Lena is the largest river in Siberia. She is rather big by world standards. In the list of the longest rivers of our planet, it takes tenth place. Lena is four thousand four hundred kilometers long. The catchment basin is located on an area of almost two and a half thousand square kilometers. A majestic river flows through the territory of the Irkutsk region and Yakutia.
Geographical position
The upper reaches of the river, as well as significant areas of basins related to its right tributaries, are located in the mountainous regions of Transbaikalia, Pribaikalye, and also on the Aldan Highlands. In the region of the Central Siberian Plateau there is a large part of its left-bank basin. The lowest section runs along the Central Yakut Lowland.
Division
In the channel of the Lena River , there are three main sections. The first one is the top one. It passes from the source to the place of its confluence with the Vitim River. The middle section ends where Lena meets with the river. Aldan. In the third, lower section, the river carries its waters to the mouth.
In the upper reaches, the Lena regime is stormy and fast. In this zone there are all the signs characteristic of mountain rivers. The flow of water is rapid, and the channel is winding. Many places have rapids. At the same time, the shores are rocky and high. In the upper reaches, the water stream foams and boils, rapidly moving to the north.
The wayward and mighty river regime changes on the way to Kirensk. Here Lena takes the waters of its tributary of the river. Kirengi and calms a little. Its channel becomes wider and deeper (in some places this value is equal to ten meters). The rocky shores recede. Stones are replaced by mighty cedars and tall pines, spruce and fir. Larch also grows here.
The river gains even greater power after Olekma flows into it - its right tributary. Further to Aldan, Lena flows along the Prilensky plateau. Here its shores have peculiar and extremely steep slopes.
The middle course ends after Lena meets her right tributary, Aldan. At this point, the great river of Siberia forms numerous channels with small islands.
In the lower reaches Lena is spreading in all its breadth. In these places, she shows all the power and greatness of the Siberian river, which cannot but arouse admiration and delight.
Food
The river receives fifty percent of its annual runoff from melting snow cover, as well as rainfall. Additional sources of nutrition for the Lena River are groundwater. From them she receives one or two percent of her runoff. Thus, the type of nutrition of the Lena River is mixed. But not only the listed sources increase the flow of the majestic Siberian beauty.
The power sources of the Lena River are also all its tributaries. This list includes Aldan and Chaya, Vitin and Olekma, Kuta and Vilyui, Kirenga and Molodo, Chuya and Tuolba, Buotama and Sinaya. Tributaries have various sizes. The largest of them are the Vitim and Aldan rivers.
The nutrition of the tributaries consists mainly of the waters formed as a result of snowmelt, as well as precipitation. Some runoff also comes from subsoil. However, its volume is very small, since there is a permafrost zone on the territory of the river flow. The exception is only those areas where geothermal sources are located.
Thus, the type of nutrition of the Lena River and its tributaries is the same. Moreover, it belongs to the form of mixed.
The nutrition and regime of the Lena River are closely interconnected. Moreover, they are dependent on the general precipitation regime. The mouth of the Lena is characterized by extensive spring flood. The river spills in the summer. At this time, high floods are observed several times there. But the autumn-winter low water at the mouth is low.
The nutrition and regime of the Lena River changes dramatically in the spring. During this period, a powerful ice drift is observed and snow cover is melting. During a flood, water flow in the estuary can be higher than 250,000 cubic meters per second.
Water availability
The water regime of the Lena River is characterized by high floods. In the spring, a change in the water level occurs on average by ten to fifteen meters. In the lower reaches this value reaches eighteen meters. The regime of the Lena River in summer depends on the amount of precipitation. In this case, rain floods are observed several times. A small runoff is typical for winter.
Lena is in second place in terms of water availability among Russian rivers. In terms of its flow, it is second only to the Yenisei.
The regime of the Lena River is characterized by an average annual discharge at the mouth equal to seventeen thousand cubic meters per second. At the same time, the maximum figure is 200,000, and the minimum is 366.
The type of water regime of the Lena River is preserved throughout its length. However, despite this, in different areas, the indicators of water consumption have their own values. So, above the mouth of the Kirenga River, the average annual water discharge is at around 480 cubic meters per second. At the confluence of the Lena River. Vitim, this value is 1700. At the mouths of Olekma, Aldan and Vilyuy, respectively, 4500, 6800 and 12 100 cubic meters per second. But in the Laptev Sea, where Lena carries its waters, the annual runoff is about five hundred and forty cubic kilometers.
Suspend
Together with the waters of the Lena River, forty-one million tons of various solutes enter the Laptev Sea annually. Suspended sediments are also carried out. About 12 million tons of them fall into the sea during the year. Turbidity of water is in the range of 50-60 grams per cubic meter. But the mineralization index is 80-100 milligrams per liter.
Icing
During the cold periods of the year, a drop is observed in water level indicators, and the regime of the Lena River changes dramatically. During this period, its surface is icebound. The river freely carries its waters for five to six months during the year in the south and four to five months in the north. In the tributaries of the Lena, ice formation is established a little earlier. The river itself is frozen down ten days later.
Ledostav in the upper reaches is set in late October. In the lower - a month earlier. Opening of ice can drag in the upper reaches until mid-May, and in the lower reaches until early June.
The regime of the Lena River changes dramatically during the spring ice drift. During this period, congestion occurs that significantly raises the water level.
Thermal mode
The water temperature indicators along the entire length of the Lena River have significant differences. Monthly average indicators in the zones of the upper and middle reaches are at around nineteen. But in the cold periods (from November to April), the water temperature is on average zero.
As for the lower reaches of the river, here the average monthly values are slightly lower. In the warmer months, they do not exceed seventeen degrees. The period with a zero mark lasts much longer. It starts in October and ends in May.
The temperature regime of the Lena River in the upper part of its delta has minimal values. In this regard, the longest period of ice water cover is observed in this zone.
The spring flood on the Lena River lasts an average of thirty-five days. Moreover, in the upper reaches this period is the least long. It is twenty seven days. In the lower reaches of the river, spring flood can last up to forty-four days.
Environmental problems
Global warming, which in recent years has been observed on our planet, has a negative impact on the river. In the territory where it flows, over the past forty years there has been a rise in annual air temperature by four degrees. In this regard, spring floods become much more powerful. This destroys the banks of the river. In addition, the islands move along the river. Already in 2009, the speed of their descent was recorded, which amounted to twenty-seven meters per year.
Economic use
Lena is one of the cleanest rivers on our planet. In addition, its channel was not changed by man. Currently, no dams, hydroelectric power stations, or other waterworks have been built on the Lena River. In places located far from settlements, the water is so clean that it can be drunk directly from the river.
As you can see, the unique nature of these places is practically preserved. This is due to the fact that the economic use of the Lena River is not very intensive. This factor is affected by the lack of a large number of settlements, as well as various hydraulic structures. Despite this, Lena serves as the main transport artery located in Yakutia. It is navigable from the tributary of Kachug to its mouth. The channel to Ust-Kut can only pass vessels with a slight draft. The navigation period lasts in the upper river about one hundred and sixty days, and in its lower river - one hundred and twenty. The main marinas are Yakutsk and Zhigansk, Vitim and Lenek, Budun and Kirensk, Kachug and Zhigalovo, Olekminsk and Osetrovo. Navigable and some tributaries of the Lena. Among them are Vitim and Olekma, Kirenga and Vilyuy, as well as Aldan.
In the Lena River basin , mining is carried out. Gold-bearing areas and diamond deposits were found in this territory. The Lena basin is rich in rock salt and iron ore, mica and natural gas. In the lower reaches of the river developed fishing. Burbot and omul, Siberian vendace and muksun are found here.