Great Lakes North America. Nature North America

Great Lakes (English. Great Lakes, Fr. Grands Lacs, sometimes the great Lavrentian lakes) - a system of freshwater lakes in North America, in the United States and Canada (Lake Michigan is entirely in the United States, on the rest of the lakes and connecting their short rivers. and Canada. Includes a number of large and medium water bodies connected by rivers and straits.

Actually, great lakes include the five largest: upper, guron, Michigan, Erie and Ontario, although sometimes the Saint Claire lakes are included in them, they form the largest group of freshwater lakes on Earth (total area 244 106 km², total volume 22 671 km³ ), containing 21% of the surface in the world of fresh water (and 84% of fresh water reserves of North America). Several medium-sized lakes are connected with them, the most important of which are: Saint Meris, Manitu, Napiga, Nipissing. Lakesthe atlantic ocean pool, the stock on the river of St. Lawrence.

Tectonic processes have the greatest impact on the formation of lake boiling; Great Lakes They began to form at the end of the last glacial period, about 10,000 years ago, when the mass of the glacier produced the earthly bark, and after the glacier was melted, a slow reverse process began - glaciizostasiya, which is also very noticeable in the area of \u200b\u200bthe Boat Bay and Finland. The water mass of lakes was formed when the glacier melting.

The northern coast of the Great Lakes rises faster than southern, which leads to the effect of "transfusion" of water and the slow flooding of lands in the south. Previously, great lakes had additional stock through the current River Illinois and Ottawa, but due to the same geological processes, they, being and so on near the banks of the lakes, changed their channel somewhat and radically changed the source. As a result of this, today natural stock exists only on the river of St. Lawrence.

Shipping and fisheries are developed here. With the help of the channels, a waterway for maritime ships with a length of about 3000 km is formed. Great lakes are connected by channels with the Hudson River and the Mississippi River Basch.
Main ports: Chicago, Milwaukee, Detroit, Cleveland, Buffalo, Toronto.

Great lakes are among the largest clusters of fresh water on Earth. Only Baikal and Greenland and Antarctica glaciers can compete with them. They are interconnected by rivers and channels, and therefore water flows from one to another. The upper lake is the largest on the area of \u200b\u200bthe Freshwater Lake Planet, and Ontario only one of the largest Lake Ladoga in Europe. The average depth of them, not being very large, surpasses the middle depth of the Baltic and North Seas.

The length of the coastline (with the islands) about 18 thousand km. The total area of \u200b\u200b244 106 km², the pool area is 768 thousand km² (including the area of \u200b\u200bthe lakes themselves), the total volume of 22,671 km³, in the four lakes of depths exceed 200 m and only the lake Ery the greatest depth of 64 m, and Saint Claire is only 8. The largest and most profound from the Great Lakes is the top lake, the smallest - Lake St. Claire.

There are several hundred mines of small rivers in the Great Lakes, the stock of lakes takes place along the St. Lawrence River, arising from Ontario lake and flowing into the Atlantic Ocean; The average water consumption in its source is 6637 m³ / s.

Previously, waste paper and other factories were discharged into these lakes. Initially, Lake Erie turned out to be significantly contaminated, it turned out with a snack, many types of fishing fish were missing from it. The government allocated significant funds for the cleaning of lakes. Now the lakes are again clean. Great lakes are very important leisure and shipping facilities.

Due to the directions of the wind in the cold seasons in the southern and eastern banks of the lakes, the snow effect of the lake is manifested.

The water level in Lake Michigan remained almost constant for the twentieth century. According to Georgue John King from the University of Rod Island, the water level is sensitive to climate change and can change more sharply in the XXI century.

In January 2013, the Lake Level Michigan and Huron updated the record (from the moment of regular observations, 1918) a low water level (before this minimum was recorded in March 1964), about 2 meters below the maximum level (October 1986). There are several reasons for this: dredging work, mining, and soil erosion.

About 35,000 islands are scattered in great lakes. The largest among them are Manitulin in Lake Huron, the largest island of the world, located in a fresh lake (area more of Luxembourg Square); Inside it has its own lake - Manitis, inside which there are also several islets. Another major island is Air-Royal on the top lake.

The fundamental tectonic processes that have formed great lakes took place from 1.1 to 1.2 billion years ago, when two previously connected tectonic plates separated from each other and created the middle-continental rift.

Great lakes were estimated to be formed at the end of the last ice age (about 10,000 years ago), when the Lavrentian glacial shield retreated. The retreat of the glacier left behind a large number of melt water, which filled out pools carved with glaciers.

On the North American continent there is a beautiful corner of nature, known as the Great Lakes. The pool of these reservoirs is considered one of the largest water treatment systems on our planet. It takes a rather impressive territory - 768 thousand km². It contains almost 18% of the entire global stock of fresh water! For information on where the great lakes are located, their origin and description can be found in this article.

History of origin

Scientists believe that about 12 thousand years ago, an icy desert was located on the site of North America. The origin of the Great Lakes is associated with the formation of tectonic depressions, which were subsequently fallen and deepened with a giant glacier, slowly shifted from the north to south. Huge masses of ice subposimal under themselves the soil consisting mainly of soft sandstone and clay slate. They easily destroyed the mountains and shifted huge boulders from the spot, as a result of which they were formed even deeper depressions and Moraine. Thus, wide pitchers were formed, which, after the melting of glaciers, were gradually filled with water.

General

This largest catchment system is located in North America, in the Pool of St. Lawrence, on the border of the two states - the United States and Canada. Great lakes are a group of five largest water bodies, which includes the top, Huron, Michigan, Erie and Ontario. The total length of their coastline is approximately 18 thousand km. They contain more than 22 thousand km³ of water, and their surface area is 245.3 thousand km². Lake Michigan is located in the United States. As for the rest of the reservoirs and connecting their rivers, then the border with Canada is passed on them.

The System of the Great Lakes is special, as it is located in the form of steps. The difference in the height of the placement of Upper, Guron, Michigan and Ery is no more than 9 m. But as for the lake. Ontario, then it is located compared to the rest below almost 100 m. Between themselves, all of the above reservoirs are connected by small, but rather full-flow rivers. Thus, the top with Guron is reported through the Saint Meris river 112 km long, and Ontario and Erie - through the Niagara, forming the same world-famous waterfall, the height of which is about 50 m. In addition, Huron is connected to ERI 43-kilometer Saint Claire, And with the lake Michigan - the Strait of Machino, whose width is at least 3 km.

The proximity of the settlements

Great lakes (on the map it is clearly visible) are replenished due to several hundred minor rivers, and the stock is carried out along the St. Lawrence River, arising from Ontario directly to the Atlantic Ocean. These waters have very small mineralization - just up to 0.13 g / l. In the system of these lakes there are about 170 different types of fish, including salmon, ocupal, trout, carp, sigay and many others.

It must be said that the area of \u200b\u200bthe Great Lakes in the South and Southeastern Piece is adjacent to very densely populated and industrially developed, and from the West and the North - to the agrarian-raw material territories of Canada and the United States. So, in the United States on the shores of Michigan, there are two largest cities - Milwaukee and Chicago, near Erie - Cleveland and Buffalo, and Near Ontario - Canadian Toronto. In addition, the lakes are communicated with the Mississippi Pool with a whole system of shipping channels.

Top

The largest freshwater area on the territory of North America is the top lake. By the amount of fresh water, this giant ranks third after the Russian Baikal and African Tanganiki. The average depth of the greatest American lake is 147, and the maximum is 406 meters. It contains more than 11 thousand km³ of water.

Upper Lake North Coast is located in Ontario Province (Canada). The rest of the coast is located in the United States. From the Western part of it, the lands of Minnesota state, from South-Michigan, and from South-West - Wisconsin. The total length of the coastline is 4387 km. The width of this freshwater giant reaches 260, and the length is 560 km. This reservoir is located at an altitude of 182 m above sea level.

It is worth noting that the coastline of the top lake is quite strongly cut with numerous bays and bays. The southern coast has a plain landscape and sand-covered beaches. This picturesque place was chosen by the inhabitants of the North American continent, who seek to come here with their families on vacation. As for the northern coast, it is completely consisting of some rocks and cliffs.

All the great American lakes feed on a large number of medium and small rivers. For example, in approximately two hundred and the largest - r. Napigiga. In addition, the lake has its own islands. The greatest of them is Isle Royal, the length of which is 72, and the width is 14 km. Now in the territory of this island there is a national park associated with the mainland constantly cruising there and back ferries.

Huron

For some time, some geographers are trying to combine this lake with the third largest reservoir - Michigan. Such attempts are explained by the fact that they are on the same level. These rather impressive water masses are very similar to two reporting vessels with similar characteristics. Huron is the second largest reservoir, which is part of the Great Lakes. It covers an area without a small 6 thousand km². Regarding the volume of fresh water, then it is inferior to Lake Michigan and amounts to 3,538 thousand km³. Located Huron 177 m above sea level.

The average depth of the lake does not exceed 60, and the maximum reaches 230 m. Its coastline is equal to 6,157 thousand km, while the length is 332, and the width is 295 km. In the northern part of Guron is a big island called Manitulin. It is considered the largest of all that are located in fresh reservoirs. Its area is 2.766 thousand km ². In addition, people live on it. The population of this island is approximately 13 thousand people.

The Great Lakes of North America has always been famous for a large number of rare fish species. Over time, they began to breed them in other fresh reservoirs around the world. Take at least a lake trout. She lives at a depth of 20 to 60 m. Unfortunately, in the mid-1950s, this type of fish was almost completely destroyed. And it's not just an excessive catch, but in the appearance of Guron's marine lampsion in the waters, which came here due to the opening of a new channel in 1925.

This lake is extremely famous primarily by the fact that it has frequent storms and storms on it, after which numerous ship cemeteries were formed. Judge themselves, from the beginning of the XVIII century, its water was absorbed more than one thousand ships! According to the documents, the first sunken ship was "Griffin". His wreck occurred in September 1679. He walked with a large flush car. But the most widely known event is the Great Storm that happened on the Great Lakes in 1913. It was a real hurricane, who focused on four days in the area. The strongest of this element suffered by Huron. In his waters, the element found 36 ships, most of them threw ashore, but 10 ships sank along with the crews. The victims of the great storm were 235 sailors.

On Lake Huron, there is a small signet bay located in the southwestern part of the reservoir. Here on the bottom resting 185 sunken ships. Other large ship cemetery is located near Manitulin Island. 212 ships buried there. Almost all of them were freight transport that was transported to the fur, grain or other goods, so the damage from their crashes was not one million dollars.

Michigan

This lake is the third largest freshwater reservoir and, unlike his fellow, who is fully in the United States. As mentioned above, all the great lakes of North America are located steps. This reservoir is located, like Huron, 177 m above sea level. Its average depth is 85, and the maximum - 281 m. Michigan lake takes about 58 thousand km². The length of its coastline is 2636, the width is 190, and the length is 494 km. The largest island of Lake Michigan is Beaver. Its length is 21, and the width is 10 km. It enters the same archipelago of the same name with a lot of smaller islands.

Four states are adjacent to this water: Illinois, Michigan, Wisconsin and Indiana. Along the entire coastline, about 12 million people live. The largest coastal cities are Milwaukee and Chicago. Lake Michigan in the summer is very popular with holidaymakers. It is famous for its beaches with a clean, soft and slightly embroidered under the legs. Such a feature is obliged to large quartz content. In addition, the formation of sand dunes is observed on the Michigan coast. As for the local water temperature, it remains warm even on the outcome of the summer.

From the north, lake coast are often covered by whole colonies of coral stones. Often their surface is covered with rather original and peculiar patterns, which distinguishes data from natural education from all known ordinary pebbles. Almost all the eastern coast of Lake Michigan is covered with cliffs, while southern - dunes. Such a feature can be explained by the predominance in these places of Western winds. It is they who in winter contribute to the formation of a rather impressive layer of ice on the surface of the lake.

Erie

This is the fourth largest reservoir included in the top five of the Great Lakes. It covers an area of \u200b\u200b25.7 thousand km². Erie stretched 388 km, and its width is a little more than 90 km. This is the smallest reservoir, the average depth of which is only 64 m. This lake is located in the territory of the three US states - Ohio, New York and Pennsylvania, as well as in the province of Ontario (Canada). In the southwestern part of it are numerous islands. On the coast of Erie, there are several major cities, such as Buffalo, Cleveland, Toledo and others.

As you know, great American lakes together and individually are unique corners of nature. Not exceptions and Erie. The climate is really unusual here. We are talking about the so-called snow effect. It arises due to the circulation of cold air masses in the winter months over warm lake water. By reaching a buffalo, he literally feels a huge amount of snow on the city. The snow effect is a short-term phenomenon that disappears when the ERI freezing.

Ontario

Its area is 19.5 thousand km². It is the smaller of the Great Lakes. Its average depth is 86, and the maximum - 244 m. Despite its relatively small sizes, Ontario is an essential transport artery of both Canada and the United States. Thanks to its great depth, this lake never completely freezes, so the courts run here all year round.

Since Ontario is located below all the great lakes, that is, only 75 m above the sea level, for convenient shipping, a large number of gateways were equipped, which have limited widths. This could lead to a significant reduction in freight. So that this does not happen, we developed the so-called lake trucks, which are the greatest river vessels in the world reaching the length of up to three hundred meters.

Ontario, like all of the above-mentioned Lakes, has a special climate. The local conditions contribute to the successful development of agriculture, as the spring blossoms of plants are delayed here, as well as overwhelmed fruits, such as peaches, plums, apples and cherries, are saved up to deep autumn. Even on this coast, grapes are growing perfectly, from which they make a delicious and fragrant drink.

Abuse

The large-scale and reckless use of these unique reservoirs in the United States and Canada could not help but lead to fairly serious socio-economic and environmental problems, and above all to pollution not only superficial, but also groundwater.

Especially detrimental to the Great Lakes influenced the economy of the United States intensively developing after World War II. It was at that time that the growth of the American industry began to learn. Industrial, household and other estates, without any cleaning, were pouring into these water bodies. The result of such actions was a sharp decrease in the oxygen content, and as a result, the mass death of the fish.

By that time, the use and further discharge of toxic chlorine-containing components and synthetic fertilizers led to their ingress in food. By the end of the 60s of the last century, about 40% of all the aquatic systems of the United States became unsuitable for both fishing and swimming people due to emergency contamination. Moreover, quite large volumes of toxic fluids fell into great lakes. The United States, therefore, became the main cause of the environmental catastrophe in the area.

By the way, already in the 70s of the last century, Lake Erie due to intensive discharges of the chemical industry turned out to be practically "dead." All this happened through the fault of enterprises, which did not pay due attention to high-quality wastewater treatment. As a result of the water, the Lake Erie was oversaturated with phosphorus, causing excessive flowering of algae, and as a result - a significant reduction in fish population.

Ecological situation

Once on the coasts of the largest freshwater lakes of the North American continent, many different animals lived, and their waters literally born with a variety of fish species. All this was very detailed and fascinatingly wrote in not so distant past, James Fenimor Cooper in his works "St. John's wort" and "tracker, or on the shores of Ontario." Since then, the herds of noble wild deer disappeared, thickets of thick deciduous forests, and with them the Indian tribes. The American lakes themselves turned into an ecologically unfavorable zone.

Despite the fact that the US and Canadian government make tremendous efforts to protect the natural wealth of the Great Lakes, it still does not bring any significant changes for the better. While there will be a variety of metallurgical, chemical and refinery enterprises near this water system, they will inevitably destroy the ecosystem of these unique reservoirs.

The greatest system of freshwater lakes of the United States and Canada is represented by 5 closely connected with vast reservoirs, which occupy an area of \u200b\u200b245 thousand km2 (water volume of 23 thousand km3). The lakes are located in a step by order from the upper lake to Lakes Huron, Michigan, Erie, Ontario, descending to the Atlantic, and interconnected network of small rivers and straits.

See where there are great American lakes on the world map:

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The most cold and largest among the great lakes of North America is considered a lake top. With harsh, almost intact man shores, it strikes with its size - 85 thousand km2 and depth - up to 406 m. It is famous for the top and steep temper, in stormy weather, his waves can reach 12 meters. The north coast has a particularly inaccessible look, where the ripples are covered with pine forests and lichen.

The second largest among the Great Lakes of the United States and Canada is Lake Huron. From his fellow, it is distinguished by unusual outlines of the coast. The northern part of Guron Rocky, with steep shores, separated from the main part of Manitulin Island. In the Gulf of Georgian - Bay many stony islets, rocks and volcanoes. In the southern part of the Bay, the shore is represented by sandy beaches. In some places you can see 300 - meter limestone cliffs so-called "Blue Mountains". Lake covers an area of \u200b\u200b59 thousand km2, depth - 228 m.

Michigan Lake will be connected to about. Huron is a wide strait, over which the world's longest bridge (8 km) rises. The outlines of the shores of the reservoir are straightforward. The northern part is wild and eminent. The southern part of the coast is thick populated (Chicago). The area of \u200b\u200bthe third largest reservoir of the Great Lakes of North America is 58 thousand km, depth - 281 m.

Lake Erie is surrounded by more picturesque landscapes, lively numerous national parks and reserves. Point Reserve - Pele is one of the unique places on the continent, where extensive swamps with a kind of fauna are preserved. Southeast and northern shores of gentle and sandy. South Coast is thickly populated, there are large industrial cities in the United States: Cleveland, Tolido, Buffalo. The North Canadian shore is in a lesser extent. From Lake Erie, the full-flowed River Niagara flows, on which 48 meter Niagara Falls is formed. Lake Square Michigan 58 thousand km2, maximum depth of 281 m.

Ontario lake is the smallest lake system of the Great Lakes. Its area is only 19 thousand km2, but it is rather deep (maximum depth of 244 m). Shores low and gentle, places covered with deciduous forest. Southeast is often encouraging rocks. On the northern Canadian coast are large cities: Toronto, Hamilton, Ottawa. In the region, many US National Parks and Canada. The lake flows from the River St. Lawrence, which flows from the Great Lakes to the Atlantic.

Schematic map of great lakes

Water levels in great lakes

Tectonic processes have the greatest impact on the formation of lake boiling; Great lakes began to form at the end of the last glacial period, about 10,000 years ago, when the mass of the glacier sold the earthly bark, and after the glacier was melted, a slow reverse process began - glaciizostasiya, which is also very noticeable in the area of \u200b\u200bthe Boat and Finland. The water mass of lakes was formed when the glacier melting. The northern coast of the Great Lakes rises faster than southern, which leads to the effect of the "transfusion" of water and the slow flooding of the lands in the south. Previously, great lakes had additional stock through the current River Illinois and Ottawa, but due to the same geological processes, they, being and so on near the banks of the lakes, changed their channel somewhat and radically changed the source. As a result, today the natural stock exists only on the river of St. Lawrence.

Geography

General

Great lakes are among the largest clusters of fresh water on Earth. Only Baikal, Green African Lakes and Greenland Glaciers and Antarctica can compete with them. They are interconnected by rivers and channels, and therefore water flows from one to another. The upper lake is the largest on the area of \u200b\u200bthe Freshwater Lake Planet, and Ontario only one of the largest Lake Ladoga in Europe. The average depth of them, not being very large, surpasses the middle depth of the Baltic and North Seas.

The length of the coastline (with the islands) about 18 thousand km. The total area of \u200b\u200b244 106 km², the pool area is 768 thousand km² (including the area of \u200b\u200bthe lakes themselves), the total volume of 22,671 km³, in the four lakes of depths exceed 200 m and only the lake Ery the greatest depth of 64 m, and Saint Claire is only 8. The largest and most profound from the Great Lakes is the top lake, the smallest - Lake St. Claire.

There are several hundred mines of small rivers in the Great Lakes, the stock of lakes takes place along the St. Lawrence River, arising from Ontario lake and flowing into the Atlantic Ocean; The average water consumption in its source is 6637 m³ / s.

Previously, sewage waste, paper and other factories were reset to these lakes. Initially, Lake Erie turned out to be significantly contaminated, it turned out with a snack, many types of fishing fish were missing from it. The government allocated significant funds for the cleaning of lakes. Now lakes are relatively clean. Great lakes are very important leisure and shipping facilities.

According to Georgue John King from the University of Rod Island, the water level is sensitive to climate change and can change more sharply in the XXI century.

In January 2013, the Lake Level Michigan and Huron updated the record (since the start of regular observations, 1918) a low water level (before this minimum was recorded in March 1964), about 2 meters below the maximum level (October 1986). There are several reasons for this: dredging work, mining, and soil erosion.

Islands

About 35,000 islands are scattered over great lakes. The largest among them are Manitulin in Lake Huron, the largest island of the world, located in a fresh lake (area more of Luxembourg Square); Inside it has its own lake - Manitis, inside which there are also several islets. Another major island is Air-Royal on the top lake.

Lakes

Upper lake

Huron

Michigan

Erie

Ontario

Geology

The fundamental tectonic processes that have formed great lakes took place from 1.1 to 1.2 billion years ago, when two previously connected tectonic plates separated from each other and created the middle-continental rift.

Great lakes were estimated to be formed at the end of the last ice age (about 10,000 years ago), when the Lavrentian glacial shield retreated. The retreat of the glacier left behind a large number of melt water, which filled out pools carved with glaciers.

When the glacier retreat was first cleaned by the Ice of Lie Michigan and Erie. In their place, the lakes appeared one after another Chicago, Mom., Whitlsi. With a common drain into the Mississippi River Pool. When Ontario and Huron lakes were cleared of ice, lake was formed in their place. Algonquin With stock in Lake Erie. During the greatest development, the area of \u200b\u200bLake Algonkin reached 250 thousand km². With the retreating of the glacier lake Ontario formed as a separate reservoir - lake Iroquis - With a runoff across the Mogauh River in the Hudson River and Next to the Atlantic Ocean. Further retreating of the glacier opened stock across the river of St. Lawrence.

Climate

The climate of the Great Lakes is wet, moderate type, similar to the climate of the middle Baltic. For the area of \u200b\u200bthe Great Lakes are characterized by sharp differences of meteo conditions. This is due to the proximity of such different areas as cold hackons bay in the north and very warm Mexican bay in the south. The most variable season is winter, it is snowy, the active activity of cyclones is observed. With cyclones, frequent invasions of the arctic air are connected and frequent invasions at this time leading to a sharp cooling, while sometimes in a matter of hours are riveted with ice important for navigation. In winter, at first ice covers the lake top, then - Huron and Michigan, last time - Erie. Lakes are not completely mesh, but navigation stops, becoming impossible from December to April. Spring lasts long, freaks are frequent. Summer is cool, it, like winter, volatile, with frequent rains and strong wind. Autumn includes a period of up to two weeks, called "

Great Lakes (Great Lakes), the world's largest lake system in the eastern part of North America, in the Pool of the River of St. Lawrence. Includes freshwater lakes top, Michigan, Huron, Erie and Ontario (see Table 1). Michigan Lake is entirely located in the United States, on the rest of the lakes and the border between the United States and Canada, which belongs to about 1/3 of the waters of the Great Lakes.

The total area of \u200b\u200bthe Great Lakes is 244.8 thousand km 2, the total amount of water is 22.7 thousand km 3 (21% of the global stock of freshwater). The length of the coastline is over 15 thousand km. Lakes are interconnected by short, thorny and multi-water rivers: the top and guron - the Saint Meriss River (length 112 km); Huron and Erie - the Saint Claire River (43 km), through the Saint Claire lake (area of \u200b\u200b1275 km 2) and the Detroit River (51 km); Erie and Ontario - the Niagara River (54 km), forming the Niagara Falls. From Michigan to Huron, water enters through the strait of McIno wide about 3 km. Several hundred minor rivers with a total area of \u200b\u200bcatchment of 525 thousand km 2, the largest - Escanoba, Kalamazu, Grand River, Maskigon, Manistee, O-Secl, Sagino, Momi, Muskigan, Momi. The stock of the lake aquatic masses (210 km 3 / year) occurs along the River of St. Lawrence, arising from Ontario, it is regulated by the hydrogen case of Iroquoa, located between its source and the mouth of its largest tributary - the Ottawa River.

The basins of the Great Lakes arose as a result of tectonic movements, smadic river and glacial erosion. The bowls of the top and northern part of Lake Huron were developed in the crystal rocks of the southern edge of the Canadian shield of the North American platform, the rest of the lakes in the thickness of Paleozoic limestone, the Dolomites and sandstones of the platform cover. After cutting the glacial cover, the steep shores are converted by wave abrasion. Along the shallow and protected areas of the coast sections, beaches, currency and gravel-sandy braids were formed. In the northern part of the Great Lakes, the coastline is disseminated, the coast (height of up to 400 m) rocky, incisive, very picturesque, especially the lakes top and guron. The southern shores are predominantly low, clay and sandy. The largest island throughout the waters of the Great Lakes - Manitulin Square over 1000 km 2 (Lake Huron).

The climate of the region of the Great Lakes is moderately continental. The average air temperatures in January on the top -8 ° C lake, on the south bank of ERI -3 ° C, in July, respectively, 19 and 22 ° C. Precipitation 700-800 mm per year.

In the nutrition of the lake, the upper amount of atmospheric precipitates exceeds the flow of river water, therefore its water mass is least mineralized. In the water balance of other lakes, it is more significant than the role of the river flow and the influx of water from the above lakes. Evaporation from the surface of the lakes about 165 km 3 / year (20% less than the drain into the river of St. Lawrence). The last 150 years of the amplitude of fluctuations in the water level in great lakes is ± 2 m, its intra-year oscillations is not more than 0.3 m due to the flow control by hydraulic dishes. Safety-rolled aqueous surfaces reach 3-4 m (top, michigan). Great Lakes freeze mainly off the coast (from December - January to March - April). In the central part, due to winter storms, ice cover is missing, only on Ontario occasionally there is a solid ice station. Duration of navigation 8-9 months a year. Water stratified water stratification is poorly expressed. In the spring and autumn there is a convective mixing of lakety water to the bottom. The average temperature of surface waters in August 18-22 ° C. Water in lakes have low mineralization (72-232 mg / l) (see Table 2).

In Michigan, Upper and Gurone, the composition of the most common species of plankton and benthos is similar. In phytoplankton, diatoms of algae are dominated, from semi-duty macrophytes - reed, chain, reed, sinth, from shipped - hike and half-eyed algae. Zooplankton consists mainly of Bosmin, Daphny and Cappon, Zoobentos - from the oligochet, mollusks. In Ery and Ontario in phytoplankton, cyanobacteria predominate, diatoms, green and dinophyte algae, from macrophytes - Rogoz, Ugut, RDESTs, in Zoobenthos - Hironomides (Moth). In all the great lakes there are barks, yellow perch, alosema, light skid, in Gurone, Upper and Michigan - Kizhuhu, Chavik, Goles-Quistiviromer and Sig Feldovoid. On the coast of the lake top - Park of Takuenon Falls; Isle Isle-Royal (upper) - as part of the National Park of the eponymous; Between the Upper and Michigan - the reserve of Seine.

The HPP system of the Great Lakes is produced 50 billion kWh energy per year. Total water consumption from the Great Lakes by the end of the 20th century exceeded 20 km 3 year. From 40 to 70% of the water taken from the lakes, TPPs and nuclear power plants were consumed, from 20 to 48% - industrial enterprises, 5-9% - utilities. From the District of Buffalo, the water of Lake Erie is served along the Cana of Erie to the Gudson River Pool, to the city of New York. To replenish water resources of the Great Lakes, it is transferred to the lake to the top part of the runoff from the river system of Albany (Gudson Bay pool) through lakes Napigiga and Long Lake.

Great Lakes are connected to the Mississippi River Basin by the shipping channels, starting at the city of Chicago on Michigan Lake; With the Hudson River - a canal, originating from the city of Buffalo on Lake Erie. The River of St. Lawrence together with great lakes is the most important natural path that connects the inner parts of the United States and Canada with the Atlantic Ocean. The inner waterway of the Great Lakes is 1870 km due to the presence of gateway channels bypassing thresholds on the Saint Meriss River and Niagara Falls (Walland Channel). After the reconstruction completed in 1959, the reconstruction of the channels built into the crowded sections on the river of St. Lawrence, created the waterway from the Atlantic Ocean to the Great Lakes with a length of 3 thousand km and a depth of at least 8 m, accessible to major ships. Main ports - Duluth, Milwaukee, Chicago, Tolido, Cleveland, Erie, Buffalo (USA), Tander Bay, Hamilton, Toronto (Canada).

By the middle of the 20th century, a powerful anthropogenic effect led to strong pollution and eutrophication of the Great Lakes (especially in the bays). Due to the degradation of ichthyofauna from some areas of the coast Michigan, Guron, the uppermost disappeared previously numerous mink populations and otters. In the tissues of fish, high concentrations of DDT and mercury are noted. The least suffered from the anthropogenic impact of the lake top, while maintaining the oligotrophic status due to the larger size, the slowdown in the water supply and the low density of the catchment of the catchment (4.5 people / km 2). Water in it is most transparent (\u003e 10 m), it is characterized by the smallest content of phosphorus affordable for phytoplankton (<3 мг Р/м 3), низким показателем биомассы фитопланктона - хлорофилла «а» (<0,4 мг/м 3) и наименьшей первичной продукцией органических веществ (0,7 мг С/м 3 в час). Более низкое качество воды - в самом проточном озере Эри из-за меньших размеров и наибольшей нагрузки его эвтрофной экосистемы загрязняющими веществами сточных вод крупных городов. Экосистема Эри испытала сильнейшее эвтрофирование, но и ранее, чем в других озёрах, наступает её оздоровление благодаря запрету сброса в Великие озёра недостаточно очищенных сточных вод и наибольшей проточности. Водные массы Мичигана у южных берегов - мезотрофны, в центральной части - олиготрофны. Видовой состав фитопланктона Гурона характерен для олиготрофных озёр, но воды залива Сагино сильно эвтрофированы. Прибрежные воды Онтарио эвтрофны и мезотрофны. Будучи замыкающим, оно получает биогенные и токсичные вещества из остальных озёр (за последние годы скорость эвтрофирования заметно понизилась). В 1909 году правительства США и Канады подписали соглашения о совместном рациональном использовании водных ресурсов. В последней четверти 20 века работы по улучшению состояния Великих озёр активизировались. Для сохранности олиготрофии Мичигана обработанные сточные воды города Чикаго сбрасывают по судоходному каналу в бассейн реки Миссисипи.

Lite: World Water Balance and Water Resources of Earth. L., 1974; Biennial Report Under The Great Lakes Water Quality Agreement of 1978 ... Wash, A.O., 1982-2004-. Vol. 1-12-; Data Book of World Lake Environments. Otsu, 1988. Vol. 3: americas; Kondratyev K. Ya., Pozdnyakov D. V. Ecology of the Great North American lakes: problems, solutions, prospects // Water resources. 1993. T. 20. №1; Edelshtein K. K. Hydrology of continents. M., 2005.