In August 2013, there was a grandiose flood, from which 98 thousand inhabitants suffered. The Amur, the largest river in these places, emerged from its banks. Flooding scientists called the largest in the last hundred years. The river flooded territories located thirty kilometers from its usual course.
The scale of the tragedy made many people think about why the Amur is flooding, and whether it is possible to somehow prevent the disastrous consequences of the flood.
A bit of theory
Rivers that are in sharply defined seasons or originate high in the mountains, among glaciers, always have high water and low water. In nature, there is an eternal exchange of water. Moisture, evaporating from the oceans, turns into clouds that carry precipitation. Rain, falling on the ground, penetrates into and saturates the rivers, which, in turn, carry their waves to the sea. Therefore, before you figure out why Amur is spilling, you need to understand what it eats.
The specificity of the river
We are accustomed to the fact that the flood near the rivers of Russia falls in the spring, since the vast majority of them are fed by snow. When it gets warm, melt water overflows the Volga, Oka, Dnieper and similar blue arteries. Mezhen (the shallowest occurs in them in the summer and the first half of autumn, when there is little precipitation. But the Amur is not such a typical river. It flows in the monsoon climate zone, characterized by the fact that east winds blow here from the Pacific Ocean in summer.
It is in the climatic features that one should look for the answer to the question of why the Amur spills.
Winters in this region are severe, but with little snow. Somewhere in November, in the Amur basin, as well as on its tributaries - the Zeya, Bureya, Ussuri and Sungari - freeze-up begins, which opens only in early May. For almost half a year, these rivers receive only underground food - from groundwater and springs. Due to the lack of snow in the winter, spring floods are not observed on local rivers.
But when the summer monsoons begin to blow, bringing downpours and typhoons from the Okhotsk, the water level in the Amur River and its tributaries rises sharply, since these rivers are fed mainly by rain.
Can disaster be prevented?
If the flood in the Amur occurs every summer, then why is August 2013 inscribed in the history of Russia as a black date? There is also such a geographical concept as a flood. It comes from a riot of the elements and has a sudden, very sharp character. The flood occurs due to strong and prolonged downpours (for example, when a monthly rainfall occurs in 1-2 days) or due to the sharp melting of snow in the mountains. And in 2013, a typhoon was added to the action of the wet summer monsoon. An important factor was that the storm drove the river waters back into the mainland from a shallow estuary. and dam failure. Thus, it is not enough to know why the Amur is flooding, one must also be aware that August-September is the time of typhoons.
Can the problem be solved? Yes, as the experience of many countries shows. The same Chinese, whose settlement area runs along the other side of the Amur, are investing a lot of money to strengthen it from erosion. In Europe, a cascade of reservoirs is installed in the upper reaches of rivers and on tributaries. This saving chain makes it possible to accumulate excess water, so that later it can be gradually lowered down during low water. We need to adopt this experience, and not be content with the fact that Amur's level is within the normal range today.
The territory of the Far East stretches along the coast of the Pacific Ocean for 4500 km. It is located in the zone of contrasting processes and phenomena. As already noted in our review, heterogeneous blocks of the earth's crust, various air masses, cold and warm sea currents interact here, representatives of the northern and southern flora and fauna coexist nearby. All this determines the great diversity of natural conditions.
The Far East is located in the zone of interaction of large lithospheric plates. The Pacific plate is moving under the continental Eurasian one. This is reflected in many features of nature. So, almost all mountain structures stretch parallel to the Pacific coast. The ridges of the Koryak Highlands and the Sredinny Ridge of Kamchatka are curved towards the continent. The southern outer arc of the mountain structures is bent towards the ocean and consists of the Eastern Range of Kamchatka and the ridge of the Kuril Islands. These islands are the peaks of the highest (about 7000 m) mountains rising from the bottom of the sea. Most of them are under water. Most of the mountain structures of the Far East were formed in the Mesozoic. Evidence is intense earthquakes and seaquakes, the centers of which are located both in the bowels of mountain structures and at the bottom of sea basins and deep-sea depressions - gutters. Seaquakes are accompanied by the formation of giant waves - tsunamis, which rapidly fall on the Far East coast, causing catastrophic destruction.
The arcuate ridges also include volcanic mountains. The largest of them, Klyuchevskaya Sopka (4750 m), systematically ejects ash and lava. Volcanic processes are accompanied by geysers and numerous sources of thermal waters. In Kamchatka, they are used for heating buildings and greenhouses, and for generating electricity.
Many mountains of the Far East are composed of hardened lavas, tuffs, pumice and other volcanic rocks.
In the south there are mountains, highlands and plateaus, formed as a result of the build-up of the continental lithospheric plate from the east at the expense of the oceanic one. Therefore, the western parts of the mountain structures are composed of more ancient folds than the eastern ones. So, Sikhote-Alin from the west consists of Mesozoic folded structures, and from the east - Cenozoic. The mountains of Sakhalin are completely represented by Cenozoic folded structures of the earth's crust. The intrusion of igneous rocks into sedimentary strata led to the formation of deposits of iron, polymetallic and tin ores. Sedimentary rocks contain deposits of coal, oil and gas.
The climate of the entire Far East is determined by the interaction of continental and marine air masses of temperate latitudes. In winter, currents of cold air rush to the southeast from the powerful Asian High. Therefore, the winter in the Far East is very severe and dry. In the northeast, along the edge of the Aleutian Low, the cold continental air of Eastern Siberia interacts with the relatively warm sea air. As a result, cyclones often occur, which are associated with a large amount of precipitation. There is a lot of snow in Kamchatka, blizzards are not uncommon. On the eastern coast of the peninsula, the height of the snow cover in some places can reach 3 m. Snowfalls are also significant on Sakhalin.
In summer, air currents rush from the Pacific Ocean. Maritime air masses interact with continental air masses, as a result of which monsoon rains occur throughout the Far East in summer. As a result, the largest Far Eastern river, the Amur, and its tributaries flood not in the spring, but in the summer, which usually leads to catastrophic floods. Devastating typhoons often sweep over coastal areas, coming from the southern seas.
The interaction of continental and marine air masses, northern and southern currents, a complex relief that combines mountains and lowlands, closed basins - all this together leads to a diversity of the vegetation cover of the Far East, to the presence of northern and southern species in its composition. In the northern lowlands there are tundras, into which larch forests enter from the south along the rivers. Most of Kamchatka is occupied by sparse forests of stone birch and larch, and thickets of dwarf pine with alder and lichens grow on the slopes of the mountains.
Northern Sakhalin is characterized by sparse larch forests, while southern Sakhalin is characterized by impenetrable bamboo thickets and spruce-fir taiga. On the Kuril Islands, in Primorye and the Amur Region, where the summer is warm and humid, coniferous-broad-leaved forests of a rich species composition grow. They consist of Korean cedar, spruce, fir, linden, hornbeam, Manchurian walnut, pear and many other species. Dense thickets of trees are intertwined with vines, grapes and lemongrass. There are many medicinal herbs in the forests, including ginseng.
Northern and southern species of animals are found in the Amur and Primorye regions. Here live such Siberian species as reindeer, elk, sable, squirrel, and such southern species as the Amur tiger, spotted deer, black deer, raccoon dog. The Kuril Islands are characterized by seals, fur seals and sea otters.
In most of the Far East, agriculture is difficult. But on the southern plains with fertile chernozem-like and brown forest soils, wheat, rice, soybeans, potatoes and vegetables are grown.
Author ***Elizabeth*** asked a question in Other about cities and countries
Why do the rivers of the Far East overflow in summer and spring? and got the best answer
Answer from Vadim Levshin[guru]
The climate of the entire Far East is determined by the interaction of continental and maritime air masses of temperate latitudes. In winter, currents of cold air rush to the southeast from the powerful Asian High. Therefore, the winter in the Far East is very severe and dry. In the northeast, along the outskirts of the Aleutian Low, the cold continental air of Eastern Siberia interacts with warm sea air. As a result, cyclones often occur, which are associated with a large amount of precipitation. There is a lot of snow in Kamchatka, blizzards are not uncommon. On the eastern coast of the peninsula, the height of the snow cover can sometimes reach 6 m. Snowfalls are also significant on Sakhalin.
In summer, air currents rush from the Pacific Ocean. Maritime air masses interact with continental air masses, as a result of which monsoon rains occur throughout the Far East in summer. The monsoon climate of the Far East covers the Amur Region and Primorsky Territory. As a result, the largest Far Eastern river, the Amur, and its tributaries flood not in the spring, but in the summer, which usually leads to catastrophic floods. Devastating typhoons often sweep over coastal areas, coming from the southern seas. But at the same time, a warm, albeit very short, summer makes it possible to develop agriculture in the open field.
Answer from 3 answers[guru]
Hey! Here is a selection of topics with answers to your question: why do the rivers of the Far East overflow in summer and spring?
Lesson Far East: land of contrasts
Goals and objectives of the lesson:
1. To form an idea about the features of the nature of the Far East.
To acquaint with the history of discovery, exploration and settlement of the territorytorii of the Far East. 2.To form the ability to work with different sources of information
3. Raise interest in the subject
Equipment:
Maps: physical Russia,
During the classes
I . Organizing time
II . Repetition. Checking homework
Test tasks
Learning new material
Guys, today we have studied the main features of the nature of the Far East. This is the last natural region of Russia. Today we will independently study the Far East, using the text of the textbook, atlas maps, books, paintings.
You are members of an expedition to the Far East. The most amazing region, mysterious, contrasting: here you can see polar bears and tigers, brown and Himalayan bears, lichens and creepers. Only in the Far East of Russia there are active volcanoes and geysers.
1. Let's get acquainted with the composition of the Far East. On the physical map, find the following objects:
Seas: Bering, Okhotsk, Japanese, Chukchi.
Bays: Anadyr, Shelikhov, Peter the Great, Penzhina Bay
Capes: Dezhnev, Lopatka.
Islands: Wrangel, Ratmanov, Commander, Kuril, Sakhalin, Shantar.
Peninsulas: Chukotka, Kamchatka
Volcanoes: Klyuchevskaya Sopka, Koryakskaya Sopka, Shiveluch, Tolbachik, Alaid.
Ridges: Sredinny, Dzhugdzhur, Bureinsky, Sikhote-Alin.
Uplands: Chukchi, Koryak.
Plains: Zeya-Bureinskaya.
Work with your desk mate, taking turns pointing out the found nye objects.
Why are there active volcanoes in the Far East and why do I visit! strong earthquakes?(In the Far East - a young earth's crust, here is the boundary of lithospheric plates.)
Why is mountainous relief prevailing here?(The territory of the Far East is located in the area of Cenozoic folding, and mountainous landforms correspond to the folded areas.)
3. You found out that the Far East belongs to the area of Cenozoic folding. So the age of the Far East is ...(young). Tectonic territory is a mobile territory, because it is located ...(on the border of lithospheric plates).
There are frequent earthquakes and...(volcanic eruptions) giant waves in the sea...(tsunami). Remember the 1995 earthquake that wiped out the city...(Neftegorsk).
4.
Let's find minerals of the Far East.
On Sakhalin... (oil, coal, gas).
Primorye is rich ...(polymetallic ores, tin). In Kolyma, in Chukotka they mine ...(gold).
5. What type of climate is in the Far East? Read the textbook
The climate of the Far East is greatly influenced by: Great length with ...(north) on the ...(south). The Far East stretches from the Arctic Circle to ... the latitude of Sochi. So the climate is...(Arctic to temperate).
The Pacific Ocean influences the coast as ...(the ridges are stretched along the coast and are an obstacle to temperate marine air).
The winds that prevail here...(monsoons). They determine the main feature of the climate: precipitation is torrential and falls ...(summer). Snow falls in winter...(few).
Using a physical map, find the rivers: Amur, Zeya, Bureya, Selemzha, Anadyr.
Lake... (Hanka) the largest.
The rivers frightened the first settlers. I was especially frightened by the swiftness, unprecedented abundance of water in the Amur, sudden floods, the strongest ofwhich happens not in the spring, but ...(summer).
Natural areas in the Far East from the tundra in the north to mixed forests in the south - they are called ...(Ussuri taiga).
There are many endemics in the Far East: ginseng, Amur velvet, Manchurian walnut, Amur grapes, lemongrass, Korean cedars, white, black, yellow, and iron birches. In the forest - tigers and brown bears.
4. Fixing
Mixed views of north and south. Why?
I know what Khanka, Ussuri taiga, tsunami, monsoon, Sikhote-Alin, ginseng, Klyuchevskaya Sopka, geyser are.
I can explain. Why do the rivers of the Far East overflow in summer and spring?
Why are there still earthquakes and volcanism?
Homework
§41.
Prepare messages: about Kamchatka; about Chukotka; about Sakhalin;
The water regime of the rivers of the Far East differs sharply from the regime of the rivers of other regions of the country. They are characterized by relatively low spring floods, powerful summer floods from heavy rainfall, and exceptionally low winter low water.
Table 1. Share of power sources for some rivers in the Far East Territory
The main food (about 70%) of the rivers of the region is received by summer rains of a stormy nature; snow nutrition plays a secondary role, and soil nutrition in the presence of permafrost is extremely poor, as can be seen from Table. one.
Between the spring flood and the summer floods in June, a short-term low water is sometimes observed, but for the most part the floods follow immediately after the spring rises. The number of summer rain floods is different and ranges from 4 to 6 or more during the summer season. The highest floods, sometimes causing catastrophic floods, are observed most often in late July - early August.
A severe flood was observed in 1928; it covered the Zeya basin, the middle and lower reaches of the Amur. The cause of the flood was very heavy precipitation that fell in the second and third decades of July in the Zeya basin and exceeded the norm by 200 mm. So, for example, in July 1928, 406 mm fell at the Bomnak weather station (upper reaches of the Zeya), with a July norm of 93.6 mm and an annual precipitation of 455 mm. Thus, for this one month, the amount of precipitation amounted to almost an annual norm.
Along with the noted common features, the regime of the rivers of individual parts of the vast territory of the Far Eastern Territory is somewhat different. Thus, the rivers of the Zeya and Bureya basins are characterized by a somewhat increased snow supply compared to other rivers; the rivers of Transbaikalia, with very small snow reserves, on the contrary, are distinguished by a very weakly pronounced spring flood; the rivers of Primorye, in the absence of permafrost, receive more intensive ground feeding.
The highly dissected topography and the presence of permafrost favor the rapid runoff of surface water. Under these conditions, the runoff coefficient is quite high, usually about 0.6, and in some places (Sikhote-Alin) - up to 0.85. The annual flow rate is 6-8 l / s km 2. The least water-bearing are the rivers of the Shilka and, especially, the Argun basins. Here the annual runoff modules are 1-2 l/s km 2 . Such a low relative water content of these rivers is explained by the arid steppe climate of Transbaikalia, which is characterized by low rainfall and low runoff coefficients equal to 0.2-0.3 on average. The basins of the Selemdzhi and Bureya rivers, as well as the Ussuri, are distinguished by high water content, where the annual runoff module in the mountainous parts of their basins reaches 13-16 l / s km 2.
The maximum flow on the rivers of the Far Eastern Territory is observed during the passage of showers. The maxima formed in spring due to snowmelt are usually much smaller than summer floods in size. The maximum runoff modules on the rivers of the Far East Territory reach very high values, especially on the small rivers of Primorye (Lyanchikhe - 6500 l / s km 2).
Table 2. Intra-annual distribution of runoff of some rivers in the Far East Territory
With the onset of cold weather, the rivers quickly become shallow, their costs become very small; many rivers, even large ones in terms of catchment area, freeze over. In winter, water discharges are close to zero in the middle reaches of the Zeya and Bureya rivers. In some years Shilka near Sretensk completely freezes over. In general, winter periods are characterized by extremely low runoff, which, in particular, can be seen from Table. 2. In the presence of powerful alluvium in winter, some rivers retain a subchannel flow, which is of great practical importance. In some cases, the water supply of settlements is based on it. The ice regime of the rivers of the Far East Territory is characterized by the annual formation of freeze-up lasting about 6 months. The rivers freeze at the beginning of November and open at the end of April, and in the lower reaches of the Amur - at the beginning of May.
With a long severe and little snowy winter, the thickness of ice on the rivers of the Far East is very significant; ice formation is observed, especially in the Shilka and Zeya basins. Spring ice drift is sometimes accompanied by powerful ice jams. There are frequent cases, mainly on small rivers, when water flows over ice in spring.
The rivers of Primorye are significantly distinguished by their ice regime. Here, in conditions of a warmer and milder climate, freeze-up is more short-lived, and in the southernmost part of Primorye it is unstable.
