Nutrition and regime of rivers. Classifications of the water regime of rivers What waters do rivers feed on

The other part evaporates. However, with the unity of the atmospheric origin, in the final analysis, of all river waters, the direct ways in which water enters the rivers may be different. There are four types (or sources) of water supply of rivers: rain, snow, glacial and underground. For rivers in conditions warm climate main view food - rain. The flow of such major rivers as the Amazon, the Ganges and the Brahmaputra, the Mekong, is formed mainly by rainwater. This type of river nutrition is the most important on a global scale: it accounts for more than a third of the total river water flow. The second most important is snow nutrition. Its role is very large in the feeding of rivers in a temperate climate (at least 1/3 of the water flow). The third place in terms of the volume of water entering the rivers is occupied by groundwater (on average, it accounts for about 30% of the volume of river water runoff). It is underground nutrition that determines the constancy or long duration of the river flow throughout the year, which ultimately creates the river. The last place in terms of importance in the water supply of rivers is occupied by glacial nutrition (about 1% of the flow of the world's rivers).

rain food

Each rain is characterized by a layer of precipitation (mm), duration (minutes, hours, days), intensity of precipitation (mm per minute, mm per hour) and area of ​​distribution (km 2). Depending on these characteristics, rains can be subdivided, for example, into showers and showers.

The intensity, distribution area and duration of rainfall determine many features of the formation of river water runoff and groundwater replenishment. The greater the intensity, distribution area and duration of the rain, the greater the magnitude of the rain flood. The greater the ratio between the area of ​​distribution of rain and the area of ​​the entire river basin, the greater the magnitude of the possible flood. Extreme floods occur for these reasons, usually only on small and medium-sized rivers. Replenishment of groundwater, as a rule, occurs during prolonged rains. The lower the humidity of the air and the drier the soil during the period of rain, the greater the cost of water for evaporation and infiltration, and the lower the amount of rain runoff. On the contrary, rains falling on moist soil at low air temperatures give a large amount of rain runoff. Thus, the same rain, depending on the state of the underlying surface and air humidity, can in some cases be runoff-forming, and in others - almost no runoff.

snow food

IN temperate latitudes The main source of water supply for rivers is water accumulating in the snow cover. Snow, depending on its density and the thickness of the snow cover, can give a different layer of water when melting. Water reserves in snow (a value that is very important for predicting the volume of melt runoff during a flood) is determined using snow surveys. Water reserves in the snow in the river basin depend on the amount of winter precipitation, which in turn is determined by climatic conditions. Water reserves in the snow cover are usually distributed unevenly over the area of ​​the river basin - depending on the height of the terrain, exposure of slopes, uneven terrain, the influence of vegetation, etc. It is necessary to distinguish between the processes of snowmelt and water loss of the snow cover, i.e. the flow of water not retained by snow to the soil surface. Snowmelt begins after the air temperature reaches positive values ​​and under the condition of a positive thermal balance on the snow surface. Water return begins later than the beginning of snowmelt and depends on physical properties snow - granularity, capillary properties, etc. Runoff occurs only after the start of water loss.

underground food

It is determined by the nature of the interaction of underground (ground) and river waters. The direction and intensity of this interaction depend on the relative position of the water level in the river, the height of the roof of the water-resistant layer of soil and the level of groundwater, which in turn depends on the phase of the river's water regime and hydrogeological conditions. Underground feeding of rivers is usually greatest during low water, when groundwater enters the river. During high water, the water level in the river is usually higher than the groundwater level and therefore at this time the river feeds the groundwater.

Glacial nutrition

Only rivers flowing from regions with high mountain glaciers and snowfields have such food. The contribution of glacial nutrition to river water runoff is the greater, the greater the proportion of the total area of ​​the river basin is occupied by glaciers. This contribution is greatest in the uppermost parts of mountain rivers.

For each river, the proportion of individual types of water supply may be different. Determining the contribution of various types of nutrition to river water runoff in each specific case is an extremely difficult task. It can be most accurately solved either with the use of "tagged atoms", i.e. by radioactive "marking" of waters of various origins, or by analyzing the isotopic composition of natural waters. A simpler, but approximate way to distinguish between different types of food is a graphical division of a river hydrograph.

Currently, the most common classification of rivers is by type (or source) of food. To determine the degree of predominance of one or another type of nutrition, three gradations were adopted. If one of the types of food provides more than 80% of the annual water flow of the river, we should talk about the exceptional importance of this type of food (the contribution of other types of food is not taken into account). If the share of this type of food accounts for from 50 to 80% of the water runoff, then this type of food is given priority (other types of food are mentioned if each of them accounts for more than 10% of the annual water runoff). If none of the types of food provides more than 50% of the annual flow, then such food is called mixed and sometimes some types of food are indicated in descending order of their contribution to the river flow. The specified ranges of gradations (80 and 50%) refer to all types of nutrition, except for glacial. For glacial feeding, the corresponding gradation ranges are reduced to 50 and 25%.

Most of the rivers in the territory former USSR has a predominant snow supply. The rivers of Northern Kazakhstan and the Trans-Volga region have almost exclusive snow supply. Rain-fed rivers occupy the southern part of the territory east of Baikal, as well as the Yana and Indigirka basins, Black Sea coast Caucasus, Crimea and North Caucasus. Rivers in the Caucasus and Central Asia are fed by glaciers.

V.N. Mikhailov, M.V. Mikhailova

Feeding the river

Feeding the river

inflow, inflow into the river of waters of various origins. It can be rain, snow, underground, glacial. Usually it is mixed with the predominance of one of the types of food. During the spring floods snow feeding of rivers clearly predominates, during the period low water- underground.
Of particular interest to various branches of water management is the ratio of surface and underground feeding, since the underground component of the river runoff is stable over time and practically does not require regulation. For the rivers of Russia, underground feeding is a little more than 20% of the river flow, while for the rivers the globe this share in cf. exceeds 30%.
Definition of contribution various sources river feeding is carried out on the basis of the division of hydrographs of river flow, i.e., graphs characterizing the change in time of water flow for a year or part of a year (season, flood, flood or low water).
The hydrograph is built on the basis of observational data at hydrological stations and posts. The division of the hydrograph is carried out, focusing on the general characteristic features of the flow of water coming from various sources of nutrition, which are manifested, in particular, in different speed water movement. During the period of max. water consumption, when its level in the river can be higher than the water level in individual underground horizons, it is possible to recharge them from the river. Then, as the water levels in the river decrease, this water returns to it. This process is called "coastal regulation".

Geography. Modern illustrated encyclopedia. - M.: Rosman. Under the editorship of prof. A. P. Gorkina. 2006 .

See what "river food" is in other dictionaries:

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• "With other equal conditions the country will be richer
• flowing waters, the more abundant the precipitation and the less
• evaporation from the surface of soil and water, and plants.
• Thus,
• rivers can be seen as a product of the climate.”
• A. I. Voeikov

River nutrition. River feeding types. River power sources.

River nutrition depends on many factors. The main one is the size. drainage basin, since a large and stable flow requires a significant drainable area. The climate is the deciding factor; often more large pool the rivers of the dry region provide as much water as the much smaller river basin of the humid region. In the absence of precipitation, the rivers switch to groundwater supply.

Currently, there are several classifications of rivers according to the types of food and water regime, the authors of which are A. I. Voeikov, M. I. Lvovich, and M. B. Zaikov. The first classification, subsequently taken as a basis by other scientists, was proposed by Alexander Ivanovich Voeikov in 1884. The classification of A. I. Voeikov has not lost its relevance in our time. Subsequently, this classification was improved by other scientists.

Classification of rivers according to nutrition and water regime according to A. I. Voeikov ( Climate classification rivers).

Among the types of river nutrition, A.I. Voeikov identified two main types - snow and rain, and two derivatives - glacial and mixed. In this classification, in addition to various types rivers (for example, the absence or presence of floods on rivers), some phases of the water regime of rivers, the main forms of relief (mountains and plains), as well as geographical position selected types of rivers. In the water cycle, Voeikov considered evaporation as the opposite of precipitation, and believed that the relationship between these opposite processes determines the regime of rivers and the density of the river network.

Depending on the sources of water supply and climate, the scientist identified nine main types of rivers.

1) Type A. Rivers that receive water from melting snow on the plains and on low, up to 1000 m, mountains. In its pure form, this type does not exist anywhere. The rivers closest to it are in the northern part of the North American continent and Siberia, where the duration of the snow cover is 8-10 months.

2) Type B. Rivers that receive water from snowmelt in the mountains. In its pure form, this type also does not exist, but there is a greater approximation to it than to type A. Rivers of this type flow in the western parts of the mountain ranges located in the center of Asia. Among them are such rivers as the Syr-Darya, Amur-Darya, Upper Indus, Tarim.

3) Type C. Rivers that receive rain and have high water in summer period. This type of rivers is confined to tropical rains and monsoon rains.

4) Rivers of Type D. They are characterized by high water in spring or early summer, associated with snowmelt, while receiving a significant part of the water from rains. Rivers of this type cover the entire European Russia, North and Western Siberia, East Germany, northern USA and parts of Canada.

5) Type E rivers - receiving water from rains. These rivers are fuller in the cold months of the year, but the difference is small. Rivers of this type prevail in Central and Western Europe.

6) Type F. Rivers receiving water from rains. These rivers are fuller in winter period, and the difference is significant. Rivers of this type flow in Southern Europe (Spain, Italy).

7) Type G. Absence of permanent streams, including rivers, due to the dryness of the climate. This type refers to most of Arabia, the Sahara, most of the central plateaus of Asia, part of the territory South America, parts of the Aral-Caspian lowland, to most of inland Australia, vast plateaus North America.

8) Type H. Rivers that receive water only during a short period of rains and some time after. The rest of the time, they either dry up or turn into a series of puddles with an underground current in between. Such rivers include the rivers of the part of the Kyrgyz steppes, the steppe part of the Crimea, part of Mongolia, the rivers of the steppes along the lower reaches of the Araks and Kura, the rivers of many places in North America and Australia.

9) Type I. Absence of rivers due to continuous coverage by glaciers and snow. Here the rivers are replaced by glaciers with under-ice streams carrying excess rainfall to lower valleys or evaporation.

Classification of rivers according to nutrition and water regime according to M. I. Lvovich.

M. I. Lvovich improved the classification of A. I. Voeikov due to quantification sources of river feeding and seasonal distribution of runoff. To the rain, snow and ice sources of food allocated by Voeikov, Lvovich added an underground (ground) type of food.

For each of the four power sources, there are three gradations:

1. "Almost exclusively." The main power source has more than 80% of the annual flow, other power sources are not taken into account.

2. "Mostly" - if the share of annual runoff attributable to the main source of food is from 50 to 80%.

3. "Prevails." The contribution of the main source does not exceed 50%.

The same gradations are accepted for characterizing the seasons of the year - spring, summer, autumn and winter. Thus, Lvovich's classification system makes it possible to calculate a combination of 12 groups of food sources (rain, snow, ice, soil, three gradations each) with 12 groups of river runoff distribution by season (spring, summer, autumn, winter, three gradations each). in each). It turns out 144 various options river regime. Some of the options are theoretically possible, for example, the predominance of glacial or snow feeding in winter, but some combinations that are theoretically possible have not yet been discovered in practice.

From natural combinations of power supply combinations with different options distribution of runoff, 6 main zonal types of the water regime of rivers were identified: equatorial, tropical, subtropical, temperate, subarctic, polar.

Natural combinations of various combinations of power sources with different variants of runoff distribution made it possible to identify the main zonal types of water regime lowland rivers: polar, subarctic, temperate, subtropical, tropical and equatorial.

Polar type rivers- most of the year frozen, during the period short summer have glacial feeding and runoff.

Rivers of the subarctic type. They are mainly fed by snow, underground feeding is almost completely absent due to permafrost. In winter, many small rivers freeze to the bottom and have no flow. Opened in late May - early June, summer flood. TO this type rivers include Khatanga.

temperate rivers, in turn, are subdivided into four subtypes of rivers according to the seasonal distribution of runoff and sources of food:

- rivers on the western coasts with a maritime climate are predominantly rain-fed with a uniform annual distribution of runoff with a slight increase in winter due to reduced evaporation (Seine, Thames and others);

- rivers flowing in areas with a transitional climate from maritime to continental have a mixed supply with a predominance of rain over snow, with a low spring flood (Elbe, Oder, Vistula and others);

- rivers flowing in the regions continental climate have mainly snow nutrition and spring floods (, and others);

- the rivers east coasts with a monsoon climate, they are mainly fed by rain and summer floods (Amur).

Subtropical rivers They are predominantly rain-fed, but according to the seasonal distribution of runoff, they are divided into two subtypes:

- near rivers on the western coasts of continents with a Mediterranean climate, the main flow is winter (Guadalquivir, Guadiana, Duero, Tajo and others);

- near the rivers flowing on the eastern coasts in the monsoon climate, the flow is summer (Huang He, tributaries of the Yangtze).

Tropical rivers. The runoff of tropical rivers is formed due to summer monsoon rains in the subequatorial climate zone and predominantly summer rains on the east coasts tropical zone, therefore, these rivers are characterized by high water in the summer. Rivers: Orinoco, Zambezi, and others.

For rivers of the equatorial type characterized by abundant rainfall, large and relatively uniform runoff throughout the year. An increase in runoff is observed in the autumn of the corresponding hemisphere. Rivers of the equatorial type: Amazon, Congo and others.

This is about lowland rivers. Mountain rivers, on the other hand, are characterized by vertical zonality: with an increase in the height above sea level of the mountains near the rivers, the share of snow and then glacial nutrition increases. In mountain, and especially in high mountain rivers, the flood period occurs in the summer.

The most intense, and often even catastrophic summer floods occur on rivers that originate high in the mountains, and in the middle and lower reaches are abundantly fed by monsoon rains. These are the rivers Indus, Ganges, Mekong, Brahmaputra, Irrawaddy, Yellow River, Yangtze and others.

Classification of Russian rivers according to the hydrological regime B. D. Zaikova.

In Russia, along with the classification of rivers by M. I. Lvovich, the classification of rivers according to the hydrological regime proposed by B. D. Zaikov is very popular.

The hydrological regime includes the following phases: high water, low water, floods, etc. In accordance with this typification, the CIS are divided into three groups.

1. Rivers with spring floods. Among this group stand out:

- rivers of the Kazakh type, which are characterized by a pronounced short flood and dry low water for the rest of the year;

- rivers of the Eastern European type, having a high, short flood, winter and summer low water;

- rivers of the West Siberian type, which are characterized by extended low floods, increased runoff in summer and low water in winter;

- rivers of the East Siberian type, characterized by high floods, summer low water with rain floods, and very low winter low water;

- rivers of the Altai type - uneven low and extended floods, increased runoff in summer, low water in winter.

2. Rivers with summer floods and floods. Among this group are:

- rivers of the Far Eastern type, which are characterized by low winter low water, as well as a low flood extended over time with floods of monsoon origin;

- rivers of the Tien Shan type, having an extended low flood of glacial origin.

3. Rivers with a flood regime. It also highlights:

- rivers of the Black Sea type, which are characterized by floods throughout the year;

- rivers of the Crimean type, characterized by floods in the winter and spring periods, and low water in the summer and autumn periods;

- rivers of the North Caucasian type - floods in summer, low water in winter.

Summarize summarizing all of the above. All rivers are fed by snow, rain, ice and soil. In its pure form, each of the types of nutrition is practically not found, but a mixed type is more common. Snow, rain, and glaciers - these food sources have the same origin - precipitation. Part of the liquid precipitation under certain conditions forms a surface runoff and serves as a direct source of river nutrition during flood periods. Solid precipitation accumulates in the form of snow cover on the surface of the earth. On the plains and high mountains the snow accumulated during the winter melts in the warm season and also serves as a source of power for the rivers. In the higher mountains, the snow that has accumulated in some years does not completely melt, replenishing the reserves of eternal snow and giving rise to glaciers.

The situation with groundwater is somewhat different. Much of the groundwater is also formed by precipitation, waters of marshes, lakes, reservoirs and rivers that infiltrate the earth to a certain depth. The second way the formation of groundwater is the condensation of water vapor in rocks. However, there is a third way, which differs from the other two - the juvenile formation of waters. The theory of juvenile water formation was put forward by the Austrian geologist E. Suess in 1902. According to this theory, part of the groundwater in areas of modern or recent volcanic activity, characterized by elevated temperature and a significant concentration of salts, was formed from gaseous products, released in abundance during the differentiation of the magma chamber. Later studies showed that pure juvenile waters also do not exist, and all waters that have arisen in different ways mix with each other.

Mode means order, control. This term is used to denote order in many areas of human activity, as well as in the nature around us. One example of this is the river regime. But if in everyday life a person adheres to a certain routine, then in the river regime he often takes an observational position - he states the fluctuations that occur in the life of the river, and only in some cases can intervene in the regime of the watercourse in order to change it.

Any object of the surrounding world can be described by giving it a characteristic. Including the characteristic and superficial water bodies- oceans, seas, lakes, rivers, swamps. This characteristic is called hydrological. It necessarily includes hydrological regime rivers - collection characteristic features that change the state of the river over time.

The hydrological regime is manifested in daily, seasonal and long-term fluctuations in the water level and water content (together this constitutes the water regime), ice phenomena, water temperatures, the amount of suspensions in the stream, water hydrochemistry, changes in the river bed, flow rates, waves and other phenomena and processes, occurring continuously in the life of the river. All of the above and other elements of the hydrological regime together determine the regime of the river.

Depending on whether or not there is a hydraulic structure on the river that can influence the hydrological regime, rivers have a regulated regime or a natural (domestic) regime. Of all the elements of the river regime, river runoff is of great practical importance. Its value determines the watering of the territory, hydropower territorial reserves, the size waterways messages in this area.

The river regime depends on many factors: climate, land relief, water supply, and others. The main factor — river water obtained from the water cycle in nature. The waters supplying food to the rivers are divided into glacial, snow, rain and underground. The same terms are used when defining rivers. IN individual cases it is difficult to clearly enough define the dominance of one river (the type of river feeding), and then the term “mixed type of feeding” is used.

Phases (periods) of the water regime according to characteristics divided into high water, low water and floods. The flood occurs annually in a certain season of the year, is marked by a long rise in the level with high marks and the largest water content in comparison with other phases. Low water is also seasonal and differs low level and the least water content; at this time the river is fed mainly groundwater. Floods tend to be fast and short-lived. high levels with high water consumption; they occur as a result of rains, snowmelt.

Characteristics of the Nile River: the length of the river with the rivers that form it in the Rukakara-Kager-Nile river system is 6852 km - this is the second longest of the Earth's rivers. The Nile flows from south to north towards the Mediterranean Sea. The course of the river is stormy in the upper and middle parts, slow in the lower part; to the mouth of the Nile is divided into numerous branches and near mediterranean sea forms the largest delta. The Nile is the source of life in the Sahara Desert. Almost all (97%) settled along its coast. The permanent flow of the Nile is provided by year-round equatorial rains (Blue Nile drainage area) and rains in southern regions(watershed of the White Nile), and rains on the Abyssinian highlands, washing away loose soils. The river flow carries suspensions, depositing nutrient silt in the delta, on the fields of which the Egyptians harvest up to 3 times a year. To combat floods, in which the area of ​​Cairo rose by 8 m, which threatened disaster for the population, the famous Aswan Dam was built. And now the regime of the Nile River in the lower reaches is regulated. But although the Nile is 3 times longer than the Volga, in its channel it carries a volume of water 2 times less.