise to this project, having worked with NOAA’s Great Lakes Environmental Research Lab, the U.S. EPA, and the Great Lakes Institute for Environmental Research at the University of Windsor (where she also earned a graduate degree). Carrol’s white paper is available online, and she provided the following guest post as an introduction to the topic:
Changes in the urban and agricultural landscape of the Great Lakes have resulted in an increased threat to the water quality of the lakes. Pollution entering the Great Lakes comes from both ‘point sources’ and ‘non-point sources.’ Point sources are more easily identified and managed, since they are limited to a single location like an oil refinery, industrial factory, or municipal wastewater treatment plant. In contrast, non-point source pollution (also known as runoff pollution) comes from a variety of diffuse sources which are difficult to identify. Consequently, the overall success at controlling non-point source pollution has been low, so much so that the EPA considers it “the most important remaining source of water pollution” in the Great Lakes Basin.
In the Great Lakes region, non-point sources are responsible for 76% of the pollution in the water. One of the primary effects of that pollution is eutrophication, due to excessive amounts of phosphorus and nitrogen. Eutrophication results in the growth of nuisance algae (such as cyanobacteria), which can lead to fish kills, foul odors, and undrinkable water.
Traditionally agriculture has been recognized as a primary cause of non-point pollution, particularly since urban areas only account for around 5% of the land in the continental United States. More recently it has been acknowledged that urban sources can play a much larger part. In the lower Great Lakes (dominated by the Corn Belt) non-point source pollution does come primarily from agricultural sources, but in the upper Great Lakes non-point pollution comes primarily from forestry and urban sources. Agricultural non-point pollution comes primarily from fertilizer and manure, while in contrast much of the urban non-point source pollution comes from nutrients, sediment and bacteria that find their way into the Great Lakes through stormwater runoff from streets, parking lots, lawns, driveways, and roofs. In addition to pollutants picked up from the land, pollutants (nutrients in particular) that are deposited from the atmosphere also find their way into the waters of the Great Lakes. Atmospheric deposition is one of the largest non-point sources of nitrogen deposited in the lakes, specifically coming from gases released from agriculture and the burning of fossil fuels.
In response to concerns about Great Lakes water quality, the United States and Canada entered into the Great Lakes Water Quality Agreement in 1972 with a commitment “to restore and maintain the chemical, physical and biological integrity of the Great Lakes Basin ecosystem.” However, the Great Lakes Water Quality Agreement has failed to significantly limit non-point pollution in the Great Lakes due to a lack of accountability and enforcement mechanisms. To fulfill its promise, the Great Lakes Water Quality Agreement must be amended to substantively address non-point pollution and provide the legal and policy tools to make the controls effective.
The Great Lakes are coming close to a turning point. Increased urbanization throughout the basin has resulted in a substantial growth of surface area that is impermeable to rainwater and runoff. Consequently, nutrients, pathogens and sediment, all of which are being produced in increasingly large volumes, are transported into the lakes in greater amounts. Agriculturally, global market forces are moving farming practices away from small family farms towards large, intensive operations such as confined animal feeding operations. Better controls need to be put into place to handle non-point source pollution, or the condition of our Great Lakes may take a serious turn for the worse.