What is river regime? What does it depend on? Name the main types of water regime of rivers in Russia and your area. Classifications of river water regime

A river is a water stream that flows in a depression in the relief, called a channel, and is fed by the flow of water. The beginning of this stream is called the source, and the place where the sea or other stream flows into the lake is called the mouth. Along its entire length from source to mouth, other streams, called tributaries, may flow into it. The number of tributaries depends on the climate of the area and the amount of precipitation. The sources are often springs, swamps, lakes or glaciers. The area from which water collects is called a basin. The boundary between basins is a watershed. River classification carried out according to several criteria: the nature of the course, type of nutrition and regimen.

by the nature of the flow

On this basis river classification allows us to distinguish the following types: plain, mountain and mixed. Their differences directly depend on the terrain through which they flow.

Plain water streams have slow current, because their origins are not located high altitude relative to the mouth. They flow through the territory with a slight slope. They are characterized by wide valleys and sloping slopes. This species includes the Volga, Nile, Dnieper, Amazon, Congo and many others.

Unlike lowland rivers, mountain rivers have a higher flow speed. Their sources are located at a high altitude, high in the mountains, and the slope of the area where they flow is very high. Their valleys are narrow and rocky, and their slopes are steep. They often form waterfalls. The highest of them is Angel Falls in South America, whose height is 1054 m.

Mixed ones originate high in the mountains, but then reach the plain. Therefore, in the upper reaches they can be classified as mountainous, and in the middle and lower reaches - as flat. When they enter the plain, their appearance changes dramatically, they slow down, and the channel widens. This is what the Terek looks like in its various sections.

Volga river

Differences by food type

Rivers are fed by collecting water from their basins. They differ depending on the type of territory where they flow and seasonal availability precipitation. There are rain, lake, swamp, glacial, karst and mixed.

Rain feeding is usually observed in areas equatorial climate, where there is no seasonality, and it rains constantly. This type includes the Amazon and Congo.

Lake replenishment is typical for rivers flowing from lakes. These include Angara, Volkhov, Neva, Biya and some others. There is also swamp feeding in particularly wet areas. Usually the terrain here is flat, and the rivers flow very slowly, carrying swamp waters. This type is typical for all Western Siberia.

Glacial feeding ensures the melting of glaciers. This is how the Amu Darya and the Amazon tributaries, which originate high in the Andes, obtain water. Also, sometimes mountain rivers are characterized by a karst type, when they receive water from underground karst depressions. The most common type of diet is mixed.

Amur river

by mode

River regime - differences in its behavior by season. It is divided into high water, high water and low water. Flood is a significant increase in the water level and water content of a stream. Flood is a short-term rise in level as a result of heavy rainfall. Low water period low level water. The mode can be: equatorial, tropical, temperate, and arctic.

The equatorial regime is characterized by the absence of any seasonal differences. For the tropical, floods during the rainy season and drying out or shallowing during the dry season are common. Moderate water is characterized by significant fluctuations in level: floods in spring, and low water in winter and summer. The Arctic is characterized by snow feeding, freezing for a long period, and very short runoff.

Carrying out a clear river classifications of a given area allows us to determine their characteristics, which is important for the possibility of their competent use in economic activity. Thus, hydroelectric power stations are built on fast-flowing rivers, and in arid areas the water is used to irrigate fields.

Russia is a country of abundance water resources. About 2.8 million rivers and streams flow through its territory, the total length of which is 12.4 million kilometers.


Each of them is unique in its own way, having its own water composition, channel topography, flow speed and other features. When subjugating nature and improving his habitat, a person is obliged to take into account the characteristics of each element of the natural landscape.

This is most true for our rivers, which supply cities and rural areas with water. Did you know that every river, even the smallest one, has native mode, to which her existence is subject?

What is river regime?

Many river parameters change depending on seasonal changes climate. In the spring, when the snow accumulated over the winter melts, turning into water, the rivers increase in volume and change their chemical composition, and often the current speed.

In the summer, when scorching heat reigns and the water in the riverbed is actively evaporating, the river becomes shallow, and small algae can actively multiply in its waters, coloring it green color.

In winter, the riverbed is covered with ice, and aquatic life settles for the winter, burrowing into the river silt. All these fluctuations are called the river regime. In the language of science, the regime of each river is cyclical changes in the temperature of its water, level, flow speed, water composition and many other parameters.


The river regime is not considered in itself, but in a complex that includes geographical, physical and climatic factors, most characteristic of this area. Greatest influence The regime is affected by temperature fluctuations, the amount and time distribution of precipitation, the level of evaporation and water infiltration through the rocks that make up the channel.

Lowland areas are more characterized by zonal changes in natural factors, in accordance with which the regime and water balance of rivers changes. Mountain rivers are mainly subject to altitudinal zone, according to which the parameters of their mode change.

River regime phases

Hydrologists distinguish three main phases that make up the regime of any river: low water, high water and floods.

1. – a rise in level and an increase in water flow associated with the entry of large amounts of melt or rainwater and repeated annually during the same season. During floods, the river usually overflows its banks and floods the floodplain. The timing of the flood depends on local geographic and climatic conditions.

2. – a rise in water level, which is caused by abundant heavy rains or thaws. Unlike high water, floods are characterized by a rapid but short rise in level. In Russia, floods often occur at the end of summer or autumn, when there is a period of heavy rainfall.


3. – a period of low water content, during which the river is recharged mainly from underground sources. In our climate, hydrologists distinguish between summer and winter low water.

What does the river regime depend on?

The river regime depends on many factors, the most significant of which are:

— geographical position;

— water nutrition, i.e. sources that replenish the water level in the river (precipitation, groundwater, glaciers, lakes);

— climatic features– dry or humid climate, the dynamics of seasonal temperature fluctuations, the strength and direction of the wind, which influence the water level;

— terrain – flat or mountainous;

- rocks that make up the channel - sand, clay, hard rocks;

- flora and fauna of the river - vegetation and animals can affect the composition of the water and the speed of its flow;

- anthropogenic impact - the presence of cities and enterprises on the banks of the river that discharge wastewater into it and take water for their consumption.

These are the main factors whose influence on the river regime is most pronounced. However, there are many less noticeable factors, the influence of which can become decisive under certain conditions.


The river ecosystem is fragile, and any ill-considered impact can unbalance the river regime, causing unfavorable changes in it.

A river is a natural permanent water stream (watercourse) of significant size with a natural flow along the channel (the natural depression it has created) from the source down to the mouth and fed by surface and underground runoff from its basin.

The rivers are integral part hydrological cycle. Water in the river is usually collected from surface runoff resulting from atmospheric precipitation With a certain area limited by a watershed (river basin), as well as from other sources, such as reserves groundwater, moisture stored in natural ice (during the melting of glaciers) and snow cover.

In places of natural or artificial obstacles to the flow of a river, reservoirs (flowing lakes or artificial seas) appear. Limnology (Greek λίμνε - lake, λόγος - study) or lake science is a branch of hydrology, the science of the physical, chemical and biological aspects of lakes and other fresh water bodies, including reservoirs. In turn, rivers are the subject of one of the largest sections of land hydrology - river hydrology or potamology (from ancient Greek ποταμός - river, λόγος - study - literally the science of rivers), which studies the structure of river networks, river flow, morphometry of rivers swimming pools and so on. As a rule, rivers make their way and flow through zones of least stress and resistance - along tectonic faults.

Energy has long been fast rivers and waterfalls are widely used in human economic activities as a source of renewable energy to operate water mills and hydroelectric power turbines.

General information

In each river, a distinction is made between its place of origin - the source and the place (section) where it flows into the sea, lake or confluence with another river - the mouth.

Rivers that directly flow into oceans, seas, lakes or are lost in sands and swamps are called main; flowing into main rivers - tributaries.

The main river with all its tributaries forms a river system characterized by density.

The land surface from which a river system collects its waters is called a catchment, or drainage area. The drainage area together with top layers The earth's crust, which includes a given river system and is separated from other river systems by watersheds, is called a river basin.

Rivers usually flow in elongated low forms of relief - valleys, the lowest part of which is called a channel, and the part of the valley bottom flooded with high river waters is called a floodplain, or floodplain terrace.

The channels alternate between deeper places - reaches and shallow areas - rifts. The line of the greatest depths of the channel is called the thalweg, close to which the ship passage or fairway usually passes; the line of highest flow velocities is called the core.

The boundary of a river's watercourse is the bank; depending on its location along the stream relative to the center line of the watercourse's bed, the right and left banks of the watercourse are distinguished.

The difference in height between the source and the mouth of a river is called the fall of the river; The ratio of the fall of a river or its individual sections to their length is called the slope of the river (section) and is expressed as a percentage (%) or in ppm (‰).

Rivers are distributed extremely unevenly across the surface of the globe. On each continent, it is possible to outline the main watersheds - the boundaries of the areas of runoff entering various oceans. The main watershed of the Earth divides the surface of the continents into 2 main basins: the Atlantic-Arctic (the flow from the area of ​​which flows into the Atlantic and Arctic oceans) and the Pacific (the flow into the Pacific and Indian oceans). The volume of runoff from the area of ​​the first of these basins is significantly greater than from the area of ​​the second.

The density of the river network and the direction of flow depend on the complex of modern natural conditions, but often, to one degree or another, retain the features of previous geological eras. The river network reaches its greatest density in equatorial belt where they flow greatest rivers world - Amazon, Congo; in tropical and temperate zones it is also high, especially in mountainous regions (Alps, Caucasus, Rocky Mountains, and so on). In desert areas, sporadically flowing rivers are common, occasionally turning into powerful streams(rivers of lowland Kazakhstan, oueds of the Sahara, Creek (drying up river) and Australia and others).

Classification

Classification of rivers by size

• Large rivers are lowland rivers with a basin area of ​​more than 50,000 km2, as well as predominantly mountain rivers with a drainage area of ​​more than 30,000 km2. As a rule, their basins are located in several geographical zones, and the hydrological regime is not typical for each river geographical area separately.
• Middle rivers are lowland rivers, the basins of which are located in the same hydrographic zone, having an area from 2000 to 50,000 km2, the hydrological regime of which is characteristic of rivers in this zone.
• Small rivers are rivers whose basins are located in the same hydrographic zone, have an area of ​​no more than 2000 km2 and whose hydrological regime, under the influence of local factors, may not be typical for rivers in this zone.

Topographic classification

Depending on the topography of the area within which the rivers flow, they are divided into mountainous and flat. Many rivers alternate between mountainous and flat areas.

• Mountain rivers, as a rule, are distinguished by large slopes, rapid currents, and flow in narrow valleys; erosion processes predominate.
• Lowland rivers are characterized by the presence of channel meanders, or meanders, formed as a result of channel processes. On lowland rivers there are alternating areas of channel erosion and accumulation of sediment on it, as a result of which muddy bars and riffles are formed, and deltas are formed at the mouths. Sometimes branches that branch off from a river merge with another river.

Hydrobiological classification

Classification according to the possibility of water sports

According to the International River Difficulty Scale, there are six levels of difficulty.

Classification by tributary network configuration

There are 12 classes of rivers based on the nature of the network of tributaries, determined by the Strahler Number. The headwaters of the rivers according to this system belong to the first class, and the Amazon River to the twelfth.

Use of rivers

Since ancient times, rivers have been used as a source fresh water, for obtaining food (fishing), for transport purposes, as a protective measure, demarcation of territories, as a source of inexhaustible (renewable energy (rotation of machines (for example, a water mill) or hydroelectric turbines), for bathing, irrigation of agricultural land and as a means of disposal from waste.

Rivers have been used for navigation purposes for thousands of years. The earliest evidence of river navigation dates back to the Indus Valley Civilization, which existed in the northwest of modern Pakistan around 3300 BC. The use of river navigation in human economic activities provides cheap (water) transport, and is still widely used on the world's largest rivers, such as the Amazon, Indus, Ganges, Nile and Mississippi (river). The amount of harmful emissions produced by river vessels throughout the world is not clearly regulated or regulated, which contributes to the constant release of large amounts of greenhouse gases into the Earth's atmosphere, as well as an increase in the incidence of malignant neoplasms among the local population as a result of the constant inhalation of harmful particles emitted into the air by water transport .

The rivers are playing important role in determining political borders and protecting the country from the invasion of external enemies. For example, the Danube was part of the ancient border of the Roman Empire, and today the river forms much of the border between Bulgaria and Romania. The Mississippi in North America and the Rhine in Europe are the main borders dividing the east and west of countries located on their respective continents. In southern Africa, the Orange and Limpopo rivers form the boundaries between provinces and countries along their routes.

Flood

A flood (or flood) is part of the natural cycle of a river - one of the phases of the river’s water regime, repeating annually in the same season of the year - a relatively long and significant increase in the river’s water content, causing its level to rise. Usually accompanied by the release of water from the low-water channel and flooding of the floodplain.

Flood is a phase of the water regime of a river - a relatively short-term and non-periodic rise in the water level in the river, caused by increased melting of snow, glaciers or an abundance of rain. Unlike a flood, a flood does not recur periodically and can occur at any time of the year. Significant flooding may cause flooding. As the flood moves along the river, a flood wave is formed.

Flood - flooding of an area as a result of rising water levels in rivers, lakes, seas due to rain, rapid snow melting, wind surge of water to the coast and other reasons, which damages people's health and even leads to their death, and also causes material damage . Wind surges of water in sea estuaries and on windy areas of the coast of seas, large lakes, and reservoirs. Possible at any time of the year. They are characterized by a lack of periodicity and a significant rise in water levels.

Much of the process of erosion of river beds and deposition of eroded rocks on the corresponding floodplains occurs during floods. In many developed areas of the world economic activity humans have changed the shape of river beds, influencing the magnitude (intensity) and frequency of floods. Examples of human impacts on the natural state of rivers include the construction (creation) of dams, straightening of riverbeds (construction of canals), and drainage of natural wetlands. In most cases, human mismanagement in floodplains leads to a sharp increase in the risk of floods:

• artificially straightening a river bed allows water to flow faster downstream, increasing the risk of flooding in areas downstream;
• changing the nature of the river floodplain (straightening) removes natural flood control reservoirs, thereby increasing the risk of floods in the lower reaches of rivers;
• creating an artificial embankment or dam can only protect the area downstream of the river (behind the dam), and not those areas that are located upstream;
• The presence of a dam, as well as straightening and strengthening of banks (for example, the creation of embankments, etc.) can also increase the risk of flooding in areas located upstream of the river. As a result, there is a difficulty in outflow and an increase in pressure exerted on the downward flow, associated with an obstacle to the normal outflow of water due to the narrowness of the channel enclosed between the reinforced banks.

underground river

Most, but not all rivers flow on the surface of the Earth. Underground rivers flow underground in caves. Rivers of this kind are often found in regions with limestone (karst) deposits in geological formations. In addition, there are caves formed in the body of glaciers by melt water. Such caves are found on many glaciers. Melted glacial waters are absorbed by the body of the glacier along large cracks or at the intersection of cracks, forming passages that are sometimes passable for humans. The length of such caves can be several hundred meters, depth - up to 100 m or more. In 1993, a giant glacial well “Isortog” with a depth of 173 m was discovered and explored in Greenland; the influx of water into it in summer was 30 m3 or more. Due to the presence of a “roof” formed from geological rocks impenetrable to water (or ice) and high pressure directed towards the overlying glacier masses, a so-called topographic gradient is created - such streams can even flow uphill. Another type of glacial caves are caves formed in a glacier at the point of release of intraglacial and subglacial waters at the edge of the glaciers. Meltwater in such caves can flow both along the glacier bed and over glacial ice.

Water is usually found in many caves, and karst caves owe their origin to it. In caves you can find condensation films, drops, streams and rivers, lakes and waterfalls. Siphons in caves significantly complicate passage and require special equipment and special training. Underwater caves are often found. In the entrance areas of caves, water is often present in a frozen state, in the form of ice deposits, often very significant and perennial.

Puerto Princesa Underground River is an underground river near the Philippine city of Puerto Princesa, on the island of Palawan (Philippines). This river, about 8 km long, flows underground, in a cave, in the direction South China Sea. Created in the area where it is located National Park underground river of the city of Puerto Princesa (Puerto Princesa Subterranean River National Park) - a nature reserve located 50 km from the city. The park is located in the St. Paul Mountain Range in the northern part of the island and is bounded by St. Paul Bay and the Babuyan River. A similar river is known on the Yucatan Peninsula in Mexico, but this one is recognized as the largest. Both underground rivers owe their origin to the karst topography. The water in these rivers changed direction, finding its way down, thanks to the dissolution of carbonate rocks and the formation of a vast underground river system.

The Hamza River (port. Rio Hamza) is the unofficial name of the underground flow under the Amazon. The opening of the “river” was announced in 2011. Unofficial name given in honor of the Indian scientist Walia Hamza, who spent more than 45 years exploring the Amazon.

Largest rivers in the world

The Greatest Rivers of the World

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Today, no one can say for sure how many rivers there are in the world. After all, everything also depends on what can be considered a river and what can be considered a stream. So, for example, if you add up the length of all the rivers in Russia, you get more than 8 million kilometers. Their total number, if you count large and small, is close to 2.5 million. There are no more than 50 largest rivers on the entire globe, and their total length is about 200,000 km. But what does the source and mouth of the river consist of?

Geographical significance of the river

A river is a stream of fresh water that moves in a fixed channel and is replenished mainly by precipitation. Before you understand the characteristics of freshwater streams, you need to remember a few key terms:

• A channel is a depression along which the flow of water from a river follows. It is usually fixed, sinuous in shape with alternating shallow and deep places. Due to geographical changes or other factors, it may change, leaving behind holes and depressions. So, for example, in India there is the Kosi River, which makes its way almost every year. new way, washing away everything that comes in its way.

• The source is the beginning of the river. It could be a spring, a melting glacier, any other body of water, or the confluence of two water streams.
• The mouth is the place where a river ends, whether it flows into the sea, ocean or other water stream.
• A river system is not only the river itself, but also its tributaries.
• A river basin is a defined area from which all the water is collected. All basins are separated by watersheds, and their role is played by hills.

Main parameters of river characteristics

The main characteristics of rivers are their size, flow speed, flow, fall and type of food.

The difference between the heights of the source and the mouth is called the fall. The higher the fall, the greater the speed of flow in the river.

Current speed is measured in m/sec. It will not be the same everywhere; the areas have different terrain and the slope of the riverbed is different.

Water flow shows how many cubic meters passed in 1 second through the cross section of the riverbed.

The river is fed in several ways: by rainwater, after melting ice, from underground springs and glaciers. Rivers located in the tropics are fed by rain. Snow feeding near rivers temperate zones and located in the northern hemisphere, and mountain rivers are glacial. There are several main rivers:

1. Equatorial - only rains all year round.
2. Subequatorial - the river is fed by rain, but it is uneven and seasonal.
3. Subtropical - rain with a rise in river level winter period and shallowing in summer.
4. Subarctic is snow feeding, which ensures a rise in water levels in summer and a sharp shallowing in winter, when most of the rivers freeze over.
5. Ozerny - the river is fully nourished all year round and does not depend in any way on other types of nutrition.
6. Mountain - in high mountains at night the rivers become shallow, and during the day they are replenished due to the melting of glaciers and snow.

You can also very often hear about the river regime. But not everyone knows what a river regime is. What does it depend on? The answer is very simple, the river regime is the course of long-term, seasonal and daily changes in the river flow in the channel. Changes can happen very quickly, it all depends on where and under what conditions the river flows.

Rivers flow through the plains, flow down from the mountains, and during their entire life they can change their path several thousand times, become shallower or, conversely, become more full-flowing.

Features of river flow

And the mouth of the river is already known, but what are the features of the water flow in each of them? After all, it is known that there are rivers with standing water and quiet current, and there are those where the water runs at such a speed that it can demolish any, even the largest, obstacle in its path.

The nature of the flow and speed of the river depend on the topography, slope and fall of the water. On the plains, river flows are wide, calm, and their fall slope is small. Such rivers include the Volga, Danube, Dnieper, Neman. But there are also those that flow among the mountainous heights. They are distinguished by turbulent and strong streams; on their way there are many rapids and sometimes high waterfalls. Such rivers have a huge fall, which means that their flow pattern is completely different. Such streams include the Terek, Rioni, Tigris and Yangtze.

The full flow, regime, and sometimes nutrition of rivers depend on the climate. In humid conditions, rivers remain full at any time of the year, but in dry climates they very often dry out and are fed only by precipitation, and there is not very much of it in a year.

Mountain rivers are cold because they are fed by melting glaciers located on the peaks. But if you walk along the entire riverbed, then at the very end the water can be very warm, since during its journey it heats up under the scorching rays of the sun.

What is a mountain and lowland river?

We have already managed to figure out what a river regime is, but what type of rivers are there? After all, they can simply run among the plains or descend from high mountains.

Lowland rivers are water streams passing through flat terrain with small slopes and flow rates. Such rivers flow in developed valleys with a winding bed, where reaches and rifts alternate.

Mountain rivers originate in the mountains or foothills. They have steep slopes and rocky riverbeds cluttered with debris rocks. Such rivers are characterized by large slopes and flow speeds, and shallow depths. Often along the path of these rivers there are waterfalls and rapids, and erosion processes also predominate.

There are also mountain-plain rivers that begin far in the mountains, after which they gradually turn into a quiet lowland river.

5 largest rivers in the world

Every person knows the name of the largest rivers in the world. The list of the 5 largest and deepest rivers in the world is headed by the Amazon, which is considered the heart of South America. More recently, it was considered 2nd on the list of the largest after the Nile. But after scientists accepted the small source of the Ucayali as the true beginning of the river, it began to be considered the longest. Its length is more than 7 thousand km.

In second place was the African Nile River. It is considered a sacred river, since only thanks to it can people living in the harsh and very dry climate of Africa survive. During the rainy season, the river floods, allowing the population of Africa to engage in agriculture; rice is grown on its banks. The length of the second largest river in the world is just over 6800 km, and the river basin has an area of ​​more than 3 million square meters. km.

The Yangtze is another large river in the world, which is considered the main deep-water stream of Eurasia. This river can be considered a mountain-plain river, since it originates in the Tibetan Plateau, then passes through the Sino-Tibetan Mountains and then flows into the Sichuan Basin. The length of this very deep river is about 6.3 thousand km, and the basin area is about 1.8 million square meters. km.

The Yellow River, or Yellow River, is another major river in the world, with its source in the mountains of Tibet. Its length is about 5 thousand km, and the basin area is 700 thousand square meters. km.

The names of rivers located in Russia can be found on the map. Among them there is one that is included in the list of the 5 largest - this is the Ob. Its length is a little more than 5,400 km, and the basin area is almost the same as that of the Nile - 3 million square meters. km. This water flow originates in Russia, and then passes through Kazakhstan and ends its path in China.

The world's major rivers have great importance for industrial and economic development states in whose territory they flow. Rivers give life-giving moisture to people. In addition, there are a lot of fish in the rivers, which feed not only animals, but also humans.

List of the smallest rivers in the world

But not only large rivers exists on the planet. There are also the smallest ones, which have their own significance for the people living on its banks. The smallest rivers:

• Reprua - this river flows in Abkhazia, and its length is only 18 meters. In addition, it is considered the coldest river on the Black Sea coast.
• Kovasselva - this water stream is located on the Norwegian island of Hitra, and its length is no more than 20 meters.

Amazing rivers of the world

The characteristics of rivers are not only information about whether they are large or small in size. There are also unusual and amazing water streams on the planet that attract attention with their originality.

Caño Cristales is the most colorful river located in Colombia. Most often, locals call it the river of five colors. The river acquires such a bright and unusual variety of colors thanks to the algae living in its water. If you look at the water in it, you might think that a rainbow fell into the water.

Citarum is the most dirty river on the planet. It is located in Indonesia, and is dirty because more than 5 million people live in its basin. People dump all their waste into its waters. If you look at the river from afar, you won’t even immediately understand what it is; you get the feeling that you’re looking at a landfill.

The Congo is the deepest river on the planet. It flows in Central Africa, in some places its depth reaches 230 meters, and perhaps even more.

El Rio Vinegre is the most acidic river. It flows past the Purace volcano in Colombia. Its water contains more than 11 parts of sulfuric acid and 9 parts of hydrochloric acid. There can be no living creatures in this river.

Life in rivers: plants

The characteristics of rivers are not only nutrition, length and other parameters, but also animals and plants. After all, in every water flow, whether it is the largest or the smallest, has its own life. In every fast or quiet river, many plants have found their home, which adapt to life in a particular stream, with its flow characteristics, water temperature and other parameters.

River plants can be divided into 5 main groups:

1. Plants found in water and on land. They begin their growth at the bottom of the river, and their upper part rises above the water. These include reed, reed, horsetail, cattail and arrowhead.
2. Plants whose roots are attached to the bottom and whose leaves float on the surface of the water. Such plants are floating pondweed.
3. Plants with roots at the bottom, whose leaves remain in the water, are urut and common pondweed.
4. Plants are floating and have no roots at the bottom. One such plant is duckweed.
5. Plants that live in the middle layer of water - hornwort, filamentous algae and elodea.

River life: fauna

Characteristics of rivers are also animals that cannot exist anywhere except in water. Not only does it live in rivers a large number of species of fish, but also other living organisms:

• Plankton are living organisms that live in the water column; they seem to float in a body of water and surrender to the power of the current. Plankton is the main food for many fish.
• Benthos. This group includes bottom organisms.
• Nekton are actively moving animals that can overcome currents. Today, there are more than 20 thousand species of nekton, these include fish, squid, cetaceans, pinnipeds, turtles and others.
• Neuston - animal and plant organisms that live on the surface of water bordering the atmosphere.
• Pleiston is animal and plant organisms that are semi-submerged in water, i.e., capable of living simultaneously in both aquatic and air environments.
• Epineuston includes organisms that live on the surface film.
• Hyponeuston - organisms associated with the surface film, but living underneath it.
• Periphyton are organisms that live on the surface of objects submerged in water.

Mammals also live in the rivers: beavers, otters, muskrats, and reptiles: turtles, snakes, crocodiles.

How are rivers used?

Even in ancient times, people believed that water is life. They often built houses on the banks of rivers and reservoirs to make it easier for them to carry out everyday life. Using the river helps not only to do household chores, but also to run your household. Water from rivers is used for drinking, having been purified beforehand, used to prepare food for themselves and animals, and used for watering plants.

Today, water from rivers is purified at special stations and supplied through pipes to homes in large cities. Rivers are also often used for timber rafting, as a way to travel over long distances. They swim and fish in the rivers. Rivers are also very beautiful landscapes, it’s nice to sit on the shore and enjoy the fresh moist air, admiring the surroundings.

How much water is needed for industrial enterprises that also build closer to rivers?! Thanks to this proximity, any enterprise will be able to draw water from the reservoir. In distant countries - Africa or South America - where the climate is very dry and rivers often dry up, the main source of drinking for wild animals is these rivers, even if they are dry in some places. But during the rainy season they become full again.

Without rivers, our planet would not be as beautiful and real. They, like water sleeves, weave around the globe and give life-giving moisture, but the task of humanity is to make every effort to preserve their purity and beauty.

The classification of rivers by food sources still does not provide a sufficiently complete picture of the regime of rivers and the fluctuations in their flows and levels throughout the year. In this regard, B. D. Zaikov’s attempt to establish the types of regime characteristic of rivers in the USSR seems very interesting. B. D. Zaikov divides all rivers of the USSR into three main groups:

1) rivers with spring floods;
2) rivers with floods in the warm part of the year;
3) rivers with flood regime.

The rivers of the first group are characterized by periodically recurring spring floods, formed due to the melting of snow in their basins. The second group includes rivers in which floods occur in the warm half of the year and are caused by rainfall or melting of high-mountain snows and glaciers. Finally, the third group includes rivers characterized by frequent short-term floods that can occur at any time of the year; During periods between floods, they experience a sharp decrease in flow. The listed groups, in turn, are divided into a number of types, the distribution of which throughout the territory of the USSR is shown on the map (Fig. 27).

The majority of rivers in the USSR belong to the group of rivers with spring floods. According to the nature of the spring flood and other features of the regime, the rivers of this group are divided into several types, namely: Kazakhstani, Eastern European, Western Siberian, Eastern Siberian and Altai.

Rivers with Kazakhstan type regimes are distinguished by an exceptionally pronounced high wave of spring floods; during the rest of the year they are extremely low in water, and many of them dry up altogether. They are widespread in the arid semi-desert and steppe regions of Kazakhstan, the southern Volga region, on the northern edge of the Aral-Caspian Lowland, i.e. in places where snow is the main and almost the only source of river nutrition. As an example, pp. Hypy, Sary-Su, etc. The rivers of the Barabinskaya, Kulundinskaya and Ishimskaya steppes of Western Siberia and the upper reaches of the river have an almost similar nature of the regime. Tobola.

Eastern European type river regime, is characterized by high spring floods, low summer and winter low water periods and increased autumn runoff due to rain. The most striking example of this type of regime is the Volga. On rivers located in the more southern regions of the East European Plain, autumn floods are weakly expressed (Don and other rivers).

West Siberian type The river regime is characterized by low and extended spring floods, increased summer-autumn runoff and low winter low water. The smoothed out flood is determined not only by the flat nature of the relief, but also by the strong swampiness of the West Siberian Lowland. This type of regime is especially well expressed in the rivers of the forest zone: Western Siberia (Vasyugan, Ket, Om, etc.).

For rivers East Siberian type The regime is characterized by high spring floods, summer-autumn floods and exceptionally low flows in winter, up to complete freezing and the cessation of channel flow even on large rivers. This is explained by the paucity of groundwater supply to rivers in conditions permafrost. An example of this type of mode is pp. Aldan, Lower Tunguska, Kolyma, etc.

Altai type The river regime is characterized by low and extended floods, which have a ridge appearance on the graph, increased summer-autumn flow and low winter flow. The extended nature of the flood is mainly determined by the regime of snow melting in the mountains and the conditions of rainfall runoff. Snow melting in mountainous conditions, even within the boundaries of small basins, does not occur simultaneously over the entire area, but along separate altitude zones and slopes, due to which melt water enters the rivers simultaneously from relatively small areas, and this makes the flood protracted and causes relatively low amplitude of water level fluctuations. In cases where intensive snow melting occurs, individual, more or less high waves are observed, mainly in the frontal part of the main flood wave. Precipitation that falls in the form of rain also causes an increase in runoff in rivers, but rises of water from them are usually characteristic of the rear part of the main flood wave. In addition to Altai, rivers with this type of regime are common in the Caucasus, Central Asia and Sakhalin.

A group of rivers with floods in the warm part of the year. This group of rivers can be divided into two types: Far Eastern and Tien Shan.

For rivers with Far Eastern type The regime is characterized by low and highly extended floods in the warm part of the year, having a ridge appearance, and very low flows the rest of the time. The main source of nutrition for rivers of this type is rainfall. Many rivers completely freeze over in winter, and their channel flow stops. This type of regime covers rivers Far East, Eastern Sayan Mountains, Transbaikalia, Vitimo-Olek-Minsk mountainous country and Yano-Indigirsky district.

Tien Shan type in terms of the external nature of the flood, it is somewhat similar to the Far Eastern one, however, summer floods of rivers of this type have a different origin; The fact is that the flood is not formed. rain, and melt water formed from the melting of high mountain snows and glaciers. Thus, the runoff regime is closely related to the course of temperature, and its highest values ​​correspond to the period of greatest high temperatures air. This relationship is manifested not only seasonally, but also during the day (the daily variation of runoff, approximately corresponding to the daily variation of air temperature). It is characteristic that the maximum runoff usually lags somewhat behind the time when the maximum air temperature occurs. The Tien Shan type of regime is characteristic of the rivers of the mountain systems of Central Asia - the Tien Shan and Pamir - and the rivers of the high-mountain regions of the Greater Caucasus and Kamchatka.

A group of rivers with a flood regime. Among the rivers of this group, the following characteristic types can be distinguished: Black Sea, Crimean and North Caucasian.

Black Sea type regime formed under warm and humid climate Western Transcaucasia, is characterized by flood conditions throughout the year. It is caused by heavy rains from humid winds blowing from the sea. A typical example is R. Sochi. The tributaries of the Dniester flowing from the Carpathian Mountains have a roughly similar regime.

By the rivers Crimean type regime, floods are observed throughout the year, with the exception of the summer or summer-autumn period, when low water sets in, and many rivers even dry up; an example is r. Salgir. The Lenkoran River in the Caucasus and the Zhmud Heights in the Baltic States are close to this type in their regime.

Rivers with North Caucasian type regimes have a stable low-water period in the cold part of the year, and in summer period They are characterized by frequent floods. These include mainly watercourses flowing from the eastern half of the northern slope of the Greater Caucasus.