Great Lakes: the story on HearLore

Great Lakes

The Great Lakes contain 21 percent of the world's surface fresh water, a volume so vast that if it were spread evenly across the entire North American continent, it would create a layer five feet deep. This staggering quantity of water formed the foundation for a unique hydrological system that began its existence roughly 14,000 years ago when the Laurentide Ice Sheet retreated, leaving behind massive basins carved by glaciers. These basins filled with meltwater to create what are now known as Lake Superior, Lake Michigan, Lake Huron, Lake Erie, and Lake Ontario. While often treated as five distinct bodies of water, hydrologically Lake Michigan and Lake Huron function as a single lake connected by the Straits of Mackinac, where water levels rise and fall in unison and flow direction frequently reverses. The sheer scale of these inland seas has earned them the nickname of inland oceans, complete with rolling waves, sustained winds, and horizons so distant that sailors often mistake them for the open sea. The total surface area of the five lakes is roughly equal to the size of the United Kingdom, while the entire basin, including the land that drains into them, covers an area comparable to the combined size of the United Kingdom and France. This massive body of water serves as the primary drainage outlet for the interior of North America, connecting the continent to the Atlantic Ocean via the Saint Lawrence River and to the Mississippi River basin through the Illinois Waterway. The geography of the region is defined by the Niagara Escarpment, a geological feature that follows the contour of the lakes from New York to Wisconsin, creating dramatic cliffs and separating the upper lakes from the lower lakes. The upper lakes, which include Superior, Michigan, Huron, and Erie, sit at approximately the same elevation, while Lake Ontario sits significantly lower, creating a natural barrier to navigation that was only overcome by the construction of the Welland Canal and the St. Lawrence Seaway. The lakes are divided among the Canadian province of Ontario and eight U.S. states, creating a complex web of jurisdictional boundaries that has shaped the political and economic history of the region. Michigan possesses the longest shoreline of any U.S. state, bordering roughly 3,200 miles of lake water, while the total coastline of the Great Lakes measures approximately 9,000 miles, a distance equivalent to traveling halfway around the world at the equator. The region is home to approximately 35,000 islands, with the largest being Manitoulin Island in Lake Huron, which is itself large enough to contain multiple lakes, including Lake Manitou, the world's largest lake on a freshwater island. The islands and peninsulas of the Great Lakes, such as the Upper Peninsula of Michigan and the Bruce Peninsula in Ontario, have served as strategic points for trade, defense, and settlement for thousands of years. The water levels of the lakes have remained relatively constant over the 20th century, fluctuating only slightly due to changes in precipitation, evaporation, and human intervention, with record low levels observed in 2013 and record high levels in 2020. The annual ice coverage on the Great Lakes varies dramatically from year to year, ranging from as little as 10 percent to over 90 percent, with the particularly cold winter of 2013-2014 seeing ice coverage peak at over 92 percent. This ice cover creates a unique phenomenon known as ice volcanoes, where storm-generated waves carve the ice sheet and create conical mounds through the eruption of water and slush, a process well-documented only in the Great Lakes. The lakes also produce a weather pattern known as lake-effect snow, where prevailing winds pick up moisture from the relatively warm lake surface and deposit it as heavy snowfall on the colder land, creating snowbelts in Wisconsin, Indiana, Michigan, Ohio, Pennsylvania, New York, and Ontario. The moderating effect of the lakes on the regional climate allows for the cultivation of fruit and wine in areas that would otherwise be too far north, creating fruit belts in western Michigan, the Niagara Peninsula, and Prince Edward County. The Great Lakes have been observed to help intensify storms, such as Hurricane Hazel in 1954 and the 2011 Goderich, Ontario tornado, which moved onshore as a tornadic waterspout. The region is also prone to severe thunderstorms known as Mesoscale convective complexes, which can cause damage to wide swaths of forest and shatter glass in city buildings, often occurring at night with embedded tornadoes or straight-line winds accompanied by intense lightning. The Great Lakes are not just a body of water but a dynamic system that has shaped the climate, geography, and history of North America, serving as a vital resource for transportation, trade, and recreation for millions of people.

What percentage of the world's surface fresh water do the Great Lakes contain?

The Great Lakes contain 21 percent of the world's surface fresh water. This volume equals 6 quadrillion U.S. gallons and would create a layer five feet deep if spread evenly across the North American continent.

When did the Great Lakes form after the retreat of the Laurentide Ice Sheet?

The Great Lakes formed roughly 14,000 years ago when the Laurentide Ice Sheet retreated. This process left behind massive basins carved by glaciers that filled with meltwater to create the modern lakes.

Which Great Lake is the only one located entirely within the United States?

Lake Michigan is the only Great Lake located entirely within the United States. All other Great Lakes form a water boundary between the United States and Canada.

What year did the Edmund Fitzgerald sink on Lake Superior?

The Edmund Fitzgerald sank on the 10th of November 1975. This ship was the largest and last major freighter wrecked on the Great Lakes and disappeared just over 53 miles offshore from Whitefish Point.

How many islands are there in the Great Lakes and which is the largest?

The Great Lakes are home to approximately 35,000 islands. The largest of these is Manitoulin Island in Lake Huron, which contains multiple lakes including Lake Manitou.

The Geological Origins and Hydrological Secrets

The foundational geology that created the conditions shaping the present-day upper Great Lakes was laid from 1.1 to 1.2 billion years ago when two previously fused tectonic plates split apart and created the Midcontinent Rift, which crossed the Great Lakes Tectonic Zone. A valley was formed providing a basin that eventually became modern-day Lake Superior, while a second fault line, the Saint Lawrence rift, formed approximately 570 million years ago, creating the basis for Lakes Ontario and Erie along with what would become the Saint Lawrence River. The Great Lakes are estimated to have been formed at the end of the Last Glacial Period, when the Wisconsin glaciation ended 10,000 to 12,000 years ago, and the Laurentide Ice Sheet receded. The retreat of the ice sheet left behind a large amount of meltwater, including Lake Algonquin, Lake Chicago, Glacial Lake Iroquois, and the Champlain Sea, that filled up the basins that the glaciers had carved, thus creating the Great Lakes as they are today. Because of the uneven nature of glacier erosion, some higher hills became Great Lakes islands, and land below the glaciers rebounded as it was uncovered, a process known as glacial rebound that occurred at different rates since the glaciers covered some areas longer than others. The Niagara Escarpment follows the contour of the Great Lakes between New York and Wisconsin, creating dramatic cliffs and separating the upper lakes from the lower lakes. The lakes are divided among the Canadian province of Ontario and eight U.S. states, creating a complex web of jurisdictional boundaries that has shaped the political and economic history of the region. The surface area of the five primary lakes combined is roughly equal to the size of the United Kingdom, while the surface area of the entire basin is about the size of the United Kingdom and France combined. Lake Michigan is the only one of the Great Lakes that is entirely within the United States, while the others form a water boundary between the United States and Canada. The lakes are divided among the jurisdictions of the Canadian province of Ontario and the U.S. states of Michigan, Wisconsin, Minnesota, Illinois, Indiana, Ohio, Pennsylvania, and New York. Both the province of Ontario and the state of Michigan include in their boundaries portions of four of the lakes. The province of Ontario does not border Lake Michigan, and the state of Michigan does not border Lake Ontario. New York and Wisconsin's jurisdictions extend into two lakes, and each of the remaining states into one of the lakes. The Great Lakes contain 21 percent of the world's surface fresh water, or 6.0 times 10 to the 15th U.S. gallons, which is 6 quadrillion U.S. gallons. The lakes contain about 84 percent of the surface freshwater of North America, and if the water were evenly distributed over the entire continent's land area, it would reach a depth of 5 feet. This is enough water to cover the 48 contiguous U.S. states to a uniform depth of 10 feet. Although the lakes contain a large percentage of the world's fresh water, the Great Lakes supply only a small portion of U.S. drinking water on a national basis. The total surface area of the lakes is approximately 94,000 square miles, nearly the same size as the United Kingdom, and larger than the U.S. states of New York, New Jersey, Connecticut, Rhode Island, Massachusetts, Vermont, and New Hampshire combined. The Great Lakes coast measures approximately 9,000 miles. Canada borders approximately 4,500 miles of coastline, while the remaining 4,500 miles are bordered by the United States. Michigan has the longest shoreline of the United States, bordering roughly 3,200 miles of lakes, followed by Wisconsin, New York, and Ohio. Traversing the shoreline of all the lakes would cover a distance roughly equivalent to traveling half-way around the world at the equator. The lakes were originally fed by both precipitation and meltwater from glaciers which are no longer present. In modern times, only about 1 percent of volume per year is new water, originating from rivers, precipitation, and groundwater springs. In the post-glacial period, evaporation and drainage have generally been balanced, making the levels of the lakes relatively constant. Intensive human population growth began in the region in the 20th century and continues today. At least two human water use activities have been identified as having the potential to affect the lakes' levels: diversion and consumption. Outflows through the Chicago Sanitary and Ship Canal is more than balanced by artificial inflows via the Ogoki River and Long Lake/Kenogami River diversions. Fluctuation of the water levels in the lakes has been observed since records began in 1918. The water level of Lake Michigan-Huron had remained fairly constant over the 20th century. Recent lake levels include record low levels in 2013 in Lakes Superior, Erie, and Michigan-Huron, followed by record high levels in 2020 in the same lakes. The water level in Lake Ontario has remained relatively constant in the same time period, hovering around the historical average level. Although true tides, changes in water level caused by the gravitational forces of the sun and moon, do occur in a semi-diurnal pattern, such changes are quite small and generally obscured by other forces. The lake levels are affected primarily by changes in regional meteorology and climatology. The outflows from Lakes Superior and Ontario are regulated, while the outflows of Michigan-Huron and Erie are not regulated at all. Ontario is the most tightly regulated, with its outflow controlled by the Moses-Saunders Power Dam, which explains its consistent historical levels. The annual ice coverage on the Great Lakes varies greatly from year to year due to weather patterns and long-term climate trends. Ice typically begins forming in December and reaches its peak in February or early March. The extent of ice cover can vary from as little as 10 percent to over 90 percent depending on winter severity. For example, during the particularly cold winter of 2013-2014, ice coverage peaked at over 92 percent across the five lakes, while in milder years like 2023-2024, coverage remained below 20 percent. Long-term data from the National Oceanic and Atmospheric Administration's Great Lakes Environmental Research Laboratory indicate a general decline in maximum ice cover over the past few decades, aligning with broader patterns of warming in the region. A notable modern phenomenon is the formation of ice volcanoes over the lakes during wintertime. Storm-generated waves carve the lakes' ice sheet and create conical mounds through the eruption of water and slush. The process is only well-documented in the Great Lakes, and has been credited with sparing the southern shorelines from worse rocky erosion.

The Hidden Life Beneath the Waves

The Great Lakes are an important source of fishing, and early European settlers were astounded by both the variety and quantity of fish, with 150 different species in the Great Lakes. Throughout history, fish populations were the early indicator of the condition of the Lakes and have remained one of the key indicators even in the current era of sophisticated analyses and measuring instruments. According to the bi-national resource book, The Great Lakes: An Environmental Atlas and Resource Book, the largest Great Lakes fish harvests were recorded in 1889 and 1899 at some 147 million pounds. By 1801, the New York Legislature found it necessary to pass regulations curtailing obstructions to the natural migrations of Atlantic salmon from Lake Erie into their spawning channels. In the early 19th century, the government of Upper Canada found it necessary to introduce similar legislation prohibiting the use of weirs and nets at the mouths of Lake Ontario's tributaries. Other protective legislation was passed, but enforcement remained difficult. On both sides of the Canada-United States border, the proliferation of dams and impoundments have multiplied, necessitating more regulatory efforts. Concerns by the mid-19th century included obstructions in the rivers which prevented salmon and lake sturgeon from reaching their spawning grounds. The Wisconsin Fisheries Commission noted a reduction of roughly 25 percent in general fish harvests by 1875. The states have removed dams from rivers where necessary. Overfishing has been cited as a possible reason for a decrease in population of various whitefish, important because of their culinary desirability and, hence, economic consequence. Moreover, between 1879 and 1899, reported whitefish harvests declined from some 24.3 million pounds to just over 9 million pounds. By 1900, commercial fishermen on Lake Michigan were hauling in an average of 41 million pounds of fish annually. By 1938, Wisconsin's commercial fishing operations were motorized and mechanized, generating jobs for more than 2,000 workers, and hauling 14 million pounds per year. The population of giant freshwater mussels was eliminated as the mussels were harvested for use as buttons by early Great Lakes entrepreneurs. The Great Lakes: An Environmental Atlas and Resource Book notes that only pockets remain of the once large commercial fishery. Water quality improvements realized during the 1970s and 1980s, combined with successful salmonid stocking programs, have enabled the growth of a large recreational fishery. The last commercial fisherman left Milwaukee in 2011 because of overfishing and anthropogenic changes to the biosphere. The Great Lakes are an important source of fishing, and early European settlers were astounded by both the variety and quantity of fish, with 150 different species in the Great Lakes. The deep waters contain organisms found only in deep, cold lakes of the northern latitudes, including the delicate opossum shrimp, the deepwater scud, two types of copepods, and the deepwater sculpin. The Great Lakes are an important source of fishing, and early European settlers were astounded by both the variety and quantity of fish, with 150 different species in the Great Lakes. Since the 19th century, an estimated 160 new species have found their way into the Great Lakes ecosystem, many of which have become invasive. The overseas ship ballast and ship hull parasitism are causing severe economic and ecological impacts. According to the Inland Seas Education Association, on average a new species enters the Great Lakes every eight months. Introductions into the Great Lakes include the zebra mussel, which was first discovered in 1988, and quagga mussel in 1989. Since 2000, the invasive quagga mussel has smothered the bottom of Lake Michigan almost from shore to shore, and their numbers are estimated at 900 trillion. The mollusks are efficient filter feeders, competing with native mussels and reducing available food and spawning grounds for fish. In addition, the mussels may be a nuisance to industries by clogging pipes. The U.S. Fish and Wildlife Service estimated in 2007 that the economic impact of the zebra mussel could be about 5 billion dollars over the next decade. The state of Michigan has had to develop legislation and regulations to help protect against these invasive species. Aquatic invasive species regulations in Michigan have been put in place to combat the influx of species. The alewife first entered the system west of Lake Ontario via 19th-century canals. By the 1960s, the small silver fish had become a familiar nuisance to beach goers across Lakes Michigan, Huron, and Erie. Periodic mass die-offs result in vast numbers of the fish washing up on shore, with estimates by various governments placing the percentage of Lake Michigan's biomass which was made up of alewives in the early 1960s as high as 90 percent. In the late 1960s, the various state and federal governments began stocking several species of salmonids, including the native lake trout as well as non-native Chinook and coho salmon, and by the 1980s, alewife populations had dropped drastically. The ruffe, a small percid fish from Eurasia, became the most abundant fish species in Lake Superior's Saint Louis River within five years of its detection in 1986. Its range, which has expanded to Lake Huron, poses a significant threat to the lower lake fishery. Five years after first being observed in the St. Clair River, the round goby can now be found in all of the Great Lakes. The goby is considered undesirable for several reasons: it preys upon bottom-feeding fish, overruns optimal habitat, spawns multiple times a season, and can survive poor water quality conditions. The influx of parasitic sea lamprey populations after the development of the Erie Canal and the much later Welland Canal led to the two federal governments of the United States and Canada working on joint proposals to control it. By the mid-1950s, the lake trout populations of Lakes Michigan and Huron were reduced, with the lamprey deemed largely to blame. This led to the launch of the bi-national Great Lakes Fishery Commission. Several species of exotic water fleas have accidentally been introduced into the Great Lakes, such as the spiny waterflea and the fishhook waterflea, potentially having an effect on the zooplankton population. Several species of crayfish have also been introduced that may contend with native crayfish populations. More recently an electric fence has been set up across the Chicago Sanitary and Ship Canal in order to keep several species of invasive Asian carp out of the lakes. These fast-growing planktivorous fish have heavily colonized the Mississippi and Illinois river systems. Invasive species, particularly zebra and quagga mussels, may be at least partially responsible for the collapse of the deepwater demersal fish community in Lake Huron, as well as drastic unprecedented changes in the zooplankton community of the lake. Scientists understand that the micro-aquatic life of the lakes is abundant but know very little about some of the most plentiful microbes and their environmental effects in the Great Lakes. Although a drop of lake water may contain 1 million bacteria cells and 10 million viruses, only since 2012 has there been a long-term study of the lakes' micro-organisms. Between 2012 and 2019 more than 160 new species have been discovered. The fish of the Great Lakes have anti-depressant drugs meant for humans in their brains, which has caused concerns. The number of American adults who take anti-depressant drugs rose from 7.7 percent of all American adults in 1999-2002 to 12.7 percent in 2011-2014. As the anti-depressant drugs pass out of human bodies and through sanitation systems into the Great Lakes, this has resulted in fish in the Great Lakes with twenty times the level of anti-depressants in their brains than what is in the water, leading to the fish being exceedingly happy and hence less risk-averse, to the extent of damaging the fish populations. Researchers have found that more than 100 tons of plastic end up in the Great Lakes each year. Plastics in the water break up into very small particles known as microplastics. Microplastics can also come from synthetic clothing washed down the drains. Plastic waste found in the lakes include single-use plastics, plastics used in packaging, takeout containers as well as pre-production pellets produced by plastics industry. High concentrations of microplastics were discovered in 100 percent of the fish that were studied by researchers from the Rochman Lab. About 100 million pounds of fish is harvested each year from Great Lakes which has raised concerns on how this might affect human health. Microscopic pieces of plastic have also been found in drinking water coming from Great Lakes. It is estimated that nearly 40 million people in the region rely on drinking water from the Great Lakes. A number of self-operating floating devices called Seabin, were put in the Great Lakes to capture plastic trash as part of the Great Lakes Plastic Cleanup project. The project captured 74,000 pieces of trash using this technology between 2020 and 2021, however, it does not claim to catch up with 100 tons of plastic that ends up in Great Lakes every year. The production, consumption, and throwing away of plastics seems to remain the core of Great Lakes trash problem. The Great Lakes have been observed to help intensify storms, such as Hurricane Hazel in 1954 and the 2011 Goderich, Ontario tornado, which moved onshore as a tornadic waterspout. The region is also prone to severe thunderstorms known as Mesoscale convective complexes, which can cause damage to wide swaths of forest and shatter glass in city buildings, often occurring at night with embedded tornadoes or straight-line winds accompanied by intense lightning. The Great Lakes are not just a body of water but a dynamic system that has shaped the climate, geography, and history of North America, serving as a vital resource for transportation, trade, and recreation for millions of people.

The Graveyard of the Great Lakes

The large size of the Great Lakes increases the risk of water travel, and storms and reefs are common threats. Hundreds of ships have met their end on the lakes, with the greatest concentration of shipwrecks lying near Thunder Bay, Michigan, beneath Lake Huron, near the point where eastbound and westbound shipping lanes converge. The Lake Superior shipwreck coast from Grand Marais, Michigan, to Whitefish Point became known as the Graveyard of the Great Lakes, with more vessels lost in the Whitefish Point area than any other part of Lake Superior. The Whitefish Point Underwater Preserve serves as an underwater museum to protect the many shipwrecks in this area. The first ship to sink in Lake Michigan was Le Griffon, also the first ship to sail the Great Lakes. Caught in a 1679 storm while trading furs between Green Bay and Michilimacinac, she was lost with all hands aboard. Its wreck may have been found in 2004, but a wreck subsequently discovered in a different location was also claimed in 2014 to be Le Griffon. The largest and last major freighter wrecked on the lakes was the Edmund Fitzgerald, which sank on the 10th of November 1975, just over 53 miles offshore from Whitefish Point on Lake Superior. The largest loss of life in a shipwreck out on the lakes may have been that of the Eastland, wrecked in 1860 with the loss of around 400 lives on Lake Michigan. In an incident at a Chicago dock in 1915, the Eastland rolled over while loading passengers, killing 844. In 2007, the Great Lakes Shipwreck Historical Society announced that it had found the wreckage of Cyprus, a 400-foot-long, century-old ore carrier. Cyprus sank during a Lake Superior storm on the 11th of October 1907, during its second voyage while hauling iron ore from Superior, Wisconsin, to Buffalo, New York. The entire crew of 23 drowned, except one, Charles Pitz, who floated on a life raft for almost seven hours. In 2008, deep sea divers in Lake Ontario found the wreck of the 1780 Royal Navy warship HMS Royal Navy warship in what has been described as an archaeological miracle. There are no plans to raise her as the site is being treated as a war grave. In 2010, L.R. Doty was found in Lake Michigan by an exploration diving team led by dive boat Captain Jitka Hanakova from her boat Molly V. The ship sank in October 1898, probably attempting to rescue a small schooner, Olive Jeanette, during a terrible storm. Still missing are the two last warships to sink in the Great Lakes, the French minesweepers Inkerman and Cerisoles, which vanished in Lake Superior during a blizzard in 1918. 78 people died, making it the largest loss of life in Lake Superior and the greatest unexplained loss of life in the Great Lakes. The Wisconsin Shipwreck Coast National Marine Sanctuary was established in 2021 in the waters of Lake Michigan off Wisconsin. It is the site of a large number of historically significant shipwrecks. The Great Lakes have been observed to help intensify storms, such as Hurricane Hazel in 1954 and the 2011 Goderich, Ontario tornado, which moved onshore as a tornadic waterspout. The region is also prone to severe thunderstorms known as Mesoscale convective complexes, which can cause damage to wide swaths of forest and shatter glass in city buildings, often occurring at night with embedded tornadoes or straight-line winds accompanied by intense lightning. The Great Lakes are not just a body of water but a dynamic system that has shaped the climate, geography, and history of North America, serving as a vital resource for transportation, trade, and recreation for millions of people.

The Battle for Clean Water

The first U.S. Clean Water Act, passed by a Congressional override after being vetoed by U.S. President Richard Nixon in 1972, was a key piece of legislation, along with the bi-national Great Lakes Water Quality Agreement signed by Canada and the U.S. A variety of steps taken to process industrial and municipal pollution discharges into the system greatly improved water quality by the 1980s, and Lake Erie in particular is significantly cleaner. Discharge of toxic substances has been sharply reduced. Federal and state regulations control substances like PCBs. The first of 43 Great Lakes Areas of Concern to be formally de-listed through successful cleanup was Ontario's Collingwood Harbour in 1994, and Ontario's Severn Sound followed in 2003. Presque Isle Bay in Pennsylvania is formally listed as in recovery, as is Ontario's Spanish Harbour. Dozens of other Areas of Concern have received partial cleanups such as the Rouge River in Michigan and Waukegan Harbor in Illinois. Phosphate detergents were historically a major source of nutrient to the Great Lakes algae blooms in particular in the warmer and shallower portions of the system such as Lake Erie, Saginaw Bay, Green Bay, and the southernmost portion of Lake Michigan. By the mid-1980s, most jurisdictions bordering the Great Lakes had controlled phosphate detergents. Blue-green algae, or cyanobacteria blooms, have been problematic on Lake Erie since 2011. Not enough is being done to stop fertilizer and phosphorus from getting into the lake and causing blooms, said Michael McKay, executive director of the Great Lakes Institute for Environmental Research at the University of Windsor. The largest Lake Erie bloom to date occurred in 2015, exceeding the severity index at 10.5 and in 2011 at a 10. In early August 2019, satellite images depicted a bloom stretching up to 1,300 square kilometers on Lake Erie, with the heaviest concentration near Toledo, Ohio. A large bloom does not necessarily mean the cyanobacteria will produce toxins, said Michael McKay, of the University of Windsor. Water quality testing was underway in August 2019. Until 1970, mercury was not listed as a harmful chemical, according to the United States Federal Water Quality Administration. In the 21st century, mercury has become more apparent in water tests. Mercury compounds have been used in paper mills to prevent slime from forming during their production, and chemical companies have used mercury to separate chlorine from brine solutions. Studies conducted by the Environmental Protection Agency have shown that when the mercury comes in contact with many of the bacteria and compounds in the fresh water, it forms the compound methyl mercury, which has a much greater impact on human health than elemental mercury due to a higher propensity for absorption. This form of mercury is not detrimental to a majority of fish types, but is very detrimental to people and other wildlife animals who consume the fish. Mercury has been known for health related problems such as birth defects in humans and animals, and the near extinction of eagles in the Great Lakes region. The amount of raw sewage dumped into the waters was the primary focus of both the first Great Lakes Water Quality Agreement and federal laws passed in both countries during the 1970s. Implementation of secondary treatment of municipal sewage by major cities greatly reduced the routine discharge of untreated sewage during the 1970s and 1980s. The International Joint Commission in 2009 summarized the change: Since the early 1970s, the level of treatment to reduce pollution from waste water discharges to the Great Lakes has improved considerably. This is a result of significant expenditures to date on both infrastructure and technology, and robust regulatory systems that have proven to be, on the whole, quite effective. The commission reported that all urban sewage treatment systems on the U.S. side of the lakes had implemented secondary treatment, as had all on the Canadian side except for five small systems. Though contrary to federal laws in both countries, those treatment system upgrades have not yet eliminated combined sewer overflow events. This describes when older sewerage systems, which combine storm water with sewage into single sewers heading to the treatment plant, are temporarily overwhelmed by heavy rainstorms. Local sewage treatment authorities then must release untreated effluent, a mix of rainwater and sewage, into local water bodies. While enormous public investments such as the Deep Tunnel projects in Chicago and Milwaukee have greatly reduced the frequency and volume of these events, they have not been eliminated. The number of such overflow events in Ontario, for example, is flat according to the International Joint Commission. Reports about this issue on the U.S. side highlight five large municipal systems, those of Detroit, Cleveland, Buffalo, Milwaukee and Gary, as being the largest current periodic sources of untreated discharges into the Great Lakes. The fish of the Great Lakes have anti-depressant drugs meant for humans in their brains, which has caused concerns. The number of American adults who take anti-depressant drugs rose from 7.7 percent of all American adults in 1999-2002 to 12.7 percent in 2011-2014. As the anti-depressant drugs pass out of human bodies and through sanitation systems into the Great Lakes, this has resulted in fish in the Great Lakes with twenty times the level of anti-depressants in their brains than what is in the water, leading to the fish being exceedingly happy and hence less risk-averse, to the extent of damaging the fish populations. Researchers have found that more than 100 tons of plastic end up in the Great Lakes each year. Plastics in the water break up into very small particles known as microplastics. Microplastics can also come from synthetic clothing washed down the drains. Plastic waste found in the lakes include single-use plastics, plastics used in packaging, takeout containers as well as pre-production pellets produced by plastics industry. High concentrations of microplastics were discovered in 100 percent of the fish that were studied by researchers from the Rochman Lab. About 100 million pounds of fish is harvested each year from Great Lakes which has raised concerns on how this might affect human health. Microscopic pieces of plastic have also been found in drinking water coming from Great Lakes. It is estimated that nearly 40 million people in the region rely on drinking water from the Great Lakes. A number of self-operating floating devices called Seabin, were put in the Great Lakes to capture plastic trash as part of the Great Lakes Plastic Cleanup project. The project captured 74,000 pieces of trash using this technology between 2020 and 2021, however, it does not claim to catch up with 100 tons of plastic that ends up in Great Lakes every year. The production, consumption, and throwing away of plastics seems to remain the core of Great Lakes trash problem. The Great Lakes have been observed to help intensify storms, such as Hurricane Hazel in 1954 and the 2011 Goderich, Ontario tornado, which moved onshore as a tornadic waterspout. The region is also prone to severe thunderstorms known as Mesoscale convective complexes, which can cause damage to wide swaths of forest and shatter glass in city buildings, often occurring at night with embedded tornadoes or straight-line winds accompanied by intense lightning. The Great Lakes are not just a body of water but a dynamic system that has shaped the climate, geography, and history of North America, serving as a vital resource for transportation, trade, and recreation for millions of people.

The Inland Sea That Shaped a Continent

Several Native American populations, Paleo-indians, inhabited the region around 10,000 BC, after the end of the Wisconsin glaciation. The peoples of the Great Lakes traded from around 1000 AD, as copper nuggets have been extracted from the region and fashioned into ornaments and weapons in the mounds of Southern Ohio. The Rush-Bagot Treaty signed in 1818, after the War of 1812 and the later Treaty of Washington eventually led to a complete disarmament of naval vessels in the Great Lakes. Nonetheless, both nations maintained coast guard vessels in the Great Lakes. The brigantine Griffin, which was commissioned by René-Robert Cavelier, Sieur de La Salle, was built at Cayuga Creek, near the southern end of the Niagara River, and became the first known sailing ship to travel the upper Great Lakes on the 7th of August 1679. During settlement, the Great Lakes and its rivers were the only practical means of moving people and freight. Barges from middle North America were able to reach the Atlantic Ocean from the Great Lakes when the Welland Canal opened in 1824 and the later Erie Canal opened in 1825. By 1848, with the opening of the Illinois and Michigan Canal at Chicago, direct access to the Mississippi River was possible from the lakes. With these two canals an all-inland water route was provided between New York City and New Orleans. The main business of many of the passenger lines in the 19th century was transporting immigrants. Many of the larger cities owe their existence to their position on the lakes as a freight destination as well as for being a magnet for immigrants. After railroads and surface roads developed, the freight and passenger businesses dwindled and, except for ferries and a few foreign cruise ships, have now vanished. The immigration routes still have an effect today. Immigrants often formed their own communities, and some areas have a pronounced ethnicity, such as Dutch, German, Polish, Finnish, and many others. Since many immigrants settled for a time in New England before moving westward, many areas on the U.S. side of the Great Lakes also have a New England feel, especially in home styles and accent. Since general freight these days is transported by railroads and trucks, domestic ships mostly move bulk cargoes, such as iron ore, coal and limestone for the steel industry. The domestic bulk freight developed because of the nearby mines. It was more economical to transport the ingredients for steel to centralized plants rather than to make steel on the spot. Grain exports are also a major cargo on the lakes. In the 19th and early 20th centuries, iron and other ores such as copper were shipped south on downbound ships, and supplies, food, and coal were shipped north upbound. Because of the location of the coal fields in Pennsylvania and West Virginia, and the general northeast track of the Appalachian Mountains, railroads naturally developed shipping routes that went due north to ports such as Erie, Pennsylvania and Ashtabula, Ohio. Because the lake maritime community largely developed independently, it has some distinctive vocabulary. Ships, no matter the size, are called boats. When the sailing ships gave way to steamships, they were called steamboats, the same term used on the Mississippi. The ships also have a distinctive design; ships that primarily trade on the lakes are known as lake freighters or lakers. Foreign boats are known as salts. One of the more common sights on the lakes, since about 1950, has been the self-unloader, a laker with a conveyor belt system that can unload itself by swinging a crane over the side. Today, the Great Lakes fleet is much smaller in numbers than it once was because of the increased use of overland freight, and a few larger ships replacing many small ones. During World War II, the risk of submarine attacks against coastal training facilities motivated the United States Navy to operate two aircraft carriers on the Great Lakes, the USS Wolverine and the USS Sable. Both served as training ships to qualify naval aviators in carrier landing and takeoff. Lake Champlain briefly became the sixth Great Lake of the United States on the 6th of March 1998, when President Clinton signed Senate Bill 927. This bill, which reauthorized the National Sea Grant Program, contained a line declaring Lake Champlain to be a Great Lake. Not coincidentally, this status allows neighboring states to apply for additional federal research and education funds allocated to these national resources. Following a small uproar, the Senate voted to revoke the designation on March 24, although New York and Vermont universities would continue to receive funds to monitor and study the lake. Alan B. McCullough has written that the fishing industry of the Great Lakes got its start on the American side of Lake Ontario in Chaumont Bay, near the Maumee River on Lake Erie, and on the Detroit River at about the time of the War of 1812. Although the region was sparsely populated until the 1830s, so there was not much local demand and transporting fish was prohibitively costly, there were economic and infrastructure developments that were promising for the future of the fishing industry going into the 1830s. Particularly, the 1825 opening of the Erie Canal and the Welland Canal a few years later. The fishing industry expanded particularly in the waters associated with the fur trade that connect Lake Erie and Lake Huron. In fact, two major suppliers of fish in the 1830s were the fur trading companies Hudson's Bay Company and the American Fur Company. The catch from these waters was sent to the growing market for salted fish in Detroit, where merchants involved in the fur trade had already gained some experience handling salted fish. One such merchant was John P. Clark, a shipbuilder and merchant who began selling fish in the area of Manitowoc, Wisconsin where whitefish was abundant. Another operation cropped up in Georgian Bay, Canadian waters plentiful with trout as well as whitefish. In 1831, Alexander MacGregor from Goderich, Ontario found whitefish and herring in abundant supply around the Fishing Islands. A contemporary account by Methodist missionary John Evans describes the fish as resembling a bright cloud moving rapidly through the water. From 1844 through 1857, palace steamers carried passengers and cargo around the Great Lakes. In the first half of the 20th century large luxurious passenger steamers sailed the lakes in opulence. The Detroit and Cleveland Navigation Company had several vessels at the time and hired workers from all walks of life to help operate these vessels. Several ferries currently operate on the Great Lakes to carry passengers to various islands. As of 2007, four car ferry services cross the Great Lakes, two on Lake Michigan: a steamer from Ludington, Michigan, to Manitowoc, Wisconsin, and a high speed catamaran from Milwaukee to Muskegon, Michigan, one on Lake Erie: a boat from Kingsville, Ontario, or Leamington, Ontario, to Pelee Island, Ontario, then onto Sandusky, Ohio, and one on Lake Huron: the MS Chi-Cheemaun runs between Tobermory and South Baymouth, Manitoulin Island, operated by the Owen Sound Transportation Company. An international ferry across Lake Ontario from Rochester, New York, to Toronto ran during 2004 and 2005 but is no longer in operation. Except when the water is frozen during winter, more than 100 lake freighters operate continuously on the Great Lakes, which remain a major water transport corridor for bulk goods. The Great Lakes Waterway connects all the lakes; the shorter Saint Lawrence Seaway connects the lakes to the Atlantic Ocean. Some lake freighters are too large to use the Seaway and operate only on the Waterway and lakes. In 2002, 162 million net tons of dry bulk cargo were moved on the Lakes. This was, in order of volume: iron ore, grain and potash. The iron ore and much of the stone and coal are used in the steel industry. There is also some shipping of liquid and containerized cargo. Major ports on the Great Lakes include Duluth-Superior, Chicago, Detroit, Cleveland, Twin Harbors, Hamilton and Thunder Bay. Tourism and recreation are major industries on the Great Lakes. A few small cruise ships operate on the Great Lakes including some sailing ships. Sport fishing, commercial fishing, and Native American fishing represent a U.S. 4 billion a year industry with salmon, whitefish, smelt, lake trout, bass and walleye being major catches. Many other water sports are practiced on the lakes such as yachting, sea kayaking, diving, kitesurfing, powerboating, and lake surfing. The Great Lakes Circle Tour is a designated scenic road system connecting all of the Great Lakes and the Saint Lawrence River. In 1872, a treaty gave access to the St. Lawrence River to the United States and access to Lake Michigan to the Dominion of Canada. The International Joint Commission was established in 1909 to help prevent and resolve disputes relating to the use and quality of boundary waters, and to advise Canada and the United States on questions related to water resources. Concerns over diversion of Lake water are of concern to both Americans and Canadians. Some water is diverted through the Chicago River to operate the Illinois Waterway, but the flow is limited by treaty. Possible schemes for bottled water plants and diversion to dry regions of the continent raise concerns. Under the U.S. Water Resources Development Act of 1986, approved the 17th of November 1986, diversion of water from the Great Lakes Basin requires the approval of all eight Great Lakes governors through the Great Lakes Commission, which rarely occurs. International treaties regulate large diversions. In 1998, the Canadian company Nova Group won approval from the Province of Ontario to withdraw 190 million gallons of Lake Superior water annually to ship by tanker to Asian countries. Public outcry forced the company to abandon the plan before it began. Since that time, the eight Great Lakes Governors and the Premiers of Ontario and Quebec have negotiated the Great Lakes-Saint Lawrence River Basin Sustainable Water Resources Agreement and the Great Lakes-St. Lawrence River Basin Water Resources Compact that would prevent most future diversion proposals and all long-distance ones. The agreements strengthen protection against abusive water withdrawal practices within the Great Lakes basin. On the 13th of December 2005, the Governors and Premiers signed these two agreements, the first of which is between all ten jurisdictions. It is somewhat more detailed and protective, though its legal strength has not yet been tested in court. The second, the Great Lakes Compact, has been approved by the state legislatures of all eight states that border the Great Lakes as well as the U.S. Congress, and was signed into law by President George W. Bush on the 3rd of October 2008. The Great Lakes Restoration Initiative was funded at 475 million dollars in the U.S. federal government's Fiscal Year 2011 budget, and 300 million dollars in the Fiscal Year 2012 budget. Through the program a coalition of federal agencies is making grants to local and state entities for toxics cleanups, wetlands and coastline restoration projects, and invasive species-related projects. The Great Lakes Restoration Initiative Act of 2019 passed as H.R. 2000 on the 5th of January 2021, reauthorizing the program through Fiscal Year 2026.