Powerful mountain systems of Tajikistan and branches share the territory of the republic for several hydrographic areas, forming two major river systems – the Amu Darya and Syr Darya rivers. The northern regions of Tajikistan took part in the Syrdarya river basin during the middle of her, an area of 13.4 thousand sq.km. This is the tenth part of the area of the country.
Almost all the rest of the country is located in the Amu Darya basin, separated by mountain ranges on the major river basins, watersheds differing height, degree of glaciation, the different development of the river network, the terms of the power of rivers and watersheds. Only the North East Pamir refers to the inland areas (pools of Lake Karakul and Markansu river).
Hydrographic network of Tajikistan make up more than 25 thousand rivers with a total length of 69.2 thousand. Km. Of these rivers 947 have a length of 10 to 100 km, 16 rivers – from 100 to 500 km long and 4 river 500 km (Map 1). Geographically river network is divided into large pools Zarafshan river, Surkhandarya (Karatag river Sherkent) Kafirnigan, Vakhsh, Panj (Gunt, Bartang, Yazgulem, Vanj, Kyzylsu-south) The largest republic of the river: the river Panj, 521 km, Vakhsh river, 524 km, the river Bartang 528-km river Kafirnigan 387-km river Zarafshan-310 km. (Total length 877 km), the Syr Darya River in the republic has a length of 180 km.
The average river flow of 56.2 cubic meters. km. The main source of water is seasonal snow. On southern slopes of Hissar, Karategin and Alay ranges falls to 2000 mm of rainfall per year mainly in the form of snow, which melts the end of June. In the highlands, where the summers are short and cool, fresh snow does not have time to melt accumulates, gradually turning into ice. Since glaciers are formed, whose role in feeding the rivers of Tajikistan is very high, as they give each year in mid-summer to 13 cubic kilometers of water. Most of the rivers of our country originate from glaciers. By Type Power Tajikistan’s rivers can be divided into four types.
Map of Tajikistan rivers
Power-glacial snow. Flood lasts up to seven months of the year, the highest costs in July and August. It is almost all the major rivers of the country: Vanj, Panj, Zarafshan. Eating snow and glaciers. Flood lasts up to six months, the highest costs in May or June. It Karatag Kafirnigan and its tributaries, including the Varzob, on the banks of which stands the capital of the republic.
Eating snow. Flood lasts four to six months, the highest costs in April or May. It pritokiKafirnigana, Varzob – Luchob, Kharangon and others. Eating snow-rain usually in rivers, swimming pools which are located in the midlands. Flood lasts about four months, its peak – in April. These rivers are Kyzylsu-south, Yakhsu, Tairsu.
Karatag River in the western part of Tajikistan
Thus, one of the main differences of our mountain rivers of the plains is long and stormy flood, during which the rivers pass 70 – 90% of annual runoff.
Tajikistan has a very high water availability. The average runoff per square kilometer is 354 thousand cubic meters per year – four times more than the average for the entire Central Asia region.
In the season of flood rivers carry a large amount of suspended sediment, which increase erosion activity of water. For example, Kafirnigan moves for a year about 10 million tons of sediment and Kyzylsu-South – more than 15 million tons. As a result, in one place shore washed away, in the other – there are shoals and islands. Therefore, every year these rivers have to spend costly bank protection works.
Cir River (in northern Tajikistan)
Tajikistan’s rivers are not only a source of moisture, without which the country would become a desert. As a potential hydropower reserves in the CIS Tajikistan ranks second after Russia. Only the major rivers of the republic and their tributaries can produce up to 300 billion kilowatt / hours of electricity per year. On the Vakhsh already has five hydroelectric power plants, including the largest in Central Asia, the Nurek hydropower plant ZA million kilowatts. Overall, Vakhsh can rotate the turbine cascade hydropower plants with total capacity of 8 million kilowatts, and the Panj – twice.
The first hydrometric stations were set up on the rivers Zeravshan and Magiyandare even in 1889: they have the longest series of observations of water flow. However, a systematic study of the major rivers of Tajikistan began only in the late 20-ies of XX century in connection with the development of large arrays of irrigated land (Vakhsh valley) after the organization of the Republican Hydrometeorological Service. The most rapid growth of the hydrological observation network took place in
60-80- years at the expense of the organization posts on small and medium-sized rivers with catchment area less than 100 km2. If the total number of gauging stations on rivers and lakes was respectively 94 and 4 by 1960, then by the middle of the 80s, their number reached 147 and 9.
Gauges is the first that is set on the river to reach the highest, the lowest levels, and other characteristics of water and its costs for many years, and every break in the observations is an irreparable gap in the study of rivers. Knowledge of typical levels necessary to produce gidrologiche6 cal forecasts, flood prevention, design and construction of hydraulic structures.
River Panj and Amu river
The water level is measured by the rails installed on each tide gauge. Measurement of water flow in the rivers rather narrow bridge made from gauging or cradle, suspended on ropes and on the river hundreds of meters wide, as the Panj, – on board the boat. To record the water level fluctuations in the river discontinuance are no longer special recorders. In the future it is planned to equip the hydrometric stations and hydro-meteorological stations of Tajikistan with modern devices. In accordance with the GEF program “Monitoring of transboundary waters,” the Office of the implementation of the Aral Sea basin projects in five Hydro-logical stations transboundary rivers set-hyd-parameter equipment firm SEBA Hydrometry Germany.
observations are made and their primary treatment at hydrological stations (photo 9). At the end of the month or after the measurement and processing of production materials are available on the hydrological station.
Hydrological station carried the organization and leadership of gauges monitor the implementation of the rules of recording and processing of observational data. Received from their posts at the plant materials are verified, coded and all information shall be included in the technical support, sent to the Tajik Met Service.
They made observations of quality assessment, completeness and timeliness of the materials sent and sent to the appropriate assessment of the results of the work station. Then the materials are included in the Hydrological Yearbook, which includes information on water resources: level, flow, water temperature, flow rate of suspended sediment, etc. In a number of elements (level and water temperature, turbidity, etc.) Following processing (calculation of average values for. day, month, year, selection of extreme values, statistical processing) is performed on a computer in the computer centers.
Photo Yakhsu the river in Vose district
In the early twentieth century, the problem of hydrometeorological support even a little worried about humanity: fresh water reserves seemed inexhaustible. Registration of water resources, monitoring the regime of rivers and reservoirs were most often episodically. Hydrological forecasts, as a scientific discipline, which is of great practical importance, developed in close connection with practical needs, and above all economic use of waters of the rivers and lakes.
Influence the development of forecast methods and questions that have arisen in the implementation of measures to prevent the harmful effects of floods and other hydrological phenomena.
Development of methods and preparation of hydrogeological forecasts were made possible when there is sufficient scientific knowledge about the most important events in the life of rivers and lakes, as well as the accumulated observations of these phenomena. In the context of high demand for water resources in Tajikistan the decision of the hydrological forecasting problems is important for the development of the republic’s economy, primarily agriculture and hydropower. Maintenance of economic and other organizations with information about the current and expected state of water bodies, as well as warnings about the expected hazardous hydrological phenomena, is the main task of the department of hydrological forecasts.
Activities Service hydrological forecasts based on the analysis of conditions of formation of hydrological phenomena in a given year and the previous years, on a thorough knowledge of the hydrological regime and scientifically – based methods of its forecast. For this purpose the observation data Fund hydrology, meteorology and related disciplines. Materials Fund, along with information about the current status of water bodies and the weather are the basis upon which all operational and research service of hydrological forecasts. From the completeness and quality of these materials depends largely on the success of the development of methods of hydrological forecasts, as well as the quality and efficiency of operational hydrological services of the national economy.
The main metrological stock materials are systematic observations over the level and water flow, water temperature, ice events, ice thickness and snow depth on the ice of rivers, lakes and reservoirs. In large lakes and reservoirs included observations on the excitement and the evaporation from the water surface, as well as the inflow and discharge of water from the reservoirs.
Collection of hydrological and meteorological information about the current status of water bodies and meteorological conditions in their basins is the most important work of the service of hydrological forecasts. Network hydrometeorologists-cal stations and posts, from which come all the relevant information, called information.
Information stations report the following information:
the thickness of the ice,
the presence of sludge,
snow depth on the ice,
wind waves, wind speed and direction on lakes and reservoirs,
Snow cover (height and density),
air temperature and precipitation.
For information about the levels and water temperature, as well as the ice phenomena stations transmit usually once a day; observations on the thickness of the ice and snow of the shooting – one every 10 days. During the passage of high floods and flood information about water levels are often transferred more often, two – three times a day.
Gunt River (in Pamire- Khorog)
Stations and stations transmit observations after production measurement by telegraph, telephone or
station. In addition to the regular supply of information, each station is obliged to inform the agency service of hydrological forecasts, data on such changes in the status of water bodies which pose a threat to human settlements, businesses and hydrological structures. In this case, the station sends an emergency telegram marked “storm”, going along the lines of communication out of turn. Data are transmitted in digital form small groups, suitable for telegraph and radio programs. Encoding and decoding of telegrams takes very little time, as codes are simple enough.
The problem of short-term and long-term forecasts is to estimate the future flow based on hydro-meteorological information received by the time of issuance. Currently, hydrological forecasts Tajik Met Service Department released the following forecasts:
The forecast for the decade – on two rivers: Vakhsh, Varzob. Forecast monthly for six rivers: Vakhsh, Varzob, Gunt, Isfara, Yakhsu, Kafirnigan.
Forecast for the growing season as well on the six rivers and river Vanj are consulted. The average accuracy of hydrological forecasts is 70-80%. The main reason for individual cases of inaccuracy is the lack of timely and full operational information from monitoring stations.
Practical value gidroprognozov determined by their accuracy and lead time. Forecasts small lead time (for a day, a decade) have a higher accuracy but lower efficiency, the forecasts also more lead time (month, season), although less precise, but more suitable for use in its consumer business. In the past ten days the first period of long-term forecasts are specified according to the prevailing hydrological conditions. Trade bodies to give long-term prognosis and refinement, can adjust their plans and tasks on the basis of more accurate calculations.
First of all the water of our rivers is irrigated agriculture. Many small rivers, especially in the Ferghana Valley, do not convey the water to his mouth, completely taken for irrigation. There are two hundred channels with a total length of 28 thousand kilometers in the country. Out on the Vakhsh water main canals for irrigation Vakhsh valley of Varzob on the Grand Canal Gissar moisture enters the field Hissar valley: the river Varzob brings to the mouth of only one-fifth of its flow.
On the rivers of Tajikistan Nurek were built, Kairakkum, Farkhad, Kattasayskoe, Muminabad, Selburinskoe and other reservoirs totaling more than fifteen billion cubic meters. Of these, the most capacious in terms of Nurek – 1D cube. km, and the largest in area Kairakkum – 520 square meters. km.
Give clean and cheap electricity power station on the Vakhsh, in the Vakhsh main canal on Varzob, on the Syr Darya, to Gunten on Vanj and many other rivers of Tajikistan. And this is only the beginning, ahead of the construction of new, more powerful hydroelectric power plants as the main source of electricity in our country – its rivers.
The role of rivers in Tajikistan as a transport communications significantly, but on the Amudarya and Panj barges and boats can go up to the pier Nizhny Panj and above.
Although household needs is spent only a few percent of all water consumed, it is this water – the most important, for the health and life of the entire population of the country on its purity.
Therefore, in our country, where the water depends on the crop, and hydropower, and industry, and health care, where water associated with such hazards as floods, flash floods, mudslides, or, on the contrary, the drought, the role of timely and accurate hydrological forecasts can not be overestimated.