Translated from the original by Vatansho Vatanshoev
Link: (PDF, Russian), Ministry of Nature Protection, Tajikistan, 2003
Powerful mountain ranges of Tajikistan and their branches create several hydrographic areas, forming two main river systems - the Amu Darya and Syr Darya.
The northern Tajikistan is the primary basin of the Syr Darya. The total average area of Syr Darya is about 13,400 Km2; -- almost one tenth of the area of the republic. Most of the area of the country is located in the basin of this river. Amu Darya is formed out of the divided mountain ridges, which have watersheds of various height and degrees of glaciations, different development of the river networks, flow formation conditions, and runoff system. The North-eastern Pamir is the only territory that doesn't contribute to these two great rivers (basins of Karakul Lake of Markansu River).
Hydrographic network of Tajikistan is constituted of more than 25 thousand rivers with a total length of 69,200 km. Out of these, 947 rivers have a length from 10 to 100 km, 16 rivers - from 100 to 500 km, and 4 rivers longer than 500 km ( map 1 ). According to the geographical status of Tajikistan's river network, the country is divided into the following major river basins -- Zaravshon, Surhandarya (Karatag & Sherkent rivers), Kofarnihon, Vakhsh, and Panji, (Gunt, Bartang, Yazgulem, Vanj, Southern Kizilsu ).
The largest rivers: river Pyanj - 521 km, river Vakhsh - 524 km, river Bartang - 528 km, river Kofarnihan - 387 km, Zaravshan - 310 km (full length of 877 km), and Syrdarya (within Tajikistan) 180 km ( map 2 ).
The average annual river flow is 56.2 km3. The main source of moisture is seasonal snow. On southern slopes of Hissor, and Karotegin-Alay ridges falls up to 2000 mm of precipitation a year, mainly as snow, which melts before the end of June. In the highlands, where short and cool summers are common, the snow does not to melt but accumulates, gradually turning into ice. Thus, glaciers are formed, whose role in feeding the rivers of Tajikistan is very great because they give each about 13 km3 of water during the summer peak temperatures. Most of the rivers in Tajikistan originate from glaciers. Tajikistan's rivers can be divided into four main types ( photo 1.)
Glacial-snow rivers. The flow lasts until seven months of the year with the largest volume of water in July and August. This is relevant to almost all major rivers in the country -- Vanj, Pyanj, Zaravshon, etc. ( photo 2-3 ).
Snow-glacial rivers. The example of these rivers are Karatag and Kofarnihan with their tributaries, including the Varzob river, which reaches the capital of the republic. Their highest volume is around May-June.
Snow rivers. Flow lasts four to six months, with the greatest volume in in April or May. These are rivers like Kofarnihan, tributary of Varzob - Luchob, Harangon and others ( photo 4).
Snow-rainwater rivers. These type of rivers usually for at lower elevation. Flow lasts about four months, with its peak in April. These are rivers like Kizilsu (Southern), Yakhsu, Tairsu, etc.
Thus, one of the main differences between mountain rivers and those in lower elevation (lowlands) is a long and stormy flow, during which the river runs 70 - 90% of its annual flow.
Tajikistan has a very abundant water resources. The average water flow from one square kilometer is 354 thousand cubic meters per year - four times more than the average for the entire region of Central Asia. In flood season the rivers have large amounts of suspended sediment, which increase land erosion by water. For example, Kofarnihan moves about 10 million tons of sediment each year and the South-Kizilsu -- more 15 million tons. As a result, in one place the banks are blurred, in others - ground and islands appear. Therefore, a lot of money is spent annually to secure the banks and dams of such destructive rivers ( Photo 5 ).
The rivers of Tajikistan are not only a sources of moisture, without which the country would become a desert, but also represent the highest hydropower potential among all the CIS countries. Tajikistan ranks second after Russia. Only the major rivers and their tributaries can generate 300 billion kilowatt / hours electricity a year. On Vakhsh river, there are already five hydroelectric plants, among which is the largest in Central Asia - the Nurek hydroelectric power station, with a production of 3 million kilowatts. The same Vakhsh river has a potential for 5 cascade hydropower plants with a total capacity of 8 million kilowatts, and Panj river has even twice as much hydro-potential as Vakhsh ( Photo 6 ).
First water flow measuring stations have been established on the rivers Zaravshon and Magiyandaryo in 1889: they have the data for the longest time period of water flow. However systematic study of major rivers began in Tajikistan only at the end of 20's, in the twentieth century with the development of large irrigated lands (Vakhsh Valley) and after foundation of the "Gidrometsluzhba" - Hydro-Meteorological Service. The most rapid growth in the number of hydrological observation stations took place in 60-80's through the organization of stations on small and medium-sized rivers with the flows of less than 100 km2. In 1960 the total number of stations on rivers and lakes was 94 and 4 respectively, while by mid 80's their numbers reached 147 and 9. Water flow measuring stations are important instrument to measure the highest, lowest and other typical levels of water and its flow for many years. Each break in observations is irreversible data loss in the study of rivers. Knowing the levels of water in rivers can be helpful in flood prevention, meteorological predictions, design and construction hydraulic structures ( Photo 7 ).
The level of water is measured with the slats installed on at each station. Measuring the flow of water on relatively narrow rivers has been done with hydrometric bridge or lifts, suspended on cables, and in wider rivers -- more than 100 meters, as for example Pyanj river, it is done from on board of a boat. To record the fluctuations in water level in the river -- special self-recording devices are installed at the station.
In the future, it is planned to upgrade and equip the established hydro-meteorological stations in Tajikistan with modern technologies. In accordance with the "Monitoring of Trans-boundary Waters" program which is directed towards improvement of Aral Sea Basin hydrological conditions, hydro-meteorological equipment of the German company - "SEBA Gidrometria" was installed in five hydro-meteorological stations, on major rivers ( photo 8 ). The hydrological observation stations are the starting point in organizing and analyzing the obtained data ( photo 9 ). At the end of the month, immediately after the appropriate measurement and processing, the data is sent to the Hydrological Center. Hydrological Center is responsible for organizing the hydro-meteorological stations; monitoring the accuracy of their observed data and performed activities. The data is processed and than sent to the GlavTajikGidromet, I will be taken into record there for more comprehensive analysis ( photo 10 ).
GlavTajikGidromet assesses the quality of observations, their consistency, and sends performance evaluation to the hydro-meteorological stations. Then the data is included in the hydrological "yearbook", which includes an information on water resources: their level, flow, water temperature, flow rate of suspended sediment and several others characteristics ( turbidity, etc.). Also, subsequent processing of data (average computation values per day, month, year, sampling extreme values, statistical processing, etc.) is done on computer in the computer centers ( photo 11 ). In the early twentieth century hydro-meteorological problems provided a little concern to humanity: it seemed that freshwater was inexhaustible. Monitoring of water resources, treatment of rivers and reservoirs were the done occasionally. Hydrological forecasts as scientific analysis of the water resources has become part of development and economic use of waters, rivers, and lakes.
The analysis also helps to prevent the harmful effects of floods and other hydrological events. Development of hydrological projections had become possible when a sufficient scientific knowledge about the critical events in he life of rivers and lakes was generated; the accumulated observation on these phenomena is a key. With a large demand of water resources throughout the territory of Tajikistan, it is important to meet the challenges of hydrological forecasting and analysis in order to improve the economic development the republic, primarily agriculture and hydropower.
Serving the national economy and organizing information on current water facilities as well as warnings about expected dangerous hydrological phenomena is the main task of the Department of Hydrological Forecasts. Activities of the department are based on the analysis of the hydrological conditions and events in present and previous years, as well as deep knowledge of the hydrological regime and sound scientific methods of forecasting. For this purpose - the Fund for Hydrological Analysis (and related subjects) was created. The main hydrological data represents the systematic observations of the level and flow of water, water temperature, ice phenomena, ice and snow thickness at the surface of the ice rivers, lakes and reservoirs. Accordingly, the major lakes and reservoirs involve observations on the waves and evaporation as well. The collection of hydrological and meteorological information about current status of water bodies and meteorological situation in their pools is the most important work carried out by the hydrological forecasting service. Hydrometeorology network stations and posts, which receive all necessary data are called Information Stations. Information Station report the following information:
1) the water level, 2) the rate of water flow, 3) water temperature, 4) ice phenomenon, 5) ice thickness, 6) The presence of studge ice, 7) the height of snow cover on the ice, 8) Wind frequency, wind speed and direction at lakes and reservoirs, 9) snow cover (height and density), 10) the air temperature and precipitation.
Information about water levels and water temperature, as well as ice phenomenon are reported only once a day; observational data about the thickness of ice and the results of snow records - once every 10 days. Water flow and level is reported more often: two - three times a day ( photo 12 ). The stations and posts transmit the recorded data by telegraph, telephone or radio station. In addition to regular report of data, each station is also obliged to report to the Hydrological Forecasting Center any hydrological changes that pose a threat to human life, institutions and businesses, and hydrological facilities. In this case, station sends urgent telegram with a mark "Storm", that travels with a special priority (out of turns). The data is than digitized after it was transmitted by telegraph and/or radio. Encoding and decoding telegrams takes very short time, as well as codes are fairly simple. The task of short and long-term forecasts is to predict the future hydro-meteorological phenomenon by analyzing the current data. Currently, hydrological department GlavTajikGidromet released the following projections: forecast for a length of a decade on two main rivers: Vakhsh and Varzob. The forecast for a month on other six rivers - Vakhsh, Varzob, Gunt, Isfara, Yakhsu, and Kafirnigan is also released. Forecast of the growing season just for the six rivers turned out to be very useful. Average accuracy of the hydrological forecasts is 70-80%. The main reason for individual cases of inaccuracy is the lack of timely and full operational information from the observation stations. The practical value is determined by their hydro-forecasting accuracy and advance. Projections for the nearest future (for the night, 2 days, etc.) have a higher accuracy but less value, as more advanced forecasts (for a month, season), though less accurate, but are more appropriate for use in consumer economic activities. In the first period of 10 days clarifies the long-term projections under the current hydrological conditions. Household authorities, receiving long-term prognosis, can adjust their plans and objectives, based on more accurate calculations.
Primarily, the water from the rivers is used for irrigation purposes. Many small rivers, especially in the Ferghana Valley do not reach their destination point; they are depleted long before that.
Map 1. Hydrographic situation
Map 2. The main river basins
Photo 1. East River at Pamir
Photo 2. Zaravshan River
Photo 3. Gunt River
Photo 4. Varzob river
Photo 5. The collapse in the mountain into a river
Photo 6. Surkhob river
Photo 7. Hydrological station on Obihingou river
Photo 8. Installation of equipment across the Kofarnihon river
Photo 9. Measuring the flow of water at Vahsh river
Photo 10. A set of observational data on computer
Photo 11. Handling annual data on computer.
Photo 12. Obihingou River.
Tajikistan has two hundred channels with a total length of 28 thousand kilometers. The Vakhsh water channel is used to irrigate the Vakhsh valleys. The Varzob river gave birth to the Big Hissor channel which supplies water to the farm fields in Hissor Valley. The Varzob river maintains only the fifth of its runoff by the time it reaches its destination point. Hydropower plant water reservoirs like Nurek, Kairakum, Farhad, Kattasay, Muminabad, Selburin and other contain more than fifteen billion cubic meters of water. Of these, Nurek has the greatest volume - about 1 km3, and the Kayrakkum reservoir has the largest area - 520 km2. This is just the beginning, more ambitious projects are ahead and will have more powerful hydroelectric potential. The rivers are the key in this important energy production. The role of rivers in Tajikistan as a transport or for communications is irrelevant, however the Amu Darya and Pyanj have some potential for barges and boats that may travel up to Nizhny Pyanj and above.
Click for the original (Russian) at the following link: (PDF, Russian), Ministry of Nature Protection, Tajikistan, 2003