Great Lakes Quickfacts
Have you ever wondered what makes the Great Lakes great? Here are some facts about the Great Lakes that highlight their unique history, physical features, population and resource contributions.
All facts are in Canadian dollars unless indicated otherwise.
History and Physical Features
- Many of the lakes on the Canadian Shield, including the Great Lakes, were created by glacial erosion.
- The combined shoreline of the Great Lakes is equal to about 42% of the earth's circumference.
- The Great Lakes basin covers an area greater than 765,000 square kilometres.
- Canada's longest inland waterway stretches 3,700 kilometres from the Gulf of St. Lawrence to Lake Superior.
- The Great Lakes are the largest system of fresh surface water on earth, containing roughly 21% of the world's fresh surface water.
- Only 1% of the waters of the Great Lakes are renewed each year by snow melt and rain.
- The most severe storm flooding event in the Great Lakes basin occurred on October 14 and 15 1954, when Hurricane Hazel brought 214 millimetres of rain to the Toronto area over 48 hours.
- Extreme weather events, including storm related flooding, have become the most costly type of natural disaster in Canada in terms of property damage.
- The first Canadian Heritage River was the French River in Ontario, designated in 1986.
- In Canada, the Great Lakes basin covers an area greater than 321,000 square kilometres.
- Lake Superior is the largest of the Great Lakes, holding about 12,100 cubic kilometers of water, the equivalent to all the water in the other Great Lakes, plus three more Lake Erie’s.
- Ontario’s portion of the Great Lakes forms the longest freshwater coastline in the world, measuring more than 11,000 kilometers.
- In many areas of the Great Lakes basin, 50% to 90% of coastal wetlands have been lost due to development, pollution, invasive species, water level fluctuations and climate change impacts.
- By 2001, approximately 74% of the original coastal wetlands between the Niagara River and Toronto have been lost to development.
Population and Resource Contributions
- Almost 60% of the world’s fresh water falls within a transboundary basin like the Great Lakes, where at least one of the tributaries crosses a political boundary.
- 43% of Canada’s boundary with the United States is composed of water.
- The Great Lakes basin is home to 96% of Ontario’s population and, as of 2012, it contributes 37% of Canada's economic activity, measured as gross domestic product (GDP).
- As of 2006, the Great Lakes support a population of 39 million people, including 11 million Canadians and seven of Canada’s largest 20 cities.
- The Great Lakes provide drinking water to 10 million Canadians.
- 84% of all farm land in Ontario is found in the Great Lakes basin, and in 2011, Ontario alone represented 32% of Canada’s agriculture and food processing GDP.
- Each year, the Great Lakes region contributes $180 billion to Canada-U.S. trade.
- 11% of all water withdrawn from the Great Lakes basin is for industrial uses.
- Each year, the Great Lakes commercial fishing industry contributes $350 million to Ontario’s GDP.
- Canadians spend $443 million a year on recreational fishing in the Great Lakes, including expenses for transportation, food, lodging and supplies.
- By 2002, the wetland area in southern Ontario was estimated to have been reduced by 72%, representing a loss of over 1.4 million hectares.
- Each year, Lake Erie’s commercial fishing industry accounts for 78% of the total value of Ontario’s commercial fishery.
- As of 2005, of the Canadian residents who fish recreationally on the Great Lakes, 90% fish on lakes Huron, Ontario, and Erie.
- Of the Canadian residents who fish recreationally on the Great Lakes, 44% fish on Lake Huron.
- The number of residents fishing in Ontario in 2005 dropped by more than half compared to ten years before.
- Groundwater in the Great Lakes basin provides 82% of the rural population with drinking water.
- In 2012, the total amount of water withdrawn from the Great Lakes-St. Lawrence River Basin was 167.8 billion liters per day, the equivalent of 0.68% of the total volume of the lakes.
- The total amount of water withdrawn from the Great Lakes-St. Lawrence River Basin that is not returned to the basin is 12,672 million litres per day.
- The lake watershed with the greatest amount of water withdrawn is Lake Michigan, followed by lakes Erie and Ontario.
The Economy of the Great Lakes Basin
- In 2012, the Great Lakes region had a combined GDP of $5.2 trillion among the two provinces and eight states.
- The Great Lakes and St. Lawrence River region supports 56 million jobs shared by Canada and the United States.
- The Great Lakes-St. Lawrence Seaway System alone directly employs more than 92,000 people in Canada and the United States.
- In 2010, Ontario had over 73 million tourist visits in the Great Lakes Region with estimated spending of $12.3 billion.
- In 2011, cargo shipments on the Great Lakes-St. Lawrence Seaway System generated $34.6 billion of economic activity in the Canada and the United States.
- More than 160 million metric tons of cargo is moved on the Great Lakes-St. Lawrence Seaway System annually.
- The three commodities that are most frequently shipped from the Great Lakes-St. Lawrence Seaway system are iron ore (38% of shipments), coal (19%) and stone and aggregate (13%).
Aquatic Invasive Species
- More than 180 invasive aquatic species are present in the Great Lakes Basin.
- Since the zebra mussel was first introduced in Lake St. Clair in 1988, it has spread to all the Great Lakes and the St. Lawrence River.
- Ontario has the highest risk of species invasions compared to other Canadian provinces and territories as approximately 64% of the overseas containers that arrive in Canada are opened in the Ontario portion of the Great Lakes basin.
- Since 2006, no new invasive species have been recorded as entering the Great Lakes from ships’ ballast water.
- The overall economic impact of aquatic invasive species on the Great Lakes region is estimated at over $100 million annually.
- Cumulative costs associated with damages from zebra mussels in the Great Lakes range from $3 billion to $7.5 billion.
- Invasive species in the Great Lakes are estimated to cost $5.7 billion (USD) per year in economic losses, with commercial and sport fishing accounting for almost 80% of the loss.
- Tourism in the Great Lakes region is impacted by the presence of zebra mussels, resulting in an estimated loss of US$500,000 in the sector in 2005.
Climate Change and the Great Lakes
- Since the early 1970s, the amount of ice forming on the Great Lakes each season has declined by at least 6% on each lake.
- The overall ice coverage of the Great Lakes has been reduced by 63% compared to 1973.
- Since the 1980s, the average shipping season of the St. Lawrence Seaway has increased by 10 days as a result of declining lake ice cover.
- Lake evaporation is increasing and will likely continue to increase in the future as a result of reduced ice cover, increasing surface water temperatures and wind speeds.
- As a result of low lake levels in 2000, Fisheries and Oceans Canada allocated $15 million in emergency dredging funds for the Great lakes ports and marinas.
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