On the issue of creating information support for assessing climate-related changes in the frequency of dangerous and adverse hydrological phenomena on rivers

V.A. Semenov, G.L. Kobozeva, A.A. Korshunov, A.A. Volkov, S.I. Shamin

Introduction

Among the dangerous hydrometeorological phenomena, the frequency and duration of which, with modern climate changes, changes mainly upwards, include floods and floods, ice jams, ice jams, water surges in sea estuaries, mudflows in mountainous areas, and the most unfavorable for water consumption and water use , the existence of aquatic ecosystems are low water in low water.

The main sources of information on the basis of which it is possible to assess the direction of changes in dangerous and adverse hydrological phenomena are the results of stationary observations of the hydrological regime of the rivers of Roshydromet and official information on natural phenomena that caused economic and social damage, provided to Roshydromet by the authorities of the constituent entities of the Russian Federation, the territories of which were affected by hazardous phenomena, as well as information from the Russian Emergencies Ministry. But, despite the scientific and practical importance of information about floods, mudflows and other dangerous hydrological phenomena, there is no systematized information about them not in databases, not in regulated publications. Information about floods and mudflows is not given in the materials of the state water cadastre, and only materials on extreme values ​​of the hydrological regime of rivers in hydrological yearbooks and specialized arrays presented in the State Fund database and the data bank “Hydrology - Rivers and Canals” State Institution “VNIIGMI-WDC”. Information about dangerous and unfavorable phenomena on the rivers that caused damage is not systematized and generalized, which makes it difficult to use them.

This article describes possible methodological approaches to the composition of the information of the database being created on hazardous and adverse hydrological phenomena that caused economic damage, the proposed forms and types of generalization of this information, software tools for maintaining the database and obtaining generalized materials for consumer services on its basis.

Composition, technology for creating, maintaining a database of information on hazardous and adverse hydrological phenomena

Information about the damage caused by hydrological phenomena to the population and sectors of the economy should be collected in the database “Hydrology Damage” (DB “Hydrodamage”) and entered into it for replenishment as they are recorded by Roshydromet divisions in the constituent entities of the Russian Federation and transferred to the State Institution “VNIIGMI-WDC” . Such information has already been accumulated at VNIIGMI-WDC since 1991.

The initial data for the database "Gidroshcheb" are provided in WORD in the form of tables containing descriptions of phenomena. An example of the composition of information is given in Table 1.

Table 1. Information on hazardous hydrological phenomena in May 2008 that caused damage to the population

№№ pp	the date	Territory	Brief OH characteristic	Lead time	Brief description of the damage caused to the national economy
		Republic of Buryatia (near Ulan-Ude)	Low water	month	The damage amounted to 19 million. 862 thousand rubles
	Within a month	Amur Region, Khabarovsk Territory	Low water	month	Difficulty of navigation
		Republic of Dagestan (Gumbetovsky district)	sel	Not provided.	Damaged housing construction, housing and communal services, drinking water intake facility, washed out local roads
		Republic of Dagestan (Kaitagsky district)	sel	1 day	In with. Guli water supply destroyed, 2 road bridges demolished, local roads damaged

The text of the presented descriptions (table of descriptions), as well as information about them in the form of codes (several tables) is entered into the database. All tables are interconnected and, upon request, you can get records, each of which contains the following elements:

Event start date (date format, i.e. in the form of 05/19/2008); Event end date;

Name (or code) of the subject; Name (or code) of the water body;

Name (or code) of the phenomenon; Predictability (predictability) of the phenomenon;

The number (persons) affected by the phenomenon (injured);

The number (persons) who died from the phenomenon; Description of damage;

List of subjects on whose territory it was observed

Phenomenon; Description of water bodies (list of river names).

For the convenience of entering into the database “Hydrodamage” and coding data, a screen form has been developed (Fig. 1).

Fig.1 Data entry form

For information about hazards for water bodies, a catalog of the distribution of rivers (groups of rivers) by large river basins and sea basins was prepared. The largest river basins(Rivers Volga, Ob, Yenisei, Lena, Amur) are divided into parts in the catalog (for example, in the Volga basin, the basin of the Kama river, the upper and lower Volga are distinguished, in the Ob basin, the rivers of the basin of the Irtysh and lower Ob rivers are distinguished, the upper Ob ). Each of the 17 groups of rivers has been assigned a code of water bodies (Table 2).

Table 2. Groups of water bodies in Russia

Group code	List of river basins of the group		group_name
1	Rivers Baltic Sea, Lake Ladoga and Onega, Rivers of Karelia and the Kola Peninsula		Northwest
2	Rivers Pechora, Northern Dvina, other rivers of the basins of the White and Barents Seas		northern edge
3	Upper and middle Ob		Ob upper
4	Lower Ob, Irtysh		Ob-Irtysh
5	Upper Yenisei basin		Yenisei upper
6	Lower Yenisei basin, Taimyr river		Lower Yenisei
7	Angara basin, Transbaikalia		Angara, Transbaikalia
8	Lena and river basins of the Laptev Sea basin		Lena
9	Basins of the Indigirka, Kolyma, and other rivers of the East Siberian Sea basin		Northeast
10	Rivers of the Kamchatka Territory		Kamchatka
11	Rivers of the Amur basin, Primorye, Sakhalin, rivers of the Sea of ​​Okhotsk basin		Far East
12	Upper Volga basin		Volga upper
13	Kama basin		Kama
14	Lower Volga Basin		Volga lower
15	Don basin, other rivers of the basin Sea of ​​Azov, the Dnieper basin		Azov-Black Sea
16	Kuban and Eastern Black Sea Basin		Kuban-Black Sea
17	Basins of the Terek, Ural, other rivers of the Caspian Sea		Caspian Sea

Obtaining generalized information about dangerous and adverse events

Relational database data can be accessed using Microsoft Access DBMS. By means of Access it is possible to select any combination of elements for a certain period or for a certain subject, water body, phenomenon. In addition to presenting data, it is possible to carry out various calculations.

An application was developed to work with the database using Access tools and the Visual Basic for Application language. Application software can calculate the distribution of the total duration of the phenomenon with the receipt of tables below 6 types.

1. Distribution of the duration of floods (during high waters, high waters, etc.), mudflows, low waters over the years for one river or a group of water bodies (one event each)

Name of the water body
	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	. . .
Water body1
Water body2
Water body3
. . .

X - the total number of days (duration) of the phenomenon, for one, several or all subjects (if this water body is on the territory of several subjects) per year.

2. Distribution of the duration of the event by months and water bodies (for a specific, selected event)

Name of the water body

Water body1

Water body2

Water body3

. . .

x is the total number of days of the duration of the phenomenon, for all subjects (if this water body is located on the territory of several subjects) for a long period.

Under the concept water body in this case, a group of rivers is understood, for example, the rivers of the Caspian Sea - one object, the lower Volga - one object.

3. By years and subjects (for a specific, selected phenomenon)

Subject name	Cumulative duration over years
	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	. . .
Subject1
Subject2
Subject3
. . .

X - the total number of days, the duration of the phenomenon per year, for all water bodies (if there are several water bodies on the territory of the subject).

4. By months and subjects (for a specific, selected phenomenon)

Subject name

Total duration per month

Subject1

Subject2

Subject3

. . .

x - the total number of days of the duration of the phenomenon for all rivers (if there are several rivers on the territory of the subject) for a long-term period for each month.

5 By water bodies for each event

Name water body	Phenomena
	high water	high water	Low water	Congestion	Zazhor	Surge phenomena	sat down
Water body1
Water body2
Water body3
. . .

X is the total number of days of the duration of the phenomenon in all subjects (if this water body is located on the territory of several subjects) for the selected period (several years or all years of observations).

6. By subjects for each of the phenomena

Subject name	Phenomena
	high water	high water	Low water	Congestion	Zazhor	Surge phenomena	Surge phenomena	sel	Landslides
Subject1
Subject2
Subject3

x is the total number of days of the duration of the phenomenon for all water bodies (if there are several water bodies on the territory of the subject) for the selected period (several years or the entire observation period).

In the application, the user is given the opportunity to select from a list of the following information: phenomena, groups of rivers, Federal District, time period (the year of the beginning of the period and the year of the end of the period).

All calculations are made taking into account the selected parameters. For example, for the analysis of dangerous floods in the Lower Yenisei for 2001-2005. the set of parameters to be selected will be as follows: the event is a flood, the group of rivers is the Yenisei (lower), the federal district is the Siberian Federal District, the start date of the period is 2001, the end date of the period is 2005.

As a result of a selection of information and calculations for the selected parameters, the distribution of the duration of the phenomenon by months (May-June) and water body looks like:

group of rivers	water body	4	5	6
Yenisei-nizhn	YENISEY (lower)
Yenisei-nizhn	Podkamennaya Tunguska
Yenisei-nizhn	Chunya
Yenisei-nizhn	Lower Tunguska

A screen form has been developed to work with the application software (Fig. 2).

Rice. 2 Form for data selection and calculations

A similar approach was used to create a database on dangerous meteorological phenomena (snowfalls, showers, etc.), which can serve as indicators of dangerous hydrological phenomena. This facilitates the task of their joint analysis and calculations.

The papers substantiate the need to combine into a single database information on dangerous meteorological phenomena based on observation data from the stationary meteorological network of Roshydromet and information about the phenomena that caused the confirmed damage. Such an association is also expedient for dangerous hydrological phenomena. To do this, from the materials of the stationary hydrological network, the unified database should include information on the height of the water level, at which water enters the floodplain and floods residential and utility buildings, roads, agricultural facilities, etc. Information on the maximum possible increases is also desirable. and lowering of the water level, levels limiting river transport, ecological well-being of the fauna of rivers, etc.

On the basis of the created database, the composition and forms of presentation and publication of information about hazardous and adverse hydrological phenomena will be developed.

Maintaining metadata catalogs

Considering that the task of improving information support on dangerous hydrological phenomena is a global one, it is advisable to take into account the possibility of international exchange of information on floods, floods, etc. when creating the database “Hydrodamage”. Therefore, when creating a database and metadata catalogs, it is advisable to use WMO-recommended information retrieval tools, for example, the ISO 19100 series of standards.

The set of standards in this series is like a single virtual model of geographic (spatial) information. Entities defined in one standard can easily be used in the model of another standardization area. The object-oriented approach to the description of the standard allows the use of inheritance, polymorphism and encapsulation when creating such models.

The ISO 19115 standard occupies one of the central places in the series. Since to describe spatial data it is necessary to indicate and describe all their properties and features,

defined in other standards of the 19100 series. Thus, ISO 19115, as it were, combines all other standards and uses their essence in its model.

The advantage of the ISO 19115 standard is that it is presented immediately in the Universal Modeling Language (UML), since UML diagrams can be directly used to generate a database schema in full accordance with this standard (see Fig. 3 and Fig. 4).

Fig.3 Information about metadata

With a large number of metadata elements provided by ISO 19115, there is a certain laboriousness in filling them out, but this task is solved both by the availability of publicly available tools for creating metadata and the metadata management wizard. For this purpose, the GeoNetWork project (Figure 5) is best suited, which uses ISO standards to create metadata catalogs ( ISO 19115, ISO 19139). The GeoNetWork system provides a multi-purpose infrastructure for accessing geoinformation resources, searching for the necessary data, and integrating information from various sources.

Rice. 4 Information about data dissemination.

The GeoNetWork system provides a multi-purpose infrastructure for accessing geoinformation resources, searching for the necessary data, and integrating information from various sources. These resources are accessible through a browser that allows you to connect to the servers included in the GeoNetWork system, which also has the following integrated functions and resources: a) Global Geospatial Data Library; b) A metadata catalog with a description of geospatial data, which provides users with convenient access to these data for further analysis; c) Search engine, tools for editing and preparing documents for printing; d) Means of integrating data from various sources.

Rice. 5 GeoNetWork main page

Metadata used in GeoNetWork includes information about the content of the desired information resource, for example, geographical position(Volga Upper); keyword (flood); the date; latitude-longitude. The metadata includes the type of geospatial information, the area of ​​distribution, images, etc., as well as information about the copyright for it (company, organization or individual), indicating restrictions on the possibility of using this information. In addition, this metadata contains information about the spatial, temporal and spectral resolution of the original data, as well as information about the original date systems and map projections. Information about the reliability, quality and completeness of the data is also available. Among the main properties of this software The following should be noted: a) Support for a variety of metadata standards, including ISO 19115 and 19139; b) Ability to set your own ISO 19115 profiles; c) Creation, editing, import of metadata elements; d) The ability to implement the search for metadata according to many criteria, including geospatial ones; e) The ability to support OGC CSW both as a client that collects information from other directories (harvesting), and as a server, which can be described by the above directory; f) Possibility of localization.

GeoNetWork can be integrated with many elements of the information infrastructure. The following databases can be used to store metadata: McKoi (used for debugging); MySQL; PostgreSQL Oracle. The application server into which GeoNetWork is integrated can be the freely distributed Jetty and Tomcat products, or the commercial IBM Websphere. This flexibility allows GeoNetWork to be integrated into existing information infrastructure.

Using the proposed conceptual approach to the creation of a metadata cataloging system, taking into account the world experience in building such systems and the described implementation in the GeoNetWork system, will significantly simplify the task of using the “Hydrodamage” database and disseminating information about hazardous and adverse hydrological phenomena.

BIBLIOGRAPHY

1. Assessment report on climate change and its consequences on the territory Russian Federation. Volume II. Consequences of climate change. Roshydromet, 2008. -288 p.

2. Korshunov A.A., Shaimardanov M.Z. Database of dangerous hydrometeorological phenomena.// Proceedings of VNIIGMI-WDC. – 2007.- Issue. 172. - P.132-139.

3. Bedritsky A.I., Korshunov A.A., Shaimardanov M.Z. Database of dangerous hydrometeorological phenomena in Russia and the results of statistical analysis. // Meteorology and Hydrology, 2009, No. 11. –S.5-14.

Lena river it is the largest Siberian river. By world standards, it is rather big. The Lena is the tenth longest river in the world. The length of the river, from source to mouth, is 4,400 km. The area of ​​the catchment basin is 2,490 thousand sq. km. The main food of the river comes from melt and rainwater. It flows through the territory of Yakutia in the Irkutsk region.

Where does it run: The source of the Lena River is located near Lake Baikal, on the Baikal Range. The height of the source above sea level is 1470 meters. It is from here, from a small swamp, that the most big river Siberia. In the upper course, the Lena flows through the mountainous Cis-Baikal and its channel is relatively narrow. The middle course is a segment between two tributaries: Vitim and Aldan. In the middle reaches, it is already a large full-flowing river, with a depth of up to 20 meters. Grow on both banks coniferous forests. After the city of Yakutsk, two more large tributaries flow into the river - Aldan and Vilyui. Lena turns into a truly gigantic stream. Its width is 10 km, and sometimes it spills over 30 km. Further, the riverbed is sandwiched between mountains and ridges, which do not allow it to overflow. At the mouth, the river forms a vast delta with many branches and flows into the Laptev Sea.

Characteristics of the Lena River.

The length of the river is 4400 km.

The catchment basin area is 2,490,000 sq. km.

The maximum width of the floodplain is 30 km.

Maximum depth - 21 m.

Fall - 1470 - 0 = 1470
Slope: 1470 divided by 4400 (fall per length)=0.33 m/km or 33 cm/km

Nutrition: the river is fed mainly by melt water, in the upper reaches - glacial nutrition.

Large tributaries: Olekma, Aldan, Vitim, Vilyui.

Biological resources, inhabitants: kondevka, nelma, omul, muksun, burbot, taimen. In the upper reaches there are: lenok, dace, pike, grayling, perch.

Freezing: late October, early November. Opening occurs in the upper reaches from late April to mid-May, in the lower reaches - in early June.

The regime of the river is characterized by spring floods and several high floods in summer. In autumn and winter - low water. Ice drift is often accompanied by ice jams and is characterized by great power.

Economic use of the Lena River.

Lena is one of the most clean rivers peace. The course of the river has not been changed by man. On the this moment no dams, hydroelectric power stations, or other structures have been built on the river. In uninhabited places, you can still drink water straight from the river.

Since there are not many settlements on the banks of the river, its economic use is not very intensive. This makes it possible to keep unique nature. As mentioned above, no dams, etc. have been built on the river, but Lena, nevertheless, is the main transport artery of Yakutia. Shipping starts from the Kachug pier. Unfortunately, before the confluence of the Vitim, the river is not navigable.

Major ports: Osetrovo, Kirensk, Lensk, Yakutsk

Environmental problems.

Scientists from the University of Alaska, the Permafrost Institute of the Russian Academy of Sciences, and the National French Center for Scientific Research have found that global warming has a negative impact on the river. In these parts in winter, the temperature drops to -70 degrees, and the permafrost is one and a half kilometers. Scientists have found that over the past 40 years the air temperature has risen by 4 degrees. Floods, already very strong, are only gaining strength every year, which destroys the banks of the river. Besides. the islands move down the river. In 2009, the speed of their descent reached 27 meters per year.

Lena- the largest river in Siberia, and throughout Russia, flows into the Laptev Sea. The tenth longest river in the world, flows through the territory of Yakutia, the Irkutsk region, part of its tributaries belong to the Krasnoyarsk, Khabarovsk, Trans-Baikal Territory and to the Republic of Buryatia. The length of the river, excluding tributaries, is 4,400 km, the basin area is 2,490 thousand km2. The main food is melted snow and rain water. You can read more about the Lena basin.

River flow

The source of the Lena is a small swamp located 12 kilometers from the Baikal Ridge. The upper course of the river falls on the mountainous Cis-Baikal region, here it is relatively narrow and not wide. The middle course is a segment between the Vitim and Aldan rivers. After the confluence of the Vitim, Lena becomes huge deep river with a depth of up to 20 meters, the valley widens up to 20 km. Dense coniferous forests grow on both sides. From Olekma to Aldan, not a single large tributary flows into the Lena, all these 500 km it flows in a narrow and deep valley. After the city of Pokrovsk, a sharp expansion of the valley occurs. After Yakutsk, two large tributaries flow into it - Aldan and Vilyui. Now it is a giant water stream up to 10 km wide, and in some places it spills up to 20-30 and up to 20 meters deep. In the lower reaches, the river is very narrow on all sides, mountains and ridges prevent it from overflowing. At the mouth, about 150 km from the sea, the vast Lena Delta begins.

Population

The banks of the Lena River are deserted, there are practically no settlements. A large number of settlements are observed only in the Yakutsk region. There are many abandoned villages and shift camps.

Most big cities this is:

• Ust-Kut
• Kirensk
• Lensk
• Olekminsk
• Pokrovsk
• Yakutsk
• Zhigansk

Shipping

Lena is one of the main transport arteries of Yakutia. In conditions of bad roads, waterways become very relevant. The main part of the "northern delivery" is produced along this river. Shipping starts from the Kachug pier. Unfortunately, below the settlement of Ust-Kut and before the confluence of the Vitim tributary with the Lena River, there are a lot of shallow and difficult areas for navigation. Every year, work is carried out to deepen the bed of the Lena.

The navigation period lasts from 125 to 170 days. The largest ports on the Lena:

• Osetrovo
• Kirensk
• Lensk
• Yakutsk

Channel change

Scientists from the National French Center for Scientific Research, as well as scientists from the Permafrost Institute of the Russian Academy of Sciences and the University of Alaska, have described and found that warming has a negative impact on the Lena River.
In this area, in winter, the temperature of the surrounding area drops to -70 degrees, the thickness of the permafrost reaches 1.5 km. Scientists have found that over the past forty years average temperature the air rose by four degrees, and the temperature of the soil by one degree Celsius. Water temperatures in spring and summer rose by two degrees.
Every year the flood becomes more and more powerful, plus, during the ice drift, the shores are subjected to very strong thermal and mechanical stress and, as a result, are destroyed. In addition, due to accelerating erosion processes, the islands, consisting mainly of silt and sand, are gradually moving towards the lower reaches of the river. In 2009 average speed migration of the islands has reached 27 meters per year.

The main tributaries of the Lena

• Aldan
• Olekma
• Vilyuy
• Kirenga
• Young
• Tuolba
• Buotama
• Blue

The largest of them is the Aldan and Vitim rivers.

Briefly

• Researchers suggest that the name of the river comes from the Tungus-Manchurian "Yelyu-Ene", which translates as "big river"
• The river was discovered by the Russians in 1619-1623, by the explorer Pyanda
• Lena is the main transport artery of Yakutia
• because of global warming Lena changes course.
• Lena is the 10th longest among all the rivers of the world, with a length of 4400 km.
• On a part of the right bank of the river there is a national natural Park Lena Pillars

The main characteristics of the Lena River:

• The length of the River is 4400 km.
• Basin area - 2,490 thousand km2
• The maximum width of the floodplain is 30 km.
• The maximum depth is 21 m.

1. What is the water content of a river? What indicators characterize it?

The water content (water content) of a river is the amount of water carried by a certain river during the year. Average multi-year volume annual runoff serves as an indicator (index) of the water content of the river. The concept of "water content" is usually used to compare the average water flow of different rivers.

2. Give definitions of water consumption and annual runoff.

Water flow (in a watercourse) is the volume of water (liquid) flowing through the cross section of a watercourse per unit of time. Measured in flow units (m³/s). Annual runoff is the total volume of water that flows in a year, usually referred to the outlet of a catchment or river basin.

3. What is the fall and slope of the river? What do they depend on?

The fall of the river is the difference in elevations of the water surface at the source and mouth of the river or in a separate section of it. River slope - the ratio of the fall of a river (or other watercourse) in any of its sections to the length of this section. The slope of a river is expressed as a ppm or percentage, as well as the magnitude of the fall per section length. Both of these concepts depend on the terrain, the steeper the terrain, the greater the slope and fall of the river.

4. Choose the correct answer. The river is predominantly rain fed: a) Amur; b) Yenisei; c) Lena; d) Terek.

5. Choose the correct answer. Depends on the climate: a) the speed of the current; b) river regime; c) direction of flow.

6. Choose the correct answers. The rivers of Russia belong to the basin: a) indian ocean; b) Pacific Ocean; c) the Arctic Ocean; G) Atlantic Ocean; e) internal flow.

Answer: B, C, D.

7. List the features of the rivers of Russia.

The rivers of Russia are characterized by two distinctive features nutrition: 1) due to the position of the country in temperate and high latitudes and the continentality of the climate, snow cover almost everywhere takes part in the nutrition of rivers; 2) most rivers are characterized by three sources of nutrition: melted snow, rain and groundwater. A significantly smaller number of rivers have either all four sources of supply, or two in various combinations (snow + rain, snow + ground, rain + ground).

9. To determine the fall of the river, it is necessary to calculate the difference between the height of its source and the height of the mouth. The rivers flowing into the sea have a mouth height of 0 m (with the exception of the Caspian Sea-lake, where the mouths of the rivers lie at a height of -27 m). If a river flows into a lake, then the level of the surface of the water in the lake is the height of its mouth. If the river flows out of the lake (for example, the Angara from Lake Baikal), then the height of the source is the level of the water surface in the lake. Calculate the fall of the rivers Pechora (source height 676 m), Kama (source height 331 m, mouth height 36 m).

Pechora source - 676m, mouth - 0m we measure the fall: fall = source-mouth: 676-0=630m. Kama: source - 331m, mouth - 36m: fall = source-mouth: 331-36=295m.

10. Using the thematic maps of the atlas, characterize one of Russian rivers(optional) according to the plan: a) geographic location; b) length, height of the source and mouth; c) nutrition and regimen; d) adverse events on the river and their causes; e) economic use.

Characteristics of the Volga River:

A) The river is located in the European part of Russia, one of largest rivers on Earth and the largest in Europe. The Volga originates on the Valdai Upland, flows into the Caspian Sea.

B) Length - 3530 km. The source is at an altitude of 229 m, the mouth lies 28 m below sea level.

C) The Volga is mainly fed by snow (60% of annual runoff), ground (30%) and rain (10%) waters. The natural regime is characterized by spring floods (April - June), low water levels during the summer and winter low water periods, and autumn rain floods (October).

D) In ​​the water area of ​​the river, there is a sea of ​​fish, overgrowing of the reservoir, as a result of which the river becomes shallower, less navigable and polluted. Also, every spring there is a flood of water in the river - floods as a result of the flood.

E) Oil, oil products, salt, gravel, coal, bread, cement, metal, vegetables, fish, etc. are supplied up the Volga; down - timber, lumber, mineral building materials, industrial materials. Down the Kama - coal, timber, lumber, sulfur pyrites, metals, chemical cargoes, mineral building materials, oil, oil products; up - salt, vegetables, industrial and food products.

The Lena River is the largest river in North-Eastern Siberia, flows into the Laptev Sea. The tenth longest river in the world and the eighth largest river in the world, flows through the territory of the Irkutsk region and Yakutia, some of its tributaries belong to the Transbaikal, Krasnoyarsk, Khabarovsk Territory and to the Republic of Buryatia. The Lena is the largest of the Russian rivers, whose basin lies entirely within the country. It freezes in the reverse order of opening - from the lower reaches to the upper reaches. Geographical position According to the nature of the river flow, three of its sections are distinguished: from the source to the mouth of the Vitim; from the mouth of the Vitim to the confluence of the Aldan and the third lower section - from the confluence of the Aldan to the mouth.

The source of Lena is a small lake 12 kilometers from Baikal, located at an altitude of 1470 meters. On August 19, 1997, a chapel with a commemorative plaque was installed at the source. The entire upper course of the Lena to the confluence of the Vitim, that is, almost a third of its length, falls on the mountainous Cis-Baikal region. Water consumption in the Kirensk region is 1100 m 3 / sec. The middle course includes its segment between the mouths of the Vitim and Aldan rivers, 1415 km long. Near the confluence of the Vitim, the Lena enters Yakutia and flows through it to the very mouth. Having accepted Vitim, Lena turns into a very large deep river. Depths increase to 10-12 m, the channel expands, and numerous islands appear in it, the valley expands to 20-30 km. The valley is asymmetrical: the left slope is flatter; the right one, represented by the northern edge of the Patom Highlands, is steeper and higher. On both slopes dense coniferous forests grow, only occasionally replaced by meadows. From the Olekma to the Aldan, the Lena does not have a single significant tributary. For more than 500 km, the Lena flows in a deep and narrow valley cut into limestone. Below the city of Pokrovsk, there is a sharp expansion of the Lena valley. The flow velocity slows down strongly, it nowhere exceeds 1.3 m/s, and for the most part drops to 0.5-0.7 m/s. Only the floodplain has a width of five - seven, and in some places even 15 km, and the entire valley has a width of 20 or more kilometers. Below Yakutsk, the Lena receives its two main tributaries - Aldan and Vilyuy. Now it is a giant water stream; even where it flows in one channel, its width reaches 10 km, and its depth exceeds 16-20 m. Where there are many islands, the Lena spills over 20-30 km. The banks of the river are harsh and deserted. Settlements very rare. In the lower reaches of the Lena, its basin is very narrow: from the east, the spurs of the Verkhoyansk Range, the watershed of the Lena and Yana rivers, advance; from the west, insignificant uplands of the Central Siberian Plateau separate the basins of the Lena and the Olenyok River. Below the village of Bulun, the river is squeezed by the Kharaulakh ridges coming very close to it from the east and Chekanovsky from the west. Approximately 150 km from the sea, the vast Lena Delta begins.

river hydrology The length of the river is 4400 km, the basin area is 2490 thousand km 2. The main food, as well as almost all tributaries, is snowmelt and rainwater. The widespread distribution of permafrost prevents the supply of rivers with groundwater, with the only exception being geothermal sources. In connection with the general precipitation regime, the Lena is characterized by spring floods, several rather high floods in summer, and low autumn-winter low water up to 366 m 3 /s at the mouth. The spring ice drift is very powerful and is often accompanied by ice jams. The highest average monthly water discharge at the mouth was observed in June 1989 and amounted to 104,000 m 3 /s, the maximum water discharge at the mouth during a flood can exceed 250,000 m 3 /s. Hydrological data on water discharge at the mouth of the Lena in different sources contradict each other and often contain errors. The river is characterized by periodic significant increases in annual flow, which do not occur due to a large number precipitation in the basin, and primarily due to the intensive melting of ice and permafrost in the lower part of the basin. Such phenomena take place during warm years in the north of Yakutia and lead to a significant increase in runoff. So, for example, in 1989 the average annual water discharge was 23,624 m 3 /s, which corresponds to 744 km 3 per year. For 67 years of observations at the Kyusyur station near the mouth, the average annual water discharge is 17,175 m 3 /s or 541 km 3 per year, had a minimum value in 1986 - 13,044 m 3 /s.

First of all, at the end of April, the spring flood begins in the Kirensk region - on the upper Lena - and, gradually moving north, advancing on the still ice-bound river, reaches the lower reaches in mid-June. Water rises during the spill to 6-8 m above the low-water level. In the lower reaches, the water rise reaches 10 m. In the wide expanses of the Lena and in places where it narrows, the ice drift is menacing and beautiful. Major tributaries Lenas significantly increase its water content, but, in general, the increase in costs occurs from top to bottom rather evenly. Economic use Lena to this day remains the main transport artery of Yakutia, connecting its regions with the federal transport infrastructure. The main part of the "northern delivery" is produced along the Lena. The Kachug pier is considered to be the beginning of navigation, however, only small vessels pass through it upstream from the port of Osetrov. Below the city of Ust-Kut, up to the confluence of the Vitim tributary, on the Lena there are still many sections difficult for navigation and relatively shallow places, forcing to carry out work to deepen the bottom every year. The navigation period lasts from 125 to 170 days.