Lake Erie affects many human lives. The lake supplies freshwater to more than 11 million people. It is a source of drinking water, transportation, and food as well as mineral and energy resources.
One-third of the Great Lakes population lives in Lake Erie’s 30,140 square-mile watershed. Lake Erie’s watershed is the most urbanized, has the highest population density, and its land is the most intensively farmed of all the Great Lakes.
Lake Erie is directly affected by the decisions and actions of people throughout its watershed which includes parts of Michigan, Ohio, Indiana, Pennsylvania, New York, the Canadian province of Ontario, and tribal lands. Lake Erie is also impacted by the decisions of people living in the watersheds of the upper Great Lakes (Superior, Huron and Michigan) because water from these lakes and their watersheds flows into Lake Erie.
International treaties and agreements as well as local and national laws, regulations and resource management policies affect what is put into and taken out of Lake Erie. Coastal development and industrial or commercial activities throughout the watershed can lead to point and non-point source pollution. Humans have altered the biology of the lakes and the viability of species through harvesting, species introduction, habitat alteration, and nutrient and contaminant loading.
Lake Erie, its coast and watershed are impacted by land use decisions, water use decisions and natural hazards. Physical modifications (changes to beaches, shores and rivers) can exacerbate effects of erosion, storm surges and lake-level changes.
- Humans have altered the natural landscape, and ground and surface water drainage patterns of the Lake Erie watershed. Land use decisions have impacted habitats ranging from headwater forests, wetlands and oak savannahs to barrier beaches and islands, coastal wetlands such as marshes and estuaries, and nearshore aquatic areas including reefs and shoals. Land use decisions also impact water resources, changing the physical, chemical and biological composition of both Lake Erie and tributaries throughout its watershed
Eutrophication is a natural process by which freshwater lakes gradually become shallower, warmer and build up concentrations of plant nutrients as they age. Human activities in the watershed accelerate eutrophication which can lead to areas of oxygen depletion commonly referred to as “dead zones.”
- Some lakes never experience eutrophication because of a lack of warmth and light; however many do and over time, the productivity of the bodies of freshwater changes. While the rate of change is different for each lake or pond, lakes that are naturally fed rich nutrients from a stream or river or other natural source are described as "eutrophic," meaning they are nutrient-rich and therefore abundant in plant and animal life.
- Beginning in the 1960s, scientists and the public recognized that Lake Erie was undergoing accelerated/cultural eutrophication. Cultural eutrophication is the accelerated aging of a lake caused when human activity introduces increased amounts of nutrients, speeding up plant growth. Extra nutrients may come from fertilizer, detergents, or other contaminants in stormwater runoff from towns, cities, farm fields, wastewater treatment plants and golf courses. These nutrients result in excessive growth of plant life known as algal blooms. Evidence of cultural eutrophication in Lake Erie includes algal blooms covering large areas of the Western Basin during summer months; attached green algae called Cladophora covering rocky and human-made structures; decomposing algae; blue-green algae that can cause taste and odor problems in municipal water supplies; and depletion of dissolved oxygen (consumed through decomposition of algae) in some areas of the lake.
- USGS definitions for eutrophication: http://toxics.usgs.gov/definitions/eutrophication.html
- According to the Ohio Lake Erie Phosphorus Task Force II Report (2013), when water becomes anoxic, the chemical environment shifts from oxidizing to reducing and phosphorus in the bottom sediment dissolves back into the water. This occurs in the Central Basin of Lake Erie because the cold bottom layer often becomes anoxic during the summer.
- Lesson: Dead Zones
- Lesson:Activity: Sizing Up the Lake Erie Dead Zone
Coastal wetlands protect communities and the lake itself by storing flood waters, absorbing wave energy to reduce coastal erosion, and removing sediment and other pollutants from watershed streams and rivers. Lake Erie coastal wetlands have been degraded and eliminated by human activities that have comprised the ability of wetlands to perform their natural functions.
To ensure continued availability of Lake Erie assets, people must live in ways that sustain the lake. Individual and collective actions are needed to effectively conserve and manage lake resources for the benefit of all.
The Lake Erie Literacy Principles and Concepts were finalized in the spring 2011.