In the language of the ancient Slavs, the name of the river was equivalent to the word “big”, which quite accurately characterizes the size of the largest river in our region. However, there are versions that the Slavs adopted this name of the river from the indigenous peoples of the region - the Finno-Ugric tribes. It would be surprising if the largest river in the region did not have its own name among the pre-Slavic population!

According to one version, the river was called that way: big, great, or “Issa” in Finnish. As if confirming this version, the left tributary of the Great River is called Issa. Scientists suggest that the indigenous peoples of the region considered the source of the Great Issa to be the beginning, and not the lakes Big and Small Elm, near which the Great actually originates.

The second version connects the name of the Velikaya River with the Finnish and Estonian word “välja” - “spacious, free”. In our region you can find several lakes with the name Velje. This word is not only consonant with the Russian name of the largest river in the region, but also quite close to it in meaning.

RIVERS OF MORNING AND LIES

The population of our region created a legend about these two rivers, called “Two Sisters”. According to legend, two sisters longed for their mother -Velikaya River. But along the way, one of the sisters committed treason, for which she was called Lie (i.e., “deceitful”). And the second river was called Utroya, which means “morning dawn”.

In fact, the name of the Lzha River has the root -lz-, which in Russian dialects means swamp.

As for the name of the Utroya River, there is still not a single plausible version of its origin. The least likely origin of the name is from two words at once: Russian “morning” and Finno-Ugric “oya” - “stream, ditch”.

Sometimes the Finno-Ugric word "udras" - "otter" - is used as the basis for the name. Then the name of the river can be translated as “otter stream.”

In Latvia, at its source, the river has the name Ritupe, translated from Latvian meaning “morning (eastern) river”. But this name may already be secondary, that is, translated from Russian, so it can hardly be considered proof of the correctness of the first version.

BLUE RIVER

The river is a left tributary of the Velikaya. At its source in Latvia, the river is called Zilupe, which translates as “blue river” (“zils” - blue, “upe” - river).

It would seem that this completely clarifies the origin of the name of the river in Russian. However, it is not.

There is a version that the name “Zilupe” appeared later than the Slavic one as a translation of the word “blue”. And before that, Latvians called the river Sinupe (“hay river”). The Russians remade this name in their own way - “Sinyukha”. And finally, there was a reverse translation into Latvian - Zilupe.

RIVER PLUSSA

The river flows into Lake Ilmen in the Novgorod region. It is likely that in the past it was called "Solona". Later, the sound “s” was replaced by “sh” as a result of a “lisp” (not distinguishing between these two sounds). The water in the river has a salty taste; along its banks you can find many salty springs and several salty lakes. In the Middle Ages, salt was transported along the river, a commodity in short supply at that time.

LAKE DVINYE

In the Pskov region there are two large lakes with that name. Both lakes are located on the Bezhanitsky Upland: in the Bezhanitsky and Loknyansky districts. The lakes were probably originally called "Ole". IN Ancient Rus' the word "ol" was used to describe any intoxicating drink other than grape wine. Even earlier this word was used to mean drinking water.

LAKE POLISTO AND RIVER POLISTO

Lake Polisto is located in the east of our region, almost on the border with the Novgorod region. The Polist River originates from the lake, flowing mainly through the territory of the neighboring region and connecting with the Lovatya River in its delta at the confluence with Lake Ilmen.

Both names are related in origin to the northern Russian words "olga, lyaga", meaning "swamp". All these words have a slightly modified root -lz- (“swamp”), like the names of many rivers in our region:

Lie, Lezica, Lizenka and others. Literally, the name “Polist” can be understood as “flowing through a swamp.” Indeed, the lake and the source of the river are the center of the largest swamp massif in the region.

LAKE LIVA

The lake is located in the southeastern part of the Sebezh region. The name of the lake was borrowed from the Finno-Ugric languages ​​(“liiva” - silt, mud). In Russian, the word has acquired a similar meaning: “lyva” means “swamp”. And now in some dialects a puddle or a swampy place in a swamp is called “liva”

Rivers and lakes are bodies of water that are most common on any continent. Despite this, many people confuse these two concepts and do not see much difference between them. Both bodies of water are the main sources of fresh water on earth, but there are many differences between them.

A river is a body of water that flows in a certain direction along a channel that it creates for itself. Rivers have natural origin. As a rule, most rivers originate in the mountains and flow to some large body of water, it can be a lake, ocean, sea. It is worth understanding that the river bed is created by itself and the direction of the flow is always unchanged.

A river can create branches and branches if the debris that floats along it creates a jam, but one way or another, the place where it flows remains unchanged, except when a person redirects the flow of water. Due to the large length of the river, its chemical composition can vary depending on the soil through which it flows. The river has its own regimes and they change depending on the time of year, but at the same time remain unchanged over the centuries. These include floods, floods and other phenomena.

The river is fed by several sources at once. These are glaciers that melt high in the mountains, precipitation, underground sources. It is wrong to think that a river is a channel along which water flows. The concept of a river includes the term river basin, which refers to all the branches and small rivers that flow into the main one. The area where these branches and incoming rivers are located is called a river basin. If a river is divided into several sections by mountains, then such places are called a watershed. The water in the river always has a current and this is one of the important features of the river. There are several large rivers in the world, as well as many small ones.

The most hardworking is Colorado River, since during its existence it dug the entire Grand Canyon. The phenomenon when a river creates a channel for itself is called erosion. The Yellow River is considered the strongest river, because it carries a lot of garbage and forest, which it pulls out of the eroded land. For this reason it is called the yellow river. The Danube, Nile and Mississippi were considered the most creative. Due to the large amount of garbage, such congestions have repeatedly formed in them that the river had to look for independent bypass routes and create a new delta for itself.

Lake

A lake is water that is in closed recess. In other words, any large depression that fills with water over time can be considered a lake. For a long time it was believed that a lake is a body of water into which water comes but does not leave. This is not entirely true, since there is even a division into sewage lakes and non-waste lakes. The former give rise to rivers, the latter do not. Famous sewage lakes include Baikal, and not the Caspian Sea, lake Chad And .

A lake can be filled with salt or fresh water, although unique occurrences occur where the lake is half salt and half fresh. Such an example is Balkhash. One of the sides is fresh due to three rivers flowing into it at once. In my own way chemical composition The water in the lake is almost always homogeneous, since the depression in which it is located has the same soil everywhere. Lakes are divided according to their method of origin into volcanic (in the crater of a volcano), tectonic, glacial and others. As a rule, lakes are also distinguished by the fact that the water in them is stagnant and it is fed by underground springs, flowing rivers, and precipitation.

The largest lake is Caspian Sea, salty – Dead Sea, and deep - Baikal. The lake has a stable temperature depending on the time of year. Due to the fact that the lakes are located in one place and are practically unchanged, there are several unique lakes in the world. The boiling lake is located on the island Domika. Its temperature reaches 80-100 degrees. Lagoon - Colorado has a dirty blood-red hue due to the large amount of algae. Plitvice lakes are a group of lakes that are located at different heights and flow into each other. The Aral Sea is currently completely dry.

A unique lake is located in the USA Crater Lake. It appeared about 7700 years ago. Despite the absence of any sources of nutrition, it itself is filled with sediment and is one of the cleanest and most transparent in the world.

Differences between a lake and a river

The main differences between a lake and a river are the following:

1. The chemical composition is uniform in the lake and different near the river.
2. The presence of a constant flow.
3. Rivers are only fresh, lakes can be salty or fresh.
4. Length.
5. Structure and behavior over time.
6. Temperature difference. The lake is quite stable; the river may vary depending on where it flows.
7. Lakes are fed by rivers and are very rarely fed by them.
8. The lakes do not create their own landscape, but are located in an already existing depression. Rivers can change their course, shape and depth over time.
9. Method of origin. Lakes can be of artificial origin, rivers are always the result of the activity of nature. The river is always the beginning and the end. A lake is a “container” of water that does not change over time, without beginning or end.
10. The lake is not part of the world ocean, since it may not have any communication routes with it.

Despite the difference, rivers and lakes are very important for humans, since they are the main sources of fresh water. From time immemorial, people settled near these reservoirs, since on the one hand a river or lake could provide not only drink, but also water, but on the other hand, it was not very easy to get to the settlement from the water.

Several years ago, scientists around the world began to say that many reservoirs on our planet were losing volumes of water. Science has found its explanation for this - the situation is directly linked to global climate change, and therefore identified a serious problem for humanity. It lies in the fact that in a few decades more and more countries on Earth will experience a shortage of not only drinking water.

A shortage of life-giving moisture will become an obstacle to unlimited shipping and, in general, the situation will have an extremely negative impact on the ecology of many territories. Journalists from the publication “Ecology of Regions” decided to analyze the theoretical statements of scientists, using open sources, the media, forums and social media, as well as the opinions of experts who agreed to assess what was happening. And it is worth noting that the problem really exists and it should have been solved yesterday. Today, the only area on the planet where water levels are constantly rising is the Arctic. The process of snow melting, which has accelerated in last years, has led to the fact that scientists are forced to look not for the reasons for what is happening, but for opportunities to stop the process. In general, every year on Earth there are fewer and fewer sources of fresh water - large and small rivers are drying up, lakes are drying up, and the volume of water in the seas is decreasing. According to American scientists, over nine hundred thousand small rivers have dried up since 2004. It’s no better in Russia: each region is ready to provide its own story about how they become shallow big rivers and the little ones disappear.

Irkutsk region, Russia. Low water levels affect the condition of reservoirs. Scientists note that there is less water in the Angara and Bratsk reservoirs; Baikal, where the water level is below a critical level, is of particular concern. Ecologist Ivan Smolensky considers uncontrolled cutting down of green spaces in the region to be one of the main problems that influenced the development of the situation. “The results of many years of research show how cutting down trees affects the condition of reservoirs and their filling. In the Irkutsk region uncontrolled logging forests has been going on for decades. The sad consequence of this is a sharp decline water levels in reservoirs, drying up of small rivers. And the day will come when there will be no more trees or water left in the Irkutsk region.”

Samara region, Russia. About the rapid shallowing of the main tributary of the Volga - the Samara River. In 2013, it was officially announced that Samara was among the top ten cities in the country with an unfavorable environmental background. Naturally, such results were announced not only after studying the state of atmospheric air and soil in the constituent entities of the federation, but also the state of water bodies. So, in Samara, scientists and environmentalists stated that small rivers are rapidly dying every year, the areas where they ran are becoming swamped, and the chairman of the Samara Regional Green League, Sergei Simak, stated the need to develop and implement a regional comprehensive program to save the region’s reservoirs . The main reason for what is happening in the Samara region was called active human activity. It is he who pollutes rivers with industrial waste, puts coastal areas in disarray and does not care about protection environment. Today, shipping in the Samara region is under threat, and representatives of shipping companies recall the times when the Volga was a deep river and there was no reason to think that the river would begin to shallow and stop river ships.

Voronezh region, Russia. In 2015, environmentalists in the Voronezh region officially announced that over thirty rivers had disappeared in the region. In this subject of the federation, the vast majority of small rivers, the condition of which has deteriorated sharply over recent decades - they have become shallow and do not receive enough water to recover. In 2010, the regional government approved a concept for saving small rivers; within its framework, funds are annually allocated for surveying and clearing river beds. But overall the situation remains critical.

Tula region, Russia. Local ecologists report low water levels in the region's reservoirs - they occur in the summer, and even periods of short rainfall do not fill the reservoirs with the required volume of water. The region has become very shallow in recent years large rivers, and several small rivers dried up. The water resources of small rivers currently amount to 1.3 km3 of water at 75 percent supply. Depending on the natural conditions for individual rivers the distribution of annual runoff has different specific features. Officials see improvement in the situation in carrying out measures to save small rivers Tula region, but often the implementation of planned work is limited by a lack of funding.

Rostov region, Russia. Last year scientists Rostov region announced an imminent environmental disaster - the Don River, one of the main arteries not only in this region, but throughout the entire Southern Federal District, is becoming shallow. As a consequence - shallowing of the Volga, a threat to the existence of the shipping company, and the extinction of many types of aquatic biological resources. A clear shallowing of the Don has been observed over the past ten years. Candidate biological sciences Oleg Stepanyan believes that one of the reasons is the increase in dry years in the country. Low water levels in the Don are observed not only in summer, but also at other times of the year. The marginal sections of the river delta are observed to die off. And in parallel with these, catastrophic surges of salt water from the Sea of ​​Azov are observed. Low water supply has already become one of the reasons for the poor quality of drinking water. Scientists believe that the basic water supply was disrupted due to environmental stresses following the massive abandonment of coal mines in the region. The region's water supply is based on the use of surface and groundwater, which is distributed unevenly. Ecologists make the most unfavorable forecasts for the future.

And, perhaps, the Volga found itself in the most critical situation. Its shallowing is observed in many regions of Russia. And if ten years ago scientists spoke about the need to save the river, today environmentalists say it is impossible to stop the process of destruction of water resources, which man began not yesterday, but many years ago, by thoughtlessly using Natural resources in their own interests, without thinking of restoring nature after taking advantage of its gifts.

Lakes are bodies of water with standing or slowly flowing water of natural origin. They form in depressions in the relief, and the reasons for their occurrence can be different. It is worth considering the main types of lakes, based on the characteristics of their appearance, in order to understand the classification of these reservoirs and understand how they are formed as a whole. Any water tends to lowlands, various depressions. And lakes also arise in natural lowlands, even if such folds of relief arise above the level of the world's oceans.

The reasons and algorithms for the formation of lakes are not uniform; it is worth considering several mechanisms to understand the details of this issue.

Tectonic, volcanic processes

The largest and deepest lakes on Earth were formed due to tectonic processes, in cracks in the earth's crust or its troughs. Thus, Lake Onega is located in a trough of tectonic origin, and Lake Baikal is located in a deep crack. Moreover, this crack is gradually spreading, threatening to split Eurasia into two parts, and therefore Baikal is steadily expanding and deepening. One day it will be filled with ocean waters and it will become a sea. Volcanic lakes have slightly different specifics. They can be seen in regions where there are volcanoes - in Russia there is such an area in Kamchatka. If lava from a volcano blocks the path of a river, a volcanic lake appears. Water can also accumulate in the crater of a dormant volcano. Such a lake will exist until a new eruption begins.

Glacial lakes and reservoirs in ravines

The northern regions are rich in lakes of glacial origin. The basins of these reservoirs appeared due to the movement of glacial masses that pushed through the upper layers of the earth. Also, these lakes arise from moraines - mud masses left by melting glaciers in the mountains. When moving, they can block and dam the river, forming a lake. If the soil is rich in rocks that are easily washed away by water, aboveground or underground lakes may also appear in it. Water can wash away gypsum, dolomite, limestone, and occupy this space with its own mass. This is how karst caves are formed - they are often filled groundwater, creating a whole network of lakes underground.

Interesting processes can occur in permafrost areas - here, when thawing in the warm summer period, the soil can sag, forming a place for a shallow lake. Lakes can also appear when the flow of water in a river slows down - usually this happens when the riverbed is strongly curved and tends to straighten out. A section of the former loop can become a lake or swamp; such objects are called an oxbow lake.

A spit can also separate a lake from the main body of water, for example, from the sea. A sand spit can separate a shallow area from the sea, and it will be called a lagoon. With complete separation, this same formation will be called an estuary.

There are many options for the formation of lakes. And these reservoirs themselves can be either less or more durable. Some of them exist only for a few days, while others live for thousands of years and are only expanding. But in any case, each lake is individual; these are priceless natural formations that must be protected. Small lakes are sources of fresh water, of which there is not much left on the planet. And large ones, such as Baikal, have a rich natural world, often unique, worth saving for our children.

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According to Socrates, the exact word reflects reality. So the common name of these five majestic natural reservoirs confirms this truth. They are given a name - Great Lakes. They, connecting with each other, formed a unique water system on the border of southern Canada and the northeastern United States.

These Great Lakes of North America have a total water surface area of ​​more than 240,000 square kilometers and a fresh water supply that accounts for 1/5 (21%) of the world's total.

Origin story

During the formation of the North American continent, tectonic processes took place that shaped the landscape of the area with highlands and lowlands.

Later, about a million years ago, the territory of the modern northern United States and Canada was covered by an ice sheet, which modern scientists named Laurentite (after the St. Lawrence River). Its height, according to various estimates, at its peak reached one and a half to two kilometers. During the time it was formed and melted, it significantly influenced the future landscape of the area.

12,000 years ago the glacier retreated towards the North Pole. Natural pits on the land surface were filled with melted fresh water. This created the largest lake system in the world. It includes five main lakes, interconnected by streams, rivers, channels and straits, and many medium-sized and smaller reservoirs and marsh formations.

The system and individual islands received their name when European pioneers explored the central and northeastern parts of the continent. This happened in the 17th-18th centuries.

List describing the great lakes of North America

Five pearls from the necklace of the world's most beautiful and largest natural fresh water reservoirs are located on the northeastern border of the United States and Canada. Regarding their location above sea level, they are divided into upper (Superior - the largest, Huron, Michigan) and lower (Erie and Ontario - the smallest of the five). In addition to these large ones, the system contains a number of medium-sized reservoirs.

These primarily include:

• St Mary's;
• St. Clair;
• Nipigon.

The water basin includes more than a thousand small lakes.

The biggest

Of course, it is the large lakes that attract the greatest interest.

Upper

It got its name due to the fact that it is located at an altitude of 186 meters above the Atlantic Ocean. The top one is the largest and coldest.

The volume of fresh water exceeds 12 thousand km³. In the north it washes the coast of the Canadian province of Ontario, on the other sides - the coast of the American states of Minnesota, Wisconsin, and Michigan. The northern coast is mostly mountainous.

The water of the reservoir, even in summer, does not warm up above 5º C. But thanks to this fact, it is the cleanest of all the reservoirs in the basin. In winter, only the coastline freezes. The rest of the surface of the reservoir is exposed to seasonal northwest winds, which cause constantly raging storms. Sometimes waves reach a height of 10-12 meters.

The St. Marys River flowing from it flows into the lower cascade of Lake Huron.

Huron

Its wide spatial location allowed it to have a wide variety of natural zones along its coastline.

Its waters also wash the coasts of two countries. The same Canadian province and two states: Illinois and Michigan. On the eastern part of the lake there is the largest lake island in the world - Manitoulin.

Michigan

The name comes from the Indian word Mishegani, which means Big Water. Wide Michigan Strait like brother to brother - hand in hand - unites with Huron . This is the only lake of the five located entirely in the United States.

Their shared ecosystem is in constant interaction and exchange. Therefore, their average annual water temperatures and climate are approximately the same. The total supply of drinking water in the two reservoirs is 8.4 thousand km ³.

Lake Michigan has an elongated shape and 2.5 thousand kilometers of coastline. The two largest port cities of the Great Lakes—Milwaukee and Chicago—are located on the shore, each a hundred kilometers apart.

Erie

Further down the cascade is Lake Erie. Its area is 25,600 km². Its natural feature among the brothers is expressed in the smallest depth - it is just over 60 meters. Accordingly, it warms up well, which makes it popular as a resort place.

The plateau slopes towards the ocean, and the water flowing from Erie many millennia ago has found its way to the east. Its flow turned into a short river, but famous for its unique waterfall - the Niagara River. After 56 kilometers of travel, it flows into the smallest of the Great Lakes - Ontario.

Ontario

The name means "Lake of Shining Waters" in the Huron language.

The location and the presence of a warmer climate have turned this lake into a tourist paradise. It is found in a large number of fish of different breeds.

Around:

• agriculture is widely developed;
• Selected grape varieties are grown;
• elite varieties of wines are produced.

St. Lawrence River, in flowing from Ontario, is the only natural spillway of the system into the Atlantic.

The smallest

There are thousands of small lakes around the Great Lakes. Most of them are located in Canada. They are evenly dispersed between Lake Superior, Lake Huron, and the St. Lawrence River.

Of these, the following are noted:

• Barque;
• Scugog;
• Dumoine;
• Kuerk.

Some of them are so small that it is difficult to find these lakes on the map.

Meaning

The existence of such a water system in the region is of enormous importance. Its presence is a fundamental factor in active life in the northeastern United States and southern Canada. His main reason is the total supply of drinking water.

Fresh water from this system supplies a population of 40 million people. A unique ecosystem has developed around it, which not only accepts the existing climate and weather, but itself influences and shapes them. The basin of the entire water area contains 25% of Canadian agricultural production and 7% of the United States. Electricity generation by the GRES network along the waterway of the entire system is 50 billion kilowatts per year.

Shipping

The lakes have been used as a transport route since their discovery. Since ancient times, the Indians have been actively moving to these regions on their famous pirogues and canoes. Considering the inaccessibility of many areas in the vicinity of the lakes, passenger, trade and cargo shipping began to actively develop in the second half of the 17th century.

Currently, a variety of industrial and agricultural goods and raw materials are transported along the 3,000-kilometer-long waterway, reconstructed in 1959. There are about 65 ports on the Great Lakes, 15 of which are international.

Tourism

The natural diversity of the entire basin and the surrounding lakes have created excellent conditions for the development of almost all types of tourism.

The main ones are:

1. Fishing. Individual tours are especially popular. All fishermen note the richness and diversity of local fish species. The main ones are perch, coho salmon, smelt, chinook salmon, char, trout, whitefish, pike, trout, salmon, crappie and about 120 other species.
2. Water tourism on small rowing boats(canoes, kayaks, kayaks). There are many routes with equipped places for rest and overnight stay. Those who wish can go to completely wild corners of the lakes. Thanks to the presence of channels, canals and rivers, travelers can get from anywhere to anywhere in the Great Lakes basin.
3. Beach holidays and spa treatments. Mostly people go to Ontario and Erie for these types of recreation.

70 million people, according to official statistics, annually visit the majestic lakes for tourism purposes.

The uniqueness and diversity of the local ecosystem: sandy beaches and rocks, wild steep banks and coastal dunes, deciduous relict forests and prairies, pine and cedar groves - this is far from full list represented natural forms of the region.

Uniqueness

The climate in the water area of ​​the system is humid, moderate continental. The weather changes frequently, and various cyclones have a significant impact. Average air temperatures in January range from –8° C in the northern part up to –3° C at southern shores. Average in summer - 18-21° C.

The water of the lakes is one of the cleanest among all lakes in the world. They have low mineralization (from 0.06 to 0.13 g/l). This is due to the implementation of large preventive and cleanup measures in recent decades (before that the situation was much worse). Its average transparency (visibility in depth) is 15 meters. Slightly cloudy in windy weather.

The system is replenished with water through:

• waste water;
• precipitation;
• underwater sources.

Drinking water from the lakes is consumed by 40 million people. Thirty - in the USA and Canada; and is also exported to 50 countries. The total water consumption is more than 20 km³/year. Most pure water in northern Lake Superior, least in southern Erie.

The table shows the main characteristics.

Ecological problems

The presence of large industrialized cities and entire conglomerations on the coast at one time led to severe pollution of water resources. Discharges of waste industrial water and waste from factories in the 18th-19th centuries did not have any treatment. Only in the 20th century did they begin to seriously address environmental issues in the system’s waters.

By the 1970s, the issue became so pressing that the governments of two countries, the United States and Canada, began to discuss it at the state level. Thus, in 1972, they signed the “Great Lakes Water Quality Agreement.” These measures have received the widest response from all stakeholders and the public. We began to carry out systematic work aimed at improving the environmental situation in the region. Many have been created national reserves and parks. This in turn provides more opportunities to preserve the pristine nature of this area.

By the beginning of the 21st century, scientists carried out a number of observational activities that confirmed the positive results of timely measures taken. The water quality has improved significantly.

There are a great many of them in the history of the discovery, settlement and exploration of North America.

Here are just a few of them:

1. The discovery of unique lakes was accompanied by the following factor: the French pioneers, referring to the stories of local Indians from the outskirts of Quebec, went to look not for lakes, but for Mishigani (in Indian language - “big water”). Which, according to them, was located to the West of the headwaters of the St. Lawrence River. The French “forest tramps” (as their contemporaries called them) assumed that this water would Pacific Ocean, and through it a direct road to India will open for them.
2. For a long time, scientists could not give a definite answer to the cause of the origin of the lakes. Initially, options for volcanic processes or water erosion of the land surface as factors in the formation of lake basins were considered. But only towards the end of the 20th century it was absolutely clear that the large lake system was formed as a result of the “work” of the Laurentian glacier. This went on for a million years. And only by the 12th century BC did it melt and retreat so much that the depressions it made could be filled with fresh water.
3. The lake pits were formed due to primary tectonic processes and prolonged exposure to the glacier. It created pressure from above with huge masses of ice (their height reached 1.5-2 km) and interspersed with fragments of soil, rocks, pumice, etc. As it moved along the surface, the future bottom of the lake system was “polished.” At the same time, under the weight of the glacier, the surface of the earth was pressed deeper. Therefore, under the influence of inertial forces, the reverse process is now occurring - the raising of the concave surface (bottom of lakes) at a speed of 2.5 mm per year.
4. The location of Niagara Falls, which is known and accessible for inspection now, was much further downstream. Over several thousand years, it “rose” significantly upward (approximately 10-11 kilometers). This happened due to gradual hydroerosion of the riverbed soil. The water destroys the slopes of the rocks bit by bit, the microparticles are washed downstream, and the ledge of the waterfall retreats back. Now this process is significantly “slowed down” due to the work of bypass channels.
5. Lake Superior, being the largest freshwater lake, is second in size to the salty Caspian. Although it is written as “Caspian Sea” on maps, it is actually a lake. Its area is more than 370,000 km 2.
6. The lake system of North America is unique and diverse. In addition to the presence of huge bodies of water and their combinations, its territory also contains the smallest lake in the world. It is called Sarasota, and it is located in the southern state of Florida. Its diameter is only 120-130 meters.

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