What is the river, everyone knows.This body of water, which originates as a rule, in the mountains or on the hills, and, having made a journey of tens to hundreds of kilometers, flows into the reservoir, lake or sea.That part of the river, which flows from the main channel, called sleeve.A plot with a fast-flowing, running along the mountain slopes - the threshold.So what does is the river?Which components can divide it?Let's look in more detail what we mean by such a simple and familiar words as "river".
What is a river?
first basic knowledge of the animate and inanimate nature we have in the school at the lessons of the world.Students are introduced to concepts such as a stream, river, lake, sea, ocean, and so on.Of course, the teacher can not tell what part of the river there.2 class - it's too early to memorize a set of terms and concepts.Therefore, children turn to their parents.And I must say, put them in a dead end.Because adults often can not answer such simple questions.So, not all will be able to explain the difference between the delta of the river bed, or oxbow lakes are formed.Or here's another example - that this river valley?Let's re-examine all of these concepts.
River - a permanent water flow.In arid regions of the world, such as Africa and Australia, it may temporarily dry up.They feed on the river snow, groundwater, rain and glacial waters.This natural body of water has for centuries developed its drain channel.And the relationship of climate and the river is very clear.And it is easy to trace.From climate depends on the flow regime: it is not the same in different altitude, longitude and latitude zones.
features we are considering water resources also depends on the terrain and the area in which it is located.Map of rivers shows that they can pass through the plain, down the mountain slopes.They can be detected even underground.Plain of the river flow through the flat wide area.It is dominated by the coast of washouts, ie lateral erosion.The slopes are gentle pond, stream, usually winding, for a weakly pronounced.Most other characteristics of the mountain rivers.The bed of their very narrow and rocky.Valley of poorly designed, with steep slopes, beaches.Typically, these waterways are not deep, but the rate of flow is enormous.
also vary lake river.They can either flow from the lakes, or to pave the way through them.These objects are characterized by higher runoff in low water.At the lake the river a long period of high water.As a rule, they are not too long.Several other marshy river.There are, of course, at least.They have a sprawling high water, frequent floods due to the characteristic of the flat terrain, where the channel, which is constantly replenished with water slowly out of the swamp.
Particularly noteworthy karst river.They feed almost always of groundwater that fill the so-called karst cavities.Low water flow in these rivers increased.
Source of the river
Start river called the source.This place, where a continuous stream.The source may be different: a stream, lake, swamp.Getting large rivers often provide several smaller ponds.This source will be the place of their merger.For example, the beginning of the Ob River provide water Katun and Biya.Mountain streams are almost always formed from the merger of the plurality of streams.But the plain begin their journey from the lake.It is worth remembering that the geography of each individual reservoir.And the source of each river also is unique.
before disassembling the names of parts of the river, you need to stop on such terms as "river valley".Speaking the language of science, we are talking about the elongated recesses created by watercourses.They have a definite bias towards the current.All parameters of river valleys (width, depth and complexity of the structure) are completely dependent on the degree of power the watercourse.Values have the duration of its existence, the nature of the surrounding terrain.Taken into account the stability of the rock and the degree of tectonic activity area.
all river valleys are the bottom plains and hills.But, again, their characteristics depend on the topography of the territory.Mountain rivers are distinguished by steep slopes.They are deeper than the plains.In this valley they are not wide, but narrow.Often, they have revealed a stepped bottom.The flat valleys are quite different.They consist of pitted oxbows and floodplains bed.Young Valley characterized by steep slopes and older have stepped shore.Such slopes are called terraces.The older the river, so it stepped coast more and more widely.
Young river terraces do not have.Even floodplain it does not occur everywhere.The bottom of the trough-shaped such reservoirs, this is often due to the fact that this territory formerly held the glacier.But there are exceptions.
main part of the river - the channel and floodplain - are formed in different ways.In compliant to the rapid erosion of the rocks are much wider than in crystal soil.Also, the main feature of the river valleys is that they are always gradually expand to the mouths.Their slopes are more gentle and terraces - advanced.
Have river valleys and a special practical significance.This is the most convenient place for the construction of settlements.As a rule, the terraces are cities and towns, and floodplains are excellent land for grazing.
If translated literally, "floodplain" - is something that is filled with water.And it is absolutely correct definition.It's part of the river valley, which during floods and flood completely filled with water.The floodplain has its own unique landscape.Often it is divided into two levels.Lower floodplain filled regularly from year to year.The upper part - only in those years when there is a high water level.
Each flooding leaves its imprint on the floodplain.It erodes the surface of the soil, creating gullies and forms oxbows.Every year the earth's surface is sand, gravel and loam.This leads to an increase in the level of the floodplain.At the same time the process of deepening the channel.Over time, the low floodplain becomes high, formed above the floodplain terraces.They have stepped character.The floodplain has coastal cliffs several meters high.Often it formed gullies and oxbows.
have extensive flood plains of rivers.For example, Ob width is 30 km, and in some areas and more.Mountain river floodplains can not boast.Such sites found only fragments, wherein they can be detected from one side or the other.
value of wetlands is large.Such valuable land used as pasture and hay meadows.Floodplain virtually every major river in the area of steppe, forest, or taiga - is a stable area for livestock.
The lowest part of the river, or rather the valley, called the track.It formed a continuous water stream.According to him constantly moving flow and most of the bottom sediments.The bed typically has a plurality of branches.It is rarely straightforward, except that of mountain streams.
Riverbed, as we approach the mouth, forms a plurality of channels and sleeves.Especially a lot of them in the Delta.Duct is formed in the floodplain during periods of high water, but in the hot summer months it may dry up.Sleeves lowland rivers are tortuous terrain.They celebrated fine-clastic sediment accumulation moving.In mountain rivers ducts are formed very rarely, and the sleeves are more direct.Often you can find areas of rapids and waterfalls of varying heights.They may be encumbered with gravel and large boulders.Ples - deep section of the sleeve - alternate with shoals.Often such transitions are observed in the lower reaches.The width of the sleeves have large rivers, for example, such as the Yenisey, Lena, Volga, Ob, can reach several tens of kilometers.
The river often forms rapids.Most often they are found in the bed of a mountain river.Threshold - is the shallow, covered with pebbles and boulders.It is formed in the places where it is difficult to overlie eroded rocks.There are marked differences of large currents.Thresholds, because of its topography, make it impossible to shipping and make it very difficult alloy.Sometimes because people are forced to build a bypass channels.Often downstream of the rapids erect hydroelectric power plants.This is used to best advantage and significant fall in the river slopes.One example is the Ust-Ilim hydroelectric station on the Angara River.
What is Delta?
Delta - a lowland river.It is almost always characterized by numerous branched ducts and sleeves.Formed in the lower reaches of the delta only.It is also important to note that this section of the reservoir formed by a special mini-ecosystem.Every river it unique.
Most of the major rivers of Russia has a vast delta with a well-developed alluvial activity.As classic examples always lead the Volga and Lena.Their huge delta and branch into a network of hoses.In addition they can also note the Kuban, Terek and the Neva River.A distinctive feature of the delta, located in the southern regions, marshes are developed.It noted riotous diversity of the vegetation along the banks find shelter various mammals, amphibians and reptiles.Many species of birds build their forests and thickets near water their nests.But these sites are particularly valuable fisheries resources.Noting the question of what the Delta, it's safe to say that this is a unique microcosm with its nature.
When the river flows into the sea are often formed shallow bays.They are called estuaries.Such Bay in the lower reaches of the river - the place is very unusual and picturesque.Lyman occurs when flooding lowland rivers sea.It can be opened - then it is called guboyu.This Gulf did not have to be connected to the sea.There are indoor and estuaries, t. E. Separated from seawater strip of land - a narrow spit.Typically, salt water estuaries, but not to the extent as the sea.However, with a small inflow of fresh water, it can be very saline.The bay is formed in the lower reaches of the river is not always.A lot of them is located on the coast of the Azov Sea.Estuaries have rivers Dniester and Kuban.
place where the river flows into the lake, pond, sea or other body of water called the mouth.It can be different.For example, in the area adjacent to the mouth, can be formed estuary, bay or wide delta.But the river water can disappear for several reasons - the fence for irrigation of agricultural plantations, or simply evaporate.In this case we speak of the mouth of the blind, that is, the river flows into nowhere.It often happens that at the end of the way the water just go into the ground, and the stream disappears.Therefore, we can not say that each has a clearly defined river estuary.For example, the channel of the river is lost in the swamps of the Okavango in the Kalahari Desert.Thus, the source of the river and the mouth is not necessarily clearly expressed, and detect them is not always possible.
tributary of the
influx - it streams which flow into a larger river.From the latter, it is usually characterized by smaller volumes of water and length.But, as shown by studies carried out in recent decades, it is not always the case.There are several rivers that violate the established law.For example, the Oka flows into the Volga, which gives it the volume of water.Thus in this great waterway flows and Kama, which is also more affluent.But on the Volga all the known exceptions do not end there.Angara tributary of the Yenisei recognized.Thus the portion of the river, which merges with the second object, has double the amount of water.That is, we can say that the larger the Angara.As a general rule, the influx of a difference in the direction of the valley, so you can determine exactly what falls into that.
But the river is not always coalesce.They sometimes fall into a lake or other water bodies.Tributaries divided into right and left, depending on which side they are suitable for the channel.They come in a different order: primary and secondary.Some of them fall directly into the main drainage channel.It is the primary tributaries.All the rivers that connect them, are secondary.For example, Zhizdra is paramount for the influx of the Oka and Volga for the secondary.
sleeve - it is also a part of the river.This may be a branch or "splitting" of the channel.Note that the sleeve must fall back into the river.Sometimes it takes a few tens of meters, but often extends for several kilometers.The sleeve is formed as a result of sedimentation.In the line formed by the island.The sleeves have many local names.On the Volga they are called "Volozhka."On the river Northern Dvina they represent the word "hollow."On the Don locals call them starodone.On the Danube River - "Arm".The sleeves may be of secondary importance.Then they are usually called channels.Almost all the hoses and ducts after some time become oxbow lakes.As the mainstream of change, they are disconnected.
Staritsa Staritsa - is an elongated section of the river or lake, disconnect from the mainstream.Starkey can be found in the flood plain or on the lower terrace.They arise due to the overlapping of clay or sandy shoals sleeves, as well as in breaking the necks of meanders.In older women always characteristic horseshoe shape.They are connected to the water main channel only at the time of the spill.However, most of the time they are separate reservoirs.They are often called floodplain lakes.The scheme of the river on which are marked all the older women, can give an idea about how to track looked before.Over time, this object is changed - it grows, it is changing shape.Starica turns in the Wetlands, and then completely in the damp meadow.After some time of her no trace remains.
river level river level - the height of the water surface.This term is used for almost all natural and artificial reservoirs.Every river has a low and high values mentioned.The maximum water level is marked at the time of the flood, usually in the spring and summer.Autumn floods also occur.The reason for that are the lingering rain showers.In winter, the water level drops to the minimum level.Often, the river becomes less affluent and summer - during long droughts when the streams that flow into the riverbed, dry.Mode of each river is strictly individual.The reduction and increase in water level is always dependent on the climatic and relief features.