Great Lakes facts for kids

Quick facts for kids Great Lakes of North America
Great Lakes
The Great Lakes seen from NASA's Aqua satellite in August 2010. From left to right: Lake Superior, Michigan, Huron, Erie, Ontario
Bathymetry map of the Great Lakes
Location	Eastern North America
Coordinates	45°N 84°W / 45°N 84°W / 45; -84
Type	group of interconnected freshwater lakes
Part of	Great Lakes Basin
Primary inflows	Past: precipitation and meltwater Now: rivers, precipitation, and groundwater springs
Primary outflows	Evaporation, St. Lawrence River to the Atlantic Ocean
Basin countries	Canada, United States
Surface area	94,250 square miles (244,106 km2)
Average depth	60–480 ft (18–146 m) depending on the lakes
Max. depth	210–1,300 ft (64–396 m) depending on the lakes
Water volume	5,439 cubic miles (22,671 km3) (lowest)
Frozen	around January to March

The Great Lakes

View from space of the Great Lakes

The Great Lakes are five large lakes in east-central North America. They hold 21% of the world's surface fresh water.

The lakes are:

• Lake Superior
• Lake Michigan
• Lake Huron
• Lake Erie
• Lake Ontario

How were the Great Lakes formed?

A long, long time ago, during the Ice Age, giant sheets of ice called glaciers covered much of North America. These glaciers were like giant bulldozers, scraping and carving the land as they moved. About 10,000 years ago, as the climate warmed, the glaciers began to melt. The melting ice filled the deep basins that the glaciers had carved, creating the Great Lakes we know today.

Geography

Great Lakes: system profile

Four of the Great Lakes are on the border between Canada and the United States of America. The other, Lake Michigan, is completely inside the United States.

All together, by volume, they are the largest group of fresh water lakes in the world. No one of the Lakes is larger than Lake Baikal (Russia) or Lake Tanganyika (East Africa).

The cities of Chicago, Illinois (9.8 million people, on Lake Michigan), Toronto, Ontario (5.5 million, on Lake Ontario); Detroit, Michigan (5.3 million, on the Detroit river); Montreal, Quebec (3.9 million, on the St. Lawrence River), Cleveland, Ohio (2.9 million, on Lake Erie), Buffalo, and Ottawa (1.2 million, Ontario, on the Ottawa River) are on the shores of the Great Lakes or their rivers.

Though the five lakes have separate basins, they form a single, connected body of freshwater. The lakes connect the east-central interior of North America to the Atlantic Ocean. Lakes Michigan, Huron and Erie are approximately equally high and ships can easily pass from one to the next. Water flows from Lake Superior and Lake Michigan into Lake Huron; then through the Detroit River into Lake Erie; then through Niagara Falls into Lake Ontario; and then through the Saint Lawrence River to the Atlantic Ocean. Water also drains from the Chicago River on the south.

Many rivers flow through a large watershed into the lakes. The lakes have about 35,000 islands. The Great Lakes region includes the five lakes and many thousands of smaller lakes, often called inland lakes.

The unusual shape of the Great Lakes has created the possibility of large waves called seiche. If a storm causes a fast, strong increase in air pressure on one side of a lake, the water level on that side of the lake will drop and suddenly push up the water level on the opposite side of the lake. A 10 foot tall wave in Chicago caused several deaths in 1954.

Ecological threats

The Great Lakes are home to a variety of species of fish and other organisms. In recent years, overfishing caused a decline in lake trout. The drop in lake trout increased the alewife population. In response, the government introduced salmon as a predator to decrease the alewife population. This program was so successful that the salmon population rose rapidly, and the states surrounding Lake Michigan promoted 'salmon snagging'. This has been made illegal in all of the Great Lakes states except for a limited season in Illinois. Lake Michigan is now being stocked with several species of fish. However, several invader species such as lampreys, round goby, and zebra mussels threaten the native fish populations.

Invasive species

Accidentally introduced species are a big problem. Since the 19th century about 160 species have invaded the Great Lakes ecosystem, causing severe economic and ecological impacts. According to the Inland Seas Education Association, they deprive fish of food, cause blooms of toxic algae, and foul boats, spawning areas and drinking water intakes. On average a new invasive species enters the Great Lakes every eight months.

Two important infestations in the Great Lakes are the zebra mussel, first discovered in 1988, and the quagga mussel in 1989. These molluscs are efficient filter feeders. They compete with native mussels, and also reduce available food and spawning grounds for fish.

Also, the mussels hurt utility and manufacturing industries by clogging or blocking pipes. The U.S. Fish and Wildlife Service estimates that the economic impact of the zebra mussel will be about $5 billion over the next decade. Because the quagga mussel is good at filtering plankton from the lake water, sunlight reaches deeper into the lake. This increases the growth of algae.

Pollution

Chemicals from industrial plants run off the land into rivers and arrive in the lakes. Some of these chemicals are highly toxic, such as mercury. Contaminated water from sewer overflows also reaches the lakes, and beaches get closed because of the threat of pathogenic bacteria.

Why are the Great Lakes important?

The Great Lakes are super important for many reasons:

• Drinking water: They provide drinking water for millions of people in both the United States and Canada.
• Transportation: The Great Lakes are like giant highways for ships. They allow ships to transport goods like iron ore, grain, and coal to different cities and countries.
• Fishing: The Great Lakes are home to many different kinds of fish, like trout, salmon, and whitefish. People fish in the Great Lakes for fun and for food.
• Recreation: The Great Lakes are a great place to have fun! People go swimming, boating, kayaking, and sailing on the lakes. There are also beautiful beaches and parks along the shores of the Great Lakes.
• Ecosystem: The Great Lakes are home to a wide variety of plants and animals. They provide a habitat for fish, birds, mammals, and insects.

Fun facts about the Great Lakes

• Lake Superior is the largest freshwater lake in the world by surface area. That means it covers the most space!
• The water in Lake Superior is so clear that you can see objects up to 27 feet (8 meters) deep!
• Lake Michigan is the only Great Lake that is entirely within the United States.
• Lake Huron has the longest shoreline of all the Great Lakes, including about 30,000 islands!
• Lake Erie is the shallowest of the Great Lakes, with an average depth of only 62 feet (19 meters).
• Lake Ontario is the smallest of the Great Lakes by surface area. It's connected to the Atlantic Ocean by the St. Lawrence Seaway, which allows ships to travel from the Great Lakes to the ocean.

Images for kids

• 

  Satellite image of the Great Lakes taken by the Terra satellite on June 16, 2021

• 

  Terra MODIS image of the Great Lakes, January 27, 2005, showing ice beginning to build up around the shores of each of the lakes, with snow on the ground; Green Bay, the North Channel, Saginaw Bay, and Lake St. Clair show complete ice coverage.

• 

  Location in North America

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  A map of the Great Lakes Basin showing the five sub-basins. Left to right they are: Superior (magenta); Michigan (cyan); Huron (green); Erie (yellow); Ontario (orange-red).

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  Chicago on Lake Michigan is in the western part of the lakes megalopolis and the site of the waterway linking the lakes to the Mississippi River valley

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  Detroit on the Detroit River links the region's central metropolitan areas

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  Lake Michigan–Huron with north oriented to the right; taken on April 14, 2022 during Expedition 67 of the International Space Station. Green Bay is at the upper right and Saginaw Bay is on the left.

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  South Bass Island in Lake Erie

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  Toronto on Lake Ontario is in the eastern section of the Great Lakes Megalopolis

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  Water levels of Lakes Michigan and Huron in the United States, 1918 to 2019.

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  A diagram of the formation of the Great Lakes

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  Map of Glacial Lake Algonquin and its Correlatives (USGS 1915)

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  The location of common lake effect bands on the Great Lakes

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  Lake sturgeon, the largest native fish in the Great Lakes and the subject of extensive commercial fishing in the 19th and 20th centuries is listed as a threatened species

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  Cliffs at Palisade Head on Lake Superior in Minnesota near Silver Bay.

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  A zebra mussel–encrusted vector-averaging current meter from Lake Michigan.

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  A woodcut of Le Griffon

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  The passenger ship SS Eastland (foreground) leaving Chicago, c. 1909

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  Photograph of Lakes Ontario, Erie and Huron plus the Finger Lakes of upstate New York, June 14, 2012, taken aboard the International Space Station, with lake names added

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  Escanaba's Ludington Park in Michigan

See also

In Spanish: Grandes Lagos (América del Norte) para niños