Tajikistan : Climate and Water Resources

Climate

The climate of Tajikistan is classed as continental, but its mountainous terrain gives rise to wide variations. In those areas where cultivation takes place, which is mainly in the floodplains of the rivers, the climate consists of hot, dry summers and mild, warm winters. The average annual precipitation is 691 millimeters (mm), ranging from less that 100 mm in the southeast up to 2,400 mm on the Fedchenko Glacier in the central part of the country. Precipitation occurs during the winter season, mainly between September and April. The average temperature is about 16°-17°C. The absolute maximum temperature recorded is 48°C in July, the absolute minimum temperature -49°C in January. The daily temperature range is about 7°C in winter and 18°C in summer.

River Basins and Water Resources

Tajikistan can be divided into four major river basins:

• The Syr Darya basin. The northwest of the country forms part of the Syr Darya basin. About 78% of the flow of the Syr Darya River is generated on the territory of the Kyrgyz Republic. Only 1% of the total flow of the Syr Darya River is generated within Tajikistan by the shallow rivers Khodzhabakirgan, Aksu, Isfara, and Isfana, with a total flow of 0.4 km3/year.
• The Amu Darya basin. About 82.5% of the flow of the Amu Darya River is generated on the territory of Tajikistan by the Vakhsh, Pyandzh and Kafirnigan rivers. The Vakhsh River is the largest river in Tajikistan, crossing it from the northeast to the southwest. It rises in the Kyrgyz Republic, where it is called the Kyzyl Suu, and its catchment area lies in the highest part of Tajikistan at over 3,500 meters. The Pyandzh River forms the border between Tajikistan and Afghanistan for almost its entire length. After the confluence with the Vakhsh River, it becomes the Amu Darya River and about 100 km further downstream it leaves Tajikistan to become the border between Afghanistan and Uzbekistan. The Kafirnigan River is another large tributary of the Amu Darya River. It rises in Tajikistan and flows into the Amu Darya River about 36 km downstream of the confluence of the Pyandzh and Vakhsh rivers.
• The Zeravshan basin. The Zeravshan River, rising in Tajikistan, was once the largest tributary of the Amu Darya River. At present its flow is almost fully used, mainly for irrigation.
• The basin draining to China. In the extreme northeast of the country, a small area drains towards China. No figures on flows are available.

Non-conventional sources of water

The total internal renewable surface water resources (IRSWR) of Tajikistan are estimated at 63.3 km3/year (Figure 2). During the Soviet period, the sharing of water resources among the five Central Asia republics was on the basis of master plans for the water resources development in the Amu Darya and Syr Darya river basins. With the establishment of the Interstate Commission for Water Coordination in 1992, the newly independent states decided to prepare a regional water strategy (Agreement of 18 February 1992), 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 Tajikistan are thus calculated every year, depending on the existing flows. However, on average, it can be considered that the surface water resources available for Tajikistan are 12.98 km3/year.

The internally generated renewable groundwater resources are estimated at 6 km3/year, of which 3 km3/year overlap with surface water resources. The part of groundwater resources for which abstraction equipment exists has been estimated at 2.2 km3/year.

The actual renewable water resources (ARWR) of Tajikistan can thus be estimated at 15.98 km3/year.

Non-conventional sources of water

In 1994, the return flow within Tajikistan amounted to 4.36 km3/year, including 3.78 km3/year of collector-drainage flow from irrigation and about 0.58 km3/year of domestic and industrial wastewater. The main part of the return flow, about 3.94 km3/year, flows back to rivers, of which 2.85 km3 into the Amu Darya River and 1.09 km3 into the Syr Darya River. More than 0.35 km3/year (8% of total return water) are re-used for irrigation. The remaining 0.06 km3/year of return flow are directed to natural depressions.

There are 1,300 natural lakes in Tajikistan with a total water surface area of 705 km2 and a total capacity of about 50 km3. About 78% of the lakes are situated in the mountain zone above 3,500 meters (m) above sea level. The largest lake in the country is Lake Karakul in the northeast at an altitude of 3,914 m, with a surface area of 380 km2 and a capacity of 26.5 km3.

In 1994, the return flow within Tajikistan amounted to 4.36 km3/year, including 3.78 km3/year of collector-drainage flow from irrigation and about 0.58 km3/year of domestic and industrial wastewater. The main part of the return flow, about 3.94 km3/year, flows back to rivers, of which 2.85 km3 into the Amu Darya River and 1.09 km3 into the Syr Darya River. More than 0.35 km3/year (8% of total return water) are re-used for irrigation. The remaining 0.06 km3/year of return flow are directed to natural depressions.

Lakes and dams

There are 1,300 natural lakes in Tajikistan with a total water surface area of 705 km2 and a total capacity of about 50 km3. About 78% of the lakes are situated in the mountain zone above 3,500 meters (m) above sea level. The largest lake in the country is Lake Karakul in the northeast at an altitude of 3,914 m, with a surface area of 380 km2 and a capacity of 26.5 km3.

In 1994, there were 19 dams in Tajikistan: 5 in the Syr Darya River basin and 14 in the Amu Darya River basin (7 on the Vakhsh River, 4 on the Pyandzh River and 3 on the Kafirnigan River). Their total reservoir capacity is about 29 km3 and the reservoir area 934 km2. There are nine large reservoirs (capacity more than 500 million m3 each) with a total capacity of 25.34 km3 and an area of 690 km2. The largest reservoirs are: the Nurek on the Vakhsh River (10.5 km3), the Kayrakkum on the Syr Darya River (4.16 km3), and the Lower Kafirnigan on the Kafirnigan River (0.9 km3). The Nurek headwork incorporates a unique rock-fill dam with a central core, 310 m in height, a power plant with a capacity of 2,700 megawatts (MW) and a reservoir with a capacity of 10.5 km3. The Rogun reservoir on the Vakhsh River (8.6 km3) has been planned, but not yet constructed. The main purposes of the reservoirs are hydropower production and irrigation.

The gross theoretically hydropower potential of Tajikistan is estimated at 527,000 gigawatt hours (Gwh)/ year, about half of which would be economically feasible. In 1994, the total installed capacity was about 4 GWh, generating about 98% of the country's electricity. Tajikistan ranks third in the world for hydropower development, after the United States and the Russian Federation.

Water withdrawal and wastewater

In 1994, the total annual water withdrawal was estimated at 11.87 km3, of which over 92% was for irrigation purposes (Figure 3). About 2.26 km3 was groundwater, an estimated 0.35 km3 re-used collector-drainage water and wastewater for irrigation, and the remainder was surface water (Figure 4). In 1995, the total water demand for all sectors was estimated at 12.955 km3.

Irrigation and drainage development

Irrigation development

Irrigation in Tajikistan is important for the development of agriculture and the national economy. In 1960, the total area equipped for irrigation was estimated at about 408,000 hectares (ha). In 1994 it was 719,200 ha, which was 93.4% of the total cultivated area (Figure 5). About 33% of the total irrigated area (240,200 ha) is situated in the Syr Darya River basin and 67% (479,000 ha) in the Amu Darya River basin, of which 20,000 ha in the Zeravshan basin, 49,000 ha in the Kafirnigan basin, 18,000 ha in the Pyandzh basin and 392,000 ha in the Vakhsh basin. Considering that a further 36,000 ha are potentially suitable for irrigation development up to 2010, the total potential for irrigation development has been estimated at 755,200 ha.

In northern Tajikistan, irrigation is mainly based on the water resources of the Syr Darya River, whose water is delivered by pumping stations. The Tajik part of the Hunger steppe is bordered in the northwest by Uzbekistan. This region belongs to a semi-desert zone and the irrigated area is about 39,000 ha, mainly used for cotton. Water is taken from the diversion canal of the Farkhad power plant in two stages by remote-controlled pumping stations, which lift the water to an elevation of 170 m. In 1994, the total power irrigated area was estimated at 318,000 ha.

Large-scale irrigation development in southern Tajikistan started in 1931 with the construction of the Vakhsh main canal in the Vakhsh valley. This canal is 11.7 km long with a capacity of 150 m3/s, diverting water from the Vakhsh River for the irrigation of 120,000 ha. The Vakhsh main canal was later reconstructed, its capacity increased to 200 m3/s and the canal extended to irrigate also the Akgazin plateau.

During the Soviet period, important irrigation development took place in the Kafirnigan River basin, located in southern Tajikistan. Together with Uzbekistan, Tajikistan built the Large Gissar canal in 1940, which carries water from the Dushanbe River into the basin of the Surkhandarya River (situated in Uzbekistan). The irrigated area in this part of Tajikistan is about 29,000 ha.

Further irrigation development in southern Tajikistan took place with the construction of the Nurek and Baipaza dams on the Vakhsh River. Water is provided for the irrigation of 76,000 ha in the Dangarin area. In the Vakhsh basin, a large irrigation system (40,000 ha) is located in the Yavan and Obikiik valleys, which are extremely short of water. At present, the valleys are supplied with water from the Baipaza reservoir through a tunnel 7.3 km long.

Surface irrigation is the only irrigation technique used in Tajikistan. In 1994, furrow irrigation was practiced on over 96% of the area equipped and borderstrip irrigation on about 2%. On the hill slopes the delivery network for the irrigation of gardens and grapes consists of pipes, but the irrigation technique used on the field is also surface irrigation (Figure 6). Micro-irrigation was developed on an experimental basis on 110 ha in 1990, but at present is no longer used.

All irrigation is full-control irrigation. About 68 000 ha are irrigated from groundwater and about 25 000 ha from re-used drainage water and wastewater (Figure 7). To some 250,000 ha, or 34.8% of total area equipped for irrigation, water is provided through pumping in rivers, while elsewhere the water is gravity-fed from river diversion or reservoirs.

In 1994, the total length of the irrigation canal network was about 33,250 km. The length of the main canals and the inter-farm network was 27,991 km, of which 38% consisted of concrete canals. The on-farm canal network totaled 5,259 km, with 13.3% concrete canals, 21.9% pipes and the remaining 64.8% unlined earthen canals (Figure 8). In 1994, the irrigation efficiency, considering losses between the source and the irrigated field, was estimated at 72%.

Large-scale schemes, with an area of more than 5,000 ha, cover 670,000 ha, while small-scale schemes, with an area of less than 5,000 ha, cover the remaining 49,200 ha (Figure 9). No private irrigation systems exist in Tajikistan.

The major irrigated crops are cotton, fodder, fruits and grapes, cereals and vegetables (Figure 10). Cotton, fruits and grapes are the most important export crops. In 1994, irrigated crop yields were 1.91 t/ha for cotton, 0.85 t/ha for wheat, 1.71 t/ha for rice and 3.01 t/ha for grapes.

The costs of irrigation development and rehabilitation are higher in Tajikistan than in downstream countries, mainly because of the need for pumping and erosion control. The average cost of irrigation development is estimated at US$10,000-18,000/ha for large-scale surface irrigation schemes using standard modern technologies, including agricultural development. If micro-irrigation were to be developed on the existing irrigated lands, its estimated implementation cost would be US$2,300-3,500/ha. Annual operation and maintenance (O&M) costs which would enable full cost recovery are estimated at about US$550/ha for gravity surface irrigation systems, US$600/ha for micro-irrigation and US$750/ha for pump systems. However, in recent years the actual operational cost has not exceeded US$120-136/ha.

Waterlogging, salinity and drainage development

Out of the total irrigated area of 719,200 hectares (ha), over 600,000 ha require drainage. However, in 1994, drainage systems had been constructed on only 328,600 ha. Approximately 58% is surface drainage, and 42% is subsurface drainage (Figure 11). The average cost of surface drainage development is estimated at US$500-600/ha, and that of subsurface drainage development at US$1,400/ha. The total length of the existing drainage network is about 11,500 km.

The two major land quality problems in the country are the interrelated issues of salinity and waterlogging, caused by high groundwater levels. In 1994, about 115,000 ha, or 16% of the irrigated land, were classed as saline by Central Asian standards (toxic ions exceed 0.5% of total soil weight).

Institutional environment

The Ministry of Water Resources (MWR) 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 inter-farm level. Water distribution is based on a strict limitation of water withdrawal. Water allocations are regularly reduced to promote water savings and to satisfy the demand from new users. Institutionally, water management follows a hierarchy: state, province, district, farm (or Water User Associations [WUAs]). The first three levels come under the MWR and are responsible for water distribution and delivery to the farm inlet, for assistance to the water users in implementing advanced technology, and for the control of water use and water quality. The special reclamation services at provincial level are the responsibility of the MWR. They monitor the irrigated lands (groundwater level, drainage discharge, soil salinity) and plan measures for the maintenance and improvement of soil conditions, including leaching, repair and cleaning of collectors and drainage network, and rehabilitation.

The Ministry of Agriculture is in charge of agricultural research and extension, agricultural and land reclamation development at farm level, and operation and maintenance of the irrigation network at farm level.

The state enterprise `Tajikjilkomkhoz' is responsible for domestic water supply and the treatment of wastewater. The Ministry of the Environment is responsible for the protection of water resources.

The water law and water rights are defined by the special `Water Code of Tajikistan', which was confirmed on 12 December 1993.

Tajikistan is a member of IFAS and ICWC. Within Tajikistan are the Leninabad board of the Syr Darya BWO and the Kurgan Tube board of the Amu Darya BWO.

Trends in water resources management

Tajikistan has developed two alternative scenarios in its national water strategy, the main objective of which is water conservation.

Under the first scenario, the irrigated area in 2000 will be the same as in 1994, 719,200 ha, while in 2010 it will be 743,000 ha. The main goal during the next 15 years will be the rehabilitation of the existing irrigated land and a reduction in irrigation water demand from 11.23 km3/year in 1995 to 9.81 km3/year in 2010. The irrigated area per capita is expected to fall from 0.12 ha to 0.08 hectares (ha), which will not be able to satisfy the growing demand for food. In the other sectors, water consumption is expected to increase: municipal demand from 0.48 km3 in 1995 to 0.60 km3 in 2010, industrial water demand from 0.5 km3 to 1.5 km3. The total water withdrawal is assumed to remain more or less stable, or even to decrease slightly during the next 15 years.

Under the second scenario, the irrigated area will be 755,200 ha in 2010, while water withdrawal will fall from 11.23 km3/year at present to 10.38 km3/year in 2010. The total water withdrawal is assumed to increase by about 0.7-0.8 km3/year.

The environmental problems in Tajikistan are the result of its climate and natural conditions (steep slopes) and the structure of the national economy. The irrigated area is subject to substantial erosion, land slides, sagging and deformation. The area affected is estimated to be about 45,000 ha. Irrigation development in the foothill zone, especially in the more stony areas, induces increasing groundwater recharge, intensifying waterlogging and salinization of the lower areas, and increasing the sediment-loaded drainage water runoff. Collector-drainage water is the principal water polluter (common mineralization, pesticides and some other waste ingredients). Environmental pollution is also increasing as a consequence of industrial production.