Geography and Population
Uzbekistan (41°00' North, 64°00' East) is a landlocked country in Central Asia, with a total area of 447,400 square kilometers (km2). It is bordered in the north by Kazakhstan, in the east by the Kyrgyz Republic and Tajikistan, and in the south by Afghanistan and Turkmenistan. It became independent from the Soviet Union in August 1991. For administrative purposes, the country is divided into 12 vilayats (one of which includes the capital city of Tashkent) plus one autonomous republic: Karakalpakstan in the far west of the country near the Aral Sea.
Physiographically the country can be divided into three zones:
- the desert (Kyzylkum), steppe and semi-arid region covering 60% of the country, mainly the central and western parts;
- the fertile valleys (including the Fergana valley) that skirt the Amu Darya and Syr Darya rivers;
- the mountainous areas in the east with peaks of about 4,500 meters (m) above sea level (Tien Shan and Gissaro-Alay mountain ranges).
The cultivated land is estimated at 5.2 million hectares (ha), 87% under annual crops and 13% under permanent crops. Mainly because of water shortage, the cultivated area is only 20% of the cultivable area, estimated at 25.4 million ha. In 1994, the agricultural area could be divided into:
- kolkhoz (collective farms) and sovkhoz (state farms), for a combined area of 22 million ha;
- land leased to farmers for agricultural production on a long-term period (arenda), 76 800 ha;
- 'land of citizens', corresponding to gardens and individual plots cultivated by their owners, 477,500 ha;
- land managed by forest enterprises, about 1.97 million ha (Figure 1).
The total population is estimated at 23.2 million (1996), of which about 58% is rural. The average population density is about 52 inhabitants/km2, which is the highest of the five Central Asian republics. It ranges from more than 464 inhabitants/km2 in Andijan province (in the Fergana valley, in the east of the country) to only 8 inhabitants/km2 in Karakalpakstan. The annual population growth rate was stable at about 2.8-3.2% in the 1970s and 1980s, but fell to an average of 2.2% between 1990 and 1994. This fall has mainly been due to the prevailing difficult post-independence economic situation and the migration of a part of the population to other countries (the Russian Federation, Germany, Israel, etc.).
In 1994, the agricultural sector contributed some 36% to gross domestic product (GDP). In 1996, it employed about 33% of the total economically active population. The contribution of crop production to GDP was about 20% from irrigated crops and 2% from rainfed crops. Cotton, called 'white gold' in Uzbekistan, vegetables and fruits are the country's principal exports. Uzbekistan is one of the world's largest cotton exporters.
Climate and Water Resources
The climate of Uzbekistan is continental, even arid/desertic over 60% of the territory. The average annual rainfall is 264 millimeters (mm), ranging from less that 97 mm in the northwest to 425 mm in the mountainous zone in the middle and southern parts of country. In the Fergana valley, the average annual rainfall varies between 98 and 502 mm, while in the Tashkent vilayat, it varies between 295 and 878 mm. Rainfall occurs during the winter season, mainly between October and April. The climate is characterized by high temperatures in summer (42-47 degrees Celsius (ºC) in the plains and 25-30ºC in the mountainous zone in July) and low temperatures in winter (-11ºC in the north and 2-3ºC in the south in January). Because of frequent frosts between late September and April, only one crop a year can be grown. However, double cropping of vegetables which have a short growing period is possible in favorable years.
River Basins and Surface Water Resources
Two river basins are found in Uzbekistan. These basins form the Aral Sea basin:
- The Amu Darya basin in the south, covering 86.5% of Uzbekistan. The main Amu Darya River can be divided into three reaches: the upper reach bordering Afghanistan and Tajikistan, and where most of the water flow is generated; the middle reach which first borders Uzbekistan and Afghanistan and then enters Turkmenistan; and the lower reach in Uzbekistan, before it discharges into the Aral Sea. The main tributaries within Uzbekistan are the Sherabad, Kashkadarya, Surkhandarya and Zeravshan rivers. These last two rise in Tajikistan. The total amount of flow produced in the Amu Darya basin is estimated at 78.46 cubic kilometers per year (km3/year); the 5% and 95% probabilities are estimated at 108.4 and 46.9 km3/year respectively. Because of important losses in the desertic part of its course, and because of major water withdrawal by agriculture, the flow reaching the Aral Sea is limited to a small percentage of this figure (less than 10% in the driest years). About 4.7 km3/year, or 6% of the average total surface water resources of the Amu Darya River basin, are generated within Uzbekistan.
- The Syr Darya basin in the north, covering 13.5% of the territory. The main Syr Darya River can be divided into three reaches: the upper reach in the Kyrgyz Republic, where most of the water flow is generated; the middle reach in Uzbekistan and Tajikistan; and the lower reach in Kazakhstan, before it discharges into the Aral Sea. The main tributaries within Uzbekistan are the Chirchik and Akhangaran rivers, which rise in the Kyrgyz Republic. The total amount of flow produced in the Syr Darya basin is estimated at 37.14 km3/year; the 5% and 95% probabilities are estimated at 54.1 and 21.4 km3/year respectively. Because of important losses in the desertic part of its course, and because of major water withdrawal by agriculture, the flow reaching the Aral Sea is limited to a small percentage of this figure (less than 5% in the driest years). About 4.84 km3/ year, or 13% of the average surface water resources of the Syr Darya river basin, are generated within Uzbekistan.
The total river flow generated inside Uzbekistan is thus estimated at 9.54 km3/year (Figure 2).
During the Soviet period, the sharing of water resources among the five Central Asian republics was on the basis of the master plans for water resources development in the Amu Darya (1987) and Syr Darya (1984) basins. In 1992, with the establishment of the Interstate Commission for Water Coordination, the newly independent republics decided, with the Agreement of February 18, 1992, to prepare a regional water strategy, but to continue to respect the existing principles until the adoption of a new water sharing agreement to be proposed by this new water strategy.
The surface water resources allocated to Uzbekistan are calculated every year, depending on the climatic situation and the existing flows. However, on average, it can be considered that the estimated average surface runoff that comes from the upstream countries is:
- 22.33 km3/year for the Syr Darya River basin at the border between the Kyrgyz Republic and Uzbekistan, of which 11.8 km3/year is transit flow to Tajikistan
- 11.54 km3/year for the Syr Darya River basin at the border between Tajikistan and Uzbekistan, of which 10 km3/year is transit flow to Kazakhstan
- 22 km3/year for the Amu Darya River basin.
There are 94 major aquifers in Uzbekistan. The renewable groundwater resources are estimated at 19.68 km3/year, of which 12.88 km3/year are considered to be overlap with surface resources. The actual renewable water resources (ARWR) can thus be estimated at 50.41 km3/year.
Limits to groundwater abstraction for each aquifer in Central Asia have been established. It is permitted to use only such a quantity of groundwater that does not cause surface flow reduction. This quantity is estimated at 6.8 km3/year for Uzbekistan. However, the actual groundwater abstraction is estimated at 7.5 km3/year, which thus leads to surface flow reduction.
Non-conventional Sources of Water
Between 1990 and 1994, the return flow on the territory of Uzbekistan was estimated at about 32.4 km3/year, of which 21.5 km3/year formed in the Amu Darya River basin and 10.9 km3/year in the Syr Darya River basin. This total consists of 30.9 km3/year of drainage flow from irrigated areas (of which 2.55 km3/year is the result of vertical drainage by pumping) and about 1.5 km3/year of untreated domestic and industrial wastewater.
The main part of the return flow, 15.9 km3/year, returns to rivers: 9.5 km3/year in the Amu Darya basin and 6.4 km3/year in the Syr Darya basin. About 12.0 km3/year end up in natural depressions (Arnasay, Parsankul, Sarakamish and Lake Sudochie) from which water evaporates. More than 4.5 km3/year (about 15% of total return waters) are reused for irrigation:
- 2.9 km3/year being reused without any treatment, mainly for cotton on light soils.
- 1.6 km3/year being reused after an in situ desalting treatment (`phytomelioration').
Lakes and Dams
The collector-drainage water outflow has led to the creation of artificial lakes in natural depressions. The largest lakes are: Lake Aydarkul, in the Arnasay depression in the middle reach of Syr Darya, storing about 30 km3 in 1995; the Sarykamish and Sudochie lakes, both located in the lower reach of the Amu Darya, storing 8 and 2 km3 respectively. Several lakes have also been formed in the central part of the country in the Amu Darya basin, the largest being Lake Parsankul storing about 2 km3, close to the Zeravshan River.
There are 50 reservoirs in Uzbekistan with a total capacity of about 19 km3; 21 of them with a total capacity of 5 km3 in the Syr Darya basin, and 29 with a total capacity of 14 km3 in the Amu Darya basin. The largest reservoirs are multipurpose dams, used for irrigation, flood control, and hydropower production.
In the Syr Darya basin, the largest reservoirs are the Charvak reservoir, with a capacity of 1.99 km3, on the Chirchik River near the capital Tashkent, and the Andijan reservoir, with a capacity of 1.9 km3, on the Karadarya River in the Fergana valley.
In the Amu Darya basin, the largest reservoir is the Tuaymuyun, in the Khorezm vilayat, with a storage capacity of 7.8 km3, consisting of four separate reservoirs. It is expected that in the future one reservoir of this system (Kaparas) will be used to provide drinking water for Karakalpakstan. This area is experiencing severe environmental problems as a result of the shrinking of the Aral Sea. At present, the drinking water supply for this zone comes from groundwater which is too saline.
The gross theoretical hydropower potential is estimated at 88,000 gigawatt hours per year (Gwh/year) and the economically feasible potential would be 15,000 GWh/year. The total installed capacity, 1.7 gigawatts (GW) in 1993, provided about 12% of the country's electricity in 1995.
Water, Withdrawal, and Wastewater
In 1994, the total annual water withdrawal for agricultural, domestic, and industrial purposes was estimated at 58.05 km3 (Figure 3). This amount included withdrawal from surface water (46.16 km3), from groundwater (7.39 km3), and withdrawal from return flow collector-drainage for irrigation purposes, estimated at 4.5 km3 (Figure 4). Requirements for fisheries were estimated at 530 million cubic millimeters (mm3).
The total water withdrawal increased steadily from 45.5 km3 in 1975 to 62.8 km3 in 1985, mainly because of irrigation expansion. Since 1990, when the water withdrawal was 62.5 km3, the trend has been downward, due to agricultural water saving methods and a recession in the industrial sector.
Irrigation and Drainage Development
The history of irrigation started more than 2,500 years ago in the seven natural oases in Uzbekistan: (1) the Tashkent valley in the northeast of the country; (2) the Fergana valley in the east; (3) the Zeravshan valley in the east-central part; (4) the Kashkadarya valley in the southeast; (5) Surkhandarya in the southeast; (6) Khorezm in the west-central part; (7) Karakalpakstan in the northwest.
At the beginning of the twentieth century, about 1.2 million hectares (ha) were irrigated in Uzbekistan. Large-scale development started in the late 1950s, when the Soviet Union decided to specialize Uzbekistan in the production of cotton. Modern irrigation techniques were then developed in the Hunger steppe in the central part of the country, in the Syr Darya basin, and in the Karshi steppe in the southeast of the country in the Amu Darya basin. In 1994, irrigation covered almost 4.3 million ha, or about 82% of the cultivated land (Figure 5).
Irrigated land produces more than 90% of crop production. About 44% of the total irrigated area is in the Syr Darya basin and 56% in the Amu Darya basin. Considering that about 634,400 ha are suitable for irrigation and that water saving would enable a further limited expansion of the irrigated area, the irrigation potential can be estimated at 4.9 million ha.
All irrigation is full control irrigation, mainly using surface water (Figure 6). Wastewater and drainage water are mixed with surface water before being reused for irrigation. Thus, it is not possible to count them separately.
Irrigation in Uzbekistan relies on a system of pumps and canals which is among the most complex in the world. Water is lifted by electric pumps for the irrigation of 1.17 million ha. In 1994, there were about 1,500 pumps. To give some examples: the Karshi system lifts 350 cubic meters per second (m3/s) of water from the Amu Darya over an elevation of 170 meters; the Amubukhara pump system discharges 270 m3/s from the Amu Darya to a canal situated 57 m above the river; the Amu Zang pump system discharges 20 m3/s from the Surkhandarya to a canal 75 m above the river. The total length of the irrigation network is about 196,000 km. The main canals and inter-farm network extend for a length of about 28,000 km, of which some 33% is lined. The on-farm network is about 168,000 km, most of it consisting of unlined earthen canals (Figure 7).
In 1994, surface irrigation was practiced on 99.9% of the total area, mainly furrow. Drip irrigation covered 4,510 ha in 1994, or only 0.1% of the total area. Sprinkler irrigation was no longer practiced in 1994, although it had covered some 5,000 ha in 1990. Greatly increased energy costs and a lack of spare parts mean that this technique is not economically viable (Figure 8).
The average weighted efficiency of the irrigation network, which shows the water losses along the distance between the source and the irrigated field, is 63% (1994). The average annual water withdrawal for irrigation was estimated at 12,477 cubic meters per hectare (m3/ha) in 1994, and it is estimated that irrigation water requirements were covered at 80-90%. Major differences can be observed between old and new irrigated areas. New irrigated areas have been developed since 1960 with lined canals, pipes, and flumes in the on-farm network, and a subsurface drainage system, which together enable an efficiency of 75-78%. Rehabilitation and modernization of the old irrigated areas would concern 2.3 million ha with an average cost of about $US4,500/ha. The two main elements of such works would be laser land levelling and the introduction of modern irrigation techniques (e.g., drip, surge).
The average cost of irrigation development is about $US11,200/ha, for surface irrigation schemes using standard modern technologies, including agricultural infrastructure. Drip or surge irrigation equipment adds $US2,300/ha to this total. The cost of drip irrigation development on existing irrigated areas varies between $US2,300 and 3,500/ha.
There are no private irrigation schemes in Uzbekistan. Each large scheme (Hunger steppe, Karshi steppe, etc.) is managed by a state agency. Small schemes are managed by district water management agencies, which often manage several schemes at once. Operation and maintenance (O&M) charges are covered by the government for kolkhoz and sovkhoz, and by farmers when land is leased to them, although they are heavily subsidized by the government. The average annual O&M cost which enables full recovery is about $US450/ha for standard systems, and more than $US640/ha for drip irrigation or $US680/ha for pump systems, while in recent years the actual cost has varied between $US60 and 150/ha.
Farms are not charged for irrigation water, but in 1995 a land tax was introduced. The amount payable depends on irrigation and land quality, which is calculated by province on the basis of a soil fertility parameter. For example, in Karakalpakstan, the tax varies from $US0.64/ha for the lowest fertility class to $US6.5/ha for the best fertility class. In the south of the country, the tax varies between $US1.1 and 11.2/ha.
Cotton is by far the major irrigated crop, followed by fodder, wheat, and fruits (Figure 9). During the past few decades, irrigated yields have been fairly stable. In 1993, yields were 2.51 t/ha for cotton, 2.06 t/ha for wheat, 2.96 t/ha for rice, and 4.02 t/ha for grapes.
Waterlogging, Salinity, and Drainage Development
The two major land quality problems in the country are the interrelated issues of salinity and waterlogging caused by high groundwater levels. In 1994, only 50% of the irrigated land was classed as non-saline by Central Asian standards (toxic ions represent less than 0.5% of total soil weight). In the upper reaches of the Amu Darya and Syr Darya basins, less than 10% of the land is saline or highly saline, while downstream (especially in Karakalpakstan) about 95% of the land is saline, highly saline, or very highly saline. Salinity is closely related to drainage conditions. Moreover, since 1990, a reduction in the quantity of water allocated to each farm, lower water quality, and the decay of companies responsible for maintaining the drainage network have resulted in increased salinization. Though loss of crop production due to soil salinization is important, salinized land is generally still cultivated.
About 3.3 million ha of irrigated land would require man-made drainage. Only 2.8 million ha are currently equipped with drainage infrastructure. Most of the drainage systems are open drains (Figure 10). Vertical pumping drainage is carried out on 401,000 ha, mainly on clay soils. In the newly reclaimed areas (Hunger and Djizak steppes in the Syr Darya basin, Surkhan-Sherabad and Karshi steppes in the Amu Darya basin), drainage is mainly subsurface drainage. The total length of main and inter-farm collectors is about 30,000 km, while the on-farm collector-drainage network extends for about 110,000 km.
The Water Resources Department of the Ministry of Agriculture and Water Resources Management, established in 1996 after the merger of the Ministry of Agriculture and the Ministry of Water Resources, is in charge of water resources research, planning, development, and distribution. It also undertakes the construction, operation, and maintenance of the irrigation and drainage networks at the inter-farm level in the country. Water allocations are regularly reduced in order to promote savings and to satisfy the demand from new users and to increase the water flow to the Aral Sea. Water withdrawal per year thus declined from 17,500 m3 in 1980 to 11,600 m3 in 1995, while irrigation efficiency increased. The total annual irrigation water withdrawal declined from 58.8 km3 in 1990 to 53.4 km3 in 1994.
Institutional organizations dealing with water management at state, provincial, and district level come under the Water Resources Department. Such organizations are responsible for water distribution and delivery to the farm inlet, for assisting water users in implementing advanced technologies, and for water use and water quality control. The special land reclamation service, under the Water Resources Department, monitors the main reclamation indicators of irrigated lands (groundwater level, drainage discharge, soil salinity, situation of the collector-drainage network) at national, provincial, and local level. It also plans the required measures for irrigation and drainage network maintenance and for the reclamation of degraded lands, including leaching, repairing, and cleaning of drainage-collectors and network rehabilitation.
A water law was approved in May 1993. It introduced the notion of water rights. Within the general objective of water savings, Article 30 emphasizes the need for water pricing, although it still leaves room for subsidies to the water sector.
The Ministry of Agriculture and Water Resources Management is also in charge of agricultural research and extension, on-farm agricultural and land reclamation development, and on-farm operation and maintenance of the irrigation network.
The Ministry of Municipal Affairs is responsible for domestic water supply and wastewater treatment.
Research in the water resources development sector is undertaken by the Central Asia Scientific Research Institute of Irrigation (SANIIRI). This autonomous institute of the Ministry of Agriculture and Water Resources Management was previously responsible for all Central Asia. It also manufactures irrigation equipment.
The Goskompriroda (Environment State Committee) is in charge of water quality monitoring and control of industrial and municipal pollutants.
Uzbekistan is a member of IFAS, ICWC, the Amu Darya, and Syr Darya River BWOs.
Trends in Water Resources Management
Irrigation has created serious environmental problems in Uzbekistan, the most dramatic effect being the shrinking of the Aral Sea. According to a World Bank report, the main environmental impacts of irrigation in the Aral Sea basin include: (1) the loss of fish resources in the Aral Sea, due to an increase in salinity and chemical pollution; (2) land degradation through waterlogging and salinization of irrigated land; (3) crop diseases and pests, due especially to the cotton monoculture; (4) adverse health effects on people and animals, due to wind-blown chemicals and the poor quality of water; and (5) possible local climatic change.
Drainage water is the principal carrier of environmental pollution, since it contains the results of mineralization and residues from pesticides.
The restoration of the Aral Sea to its 1960 level is not an objective for the country, although assistance to the 'disaster' zone is seen as a priority. Actions to be taken are: the stabilization of the exposed seabed; land reclamation in the delta; improved drinking water supply, health, and general actions to promote the socio-economic conditions of the population in the area.
In a context of demographic growth and higher demand for water from the industrial and domestic sectors, it is now generally accepted that the Aral Sea should be maintained at its present level. This also implies that water management has to be improved, in order to constantly reduce water withdrawal for irrigation. This could be achieved through reducing water losses from the inter- and on-farm irrigation network, and through increasing overall production in a sustainable way, notably by implementing techniques for the desalinization of irrigated land. The construction of a major collector to bring drainage water from the lower Amu Darya irrigated areas directly to the Aral Sea has been undertaken. This measure also favors the stabilization of the Aral Sea level and the improvement of water quality in the main rivers.
Water savings in irrigation should enable the development of other sectors of the economy. An important thrust of irrigation and water management improvement at the on-farm level would be to move from a state-run system to privatization of irrigated agriculture, notably through the establishment of Water User Associations (WUAs). This process is developing at a very slow pace. Implementation of water pricing in the industrial and municipal sectors, as well as agricultural water pricing, may also provide room for water savings in the future.
At the international level, mechanisms to introduce water quality issues into water sharing agreements are under discussion.
- Uzbekistan Water Projects, Uzbekwater.net.
- Water Resources and Freshwater Ecosystems: Uzbekistan, Earthtrends.
- Country Water Actions: Uzbekistan, Asian Development Bank.
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