Irrigation and Drainage

Agriculture is the largest consumer of water in the Pyanj Basin. The need for irrigation for agricultural production is long-established, with agriculture relying only on rainfall is unreliable and of low productivity. There are rain-fed areas of agriculture in higher lands with poor soils where crops have low water requirements and might fail completely during the long dry summers.

During the Soviet period extensive irrigation systems were built to provide irrigation water to suitable land. Suitable land is mostly found in river valleys, or on terraces formed in earlier geological time along the river valleys. Much of the irrigated land was fed through pumped systems and developed when charges for energy needed to lift water through pumping were negligible.

Since the end of the Soviet period many irrigation systems have fallen into disrepair, especially in those areas fed through pumping stations and pumping cascades. Much of the antiquated electrical and mechanical equipment became inoperable and is slowly being replaced when funds are made available for rehabilitation of systems. The water distribution systems in the lift areas have also become unusable through loss of canalette sections and general abandonment of land once irrigated.

Sources of water for irrigation are very largely river systems – with little groundwater used. River water quality is generally very suitable for irrigation but has a high sediment load mostly. In general, there is plenty of water available for irrigation use, but little land suitable and economic under present conditions for profitable agriculture.

In the Soviet period some of the irrigated areas were also provided with drainage systems. These are usually open channel networks of drains discharging through gravity back into the river system – although some pipe drains are also present. These have had little maintenance since the end of the Soviet period and have become blocked and filled with sediments greatly restricting the capacity of the systems. The reduced performance of the drainage systems has not severely impacted on agricultural production as irrigation water application rates have been restricted in recent times due to issues of maintenance of the supply systems. But with attention given to rehabilitation of irrigation systems there will be a need to provide appropriate improvement in the drainage networks to avoid problems of waterlogging and salinization of the fields.

Management of the irrigation and drainage network to the farm level is the responsibility of the Agency for Land Reclamation and Irrigation (ALRI). At the field level, the organization of Water Users Association in being developed to assume responsibility for management of the tertiary level of irrigation systems, the distribution of water to field outlets, and collection of dues for payment to local ALRI units for water supply.

Monitoring of the performance of the irrigation and drainage systems of the basin has also been problematic since the Soviet period, with reported hydraulic information based on water levels unsupported by actual measurements of flows in the system. In poorly maintained systems, conversion of water levels to estimated discharges is not accurate and can be misleading.

Irrigation Canals

The total irrigated area is 170,142 ha and is divided into 2,452 schemes. Out of these, 2,013 have an area of up to 5 ha and 439 – areas ranging from 5 to 10 ha. The total length of the canals is 7,266 km, of which 206 km are lined. The canals are equipped with 543 structures on the main network and 742 field delivery points. The outlets have a total of 1,206 gauging stations. In addition, there are 6,077 km of operational on-farm canals, of which 104 km are lined.

The Kulyab irrigation system is characterized by long conveyance canal sections and significant water losses due to filtration. The overall system efficiency is 0.58. The intake structure of the Farharo-Chubek irrigation system is located at the head of the “Dekhkanabad” main canal. The efficiency of the unlined irrigation canal network is 0.62.

Table 1: Length of Irrigation Canals in the Pyanj River Basin

Note: There are no inter-farm and on-farm irrigation systems in the Baldzhuvansky and Shamsidin Shokhinsky Districts. The irrigated lands of Temurmalik district are managed by the Vose District of ALRI.

Reservoirs

The use of artificial and natural reservoirs and their maintenance in good technical condition for the basin are of increasing importance. We must make a reservation that the question is being raised about the study of large capacity reservoirs with a volume of 0.02 to 10 cubic km and located in such a way that they can possibly be used for the needs of hydropower and irrigation, or affect this kind of use. Therefore, such reservoirs as Tigrovaya Balka lakes (reserve), Karakul, Shur-Kul and Rangkul in the Murghab district of GBAO are not included in the intended list of reservoirs for study.

Currently, the basin has two reservoirs formed by blockages: Sarez Lake on the Bartang River, Yashil-Kul on the Gunt River. There are two small reservoirs related to irrigation with a volume of 20 to 30 million m³ – Muminobod and Selbur.

The Muminobod Reservoir, commissioned in 1958, is located on the Surkhak River and has a surface area of 7.2 km² and capacity of 25 million m³. The height of the dam is 34 m. The Selbur Reservoir commissioned in 1961 on the Kyzyl-Su River covers a surface area of 2,55 km² and has a capacity of 20 million m³. The dam is 1,040 m long with a maximum height of 132 m.

The number of waterworks with large reservoirs is projected to increase significantly in order to utilize the hydropower potential of the basin. The potential dam sites, most of which were planned for implementation in the next 15-20 years, and the existing ones are presented in the table below. Some of these dam sites are being developed, for example, the Lower Pyanj and the Sarez Lake.

Table 2: Potential Dam Sites in the Pyanj River Basin

Pumping Stations

The basin is sub-divided into three water resource zones: (i) Nizhny (Lower) Pyanj; (ii) Kulyab (Kyzyl-Su, Yah-Su); and (iii) Badakhshan. The main sources of irrigation water in the basin are the Kyzyl-Su, Yakh-Su, Pyanj, Kulyabdarya and also smaller rivers.

Water for about 40% of the irrigated areas of the basin, is supplied using pumping stations (28% of pumping stations are state-owned, 12% have other ownership). There are 73 pumping stations in the basin, including: (i) Lower Pyanj WRZ, state owned – 22, non-state owned – 2; (ii) Kulyab WRZ, state owned – 46, non-state owned – 5; and (iii) Badakhshan WRZ, state owned – 10, non-state owned – 16.

The 1,000 ha of the existing 2,000 ha of irrigated land of the Jamoat “Ozodi” of the Jaikhun District is irrigated with water from the Pyanj River, supplied by a cascade of “Fayzobod Kala” pumping stations of the ALRI Pyanj Administration.

Table 3: Main Features of the Existing Pumping Stations

Drainage Network

The total length of the drainage network in the basin is 2,393.4 km, of which inter-farm – 663.7 km (28%) and intra-farm – 1,729.7 km (72%). The total drained area is 51,391 ha with a drainage network density of 20.2 m/ha.

Another important feature of the drainage network of the basin is that its entire drainage volume is discharged into the Kyzyl-Su, Yakh-Su, Kulyabdarya, Toir-Su Rivers. The “Tigrovaya Balka” drainage flows into the Pyanj River, but currently there is no information about its volume.

Some 82% of the total irrigated area in the Farharo-Chubek system is equipped with drainage. The specific density of the drainage network is 23.77 m/ha and the density of the irrigation network is 33.28 m/ha. Out of the total irrigated area of 38,842 ha, 94% of the soils are not salinized. There are, however, sites with sodium carbonate salinization covering about 461 ha, which require chemical treatment for reclamation.

Table 4: Length of Drainage Network

Irrigated Land

1. The irrigated systems in the basin are located mainly in the Kulyab and lower Pyanj water resource zones, where irrigated areas amounted to 170,142 ha in 2018. The table below presents the recent (2010-2018) expansion of irrigation in the basin.

Table 5: Expansion of Irrigated Land 2010 – 2018

Due to the varying natural characteristics in water resource zones, irrigated land is distributed rather unevenly. Historically, the first irrigation systems were established at the alluvial plains along the Pyanj River (Karadumskii massif). In these systems, mainly gravity irrigation was practiced. The irrigated lands of the hilly zones located beyond these alluvial zones were developed in the Soviet period, as part of large programs for the expansion of agricultural production in the 1960-70s. However, these irrigation systems require pumping to deliver water, sometimes for several stages.

As can be seen from the table below, despite the development of new lands, the average area of available irrigated land has noticeably decreased by 2018 due to high population growth rates, even after some increase of the irrigated land. The most critical is the situation in the Kulyab and Badakhshan zones, where the irrigated land was 0.07-0.08 ha/person.

Table 6: Irrigated Land per Capita (2018)

Land Resources for Expansion of Irrigated Agriculture

The size and distribution of the population in the basin is characterized by a high natural population growth, a positive balance of external migration, and a low mobility of the indigenous population. This explains why, in terms of employment, the basin is generally lagging compared to the rest of the country.^[1] Therefore, the Government of Tajikistan places a high priority to the development of agriculture and specifically of new irrigated agricultural land in this region.

The main criteria for the selection of land for irrigation were the topography, soil properties, availability and distance to the water source, and socio-economic development. The availability of the arable land (394,160 ha) in the basin and a significant number of the working population create favorable conditions for intensification of agriculture by providing irrigation infrastructure. At present, irrigated lands are located mainly in the lower parts of basin and only a smaller part (recently developed) on the upper terraces. Because of this, the further development of irrigation would involve virgin and grazing lands located higher along the sides of these valleys, therefore, the area with pumped water supply would increase.

Some 15% of the irrigated areas in Tajikistan are concentrated in the Kulyab WRZ. The number of irrigated plots with an area up to 5 ha is 1,568, and 280 plots are with an area between 5 and 10 ha. Therefore, in the Kulyab WRZ, besides the main objective – irrigation of the Dangara Valley, irrigation of lands in the Baldzhuvan, Khovaling and Muminabad zones in planned. Development of irrigation in this zone is associated with the construction of the Baldzhuvnsky reservoir, and the second phase of the development of Karadum irrigation system is also planned.

Table 7: Irrigation Areas – Existing and Projected Growth by 2030

Taking into account various scenarios of population growth, and to maintain the average irrigated land per person (0.09 ha/person) by 2030, it is necessary to develop 20,000-20,500 ha of and bring the total irrigation area to 168,500-169,000 ha. Given below are the indicators per person in the basin, taking into account the development of new irrigated lands by 2030, compared to 2018. In the basin, even with the development of new irrigated lands stipulated by the plans, there is a decrease in specific indicators per capita from 0.09 to 0.07 ha. This indicator is the lowest in the Kulyab WRZ of 0.06 ha per person.

Table 8: Irrigated Area per Person

Due to the projected high population growth, in particularly in the rural areas, the process of reducing the per capita area of available irrigated land will also continue. Vast financial resources will be required to develop new irrigated areas, including (i) rehabilitation and modernization of irrigation systems, (ii) procurement of equipment, and (iii) construction new hydraulic structures, canals, reservoirs, pumping stations and pipelines. The operation and maintenance of the new irrigation systems will also require an additional electric power.

Furthermore, it will be necessary to provide additional irrigation water. According to the “Plan for Development of Irrigated Lands of the Republic of Tajikistan,” an expansion of the irrigation area by 20,526 ha is planned in the basin. This will increase the water withdrawals from Pyanj River by 230,000 thousand m³/per annum. In total, water withdrawals amount to some 2,118,796 thousand m³. This emphasizes the need for efficient water application within the current and new irrigation schemes.

Irrigation Water Use and Future Demands

Reportedly, in 2018 the regional ALRI divisions provided water for an area of 147,881 ha. The total volume of water withdrawals for this period amounted to 1,750,080,000 m³, (planned water withdrawal), and 1,888,796, 000 m³ (actual water withdrawal). According to the revised norms for integrated use and protection of water resources of the basin, approved by the Ministry of Water Management of the Tajik Soviet Socialist Republic (SSR) on 02.29.1984, water standards range from 9,500 to 10,660 m³/ha. Thus, the total estimated regulatory water withdrawal for irrigation for the Pyanj Basin in 2030, taking into account the projected expansion of irrigated land, will amount to 1,735,599 million m³/year (see below).

Table 9: Regulatory Irrigation Water Requirements until 2030^[2]

Note: Using water conservation technologies can save up to 10% of irrigation water.

Considering that the total amount of water resources in the basin, taking into account all surface and underground water as well as reuse of drainage water, the required withdrawals appear to be much less that the available water resources in the basin.

Analysis of the retrospective data on use of water resources and the technical condition of water management systems explains the low efficiency of these systems, the inadequate water technology and services provided to agriculture (mainly irrigation), and in industrial and municipal sectors.

The weaknesses of irrigation systems operation and maintenance include, in the first place, inefficient water use at farm level. This calls for introduction of modern irrigation technology, rehabilitation and modernization of the existing I&D networks along with measures for land improvement, the lack of automation and remote control of water distribution, as well as application of institutional and financial improvements.

Furthermore, most of the irrigation networks are not lined, inter-farm and on-farm canals have extensive unlined sections and are not sufficiently equipped with water control and measuring devices. In many of the irrigation systems, only limited number of water intakes, main and distributor canals are meet the technical standards. Almost all irrigation systems have the following drawbacks:

• Excessive length of the irrigation network, variable cross sections and slopes, often; as well as siltation and overgrowing vegetation in canals;
• Numerous field delivery points, fragmentation of irrigated plots, incorrect configuration and insufficient leveling, lack of lining, which causes low efficiency and often, along with the lack of extension services in farms, leads to waste of water.

Based on the assessment of the current state of irrigation systems, and the use of land and water resources of the country, the main following directions for improving the technical conditions and operation of irrigation systems were identified:

• Reconstruction and modernization of the existing irrigation systems, and augmentation of water supply; introduction of automation and remote control of water allocation and management and introduction of improved irrigation technology;
• Improvement of soil condition of existing irrigated lands, rehabilitation of the existing drainage network and construction of new modern drainage systems on irrigated lands, land leveling, and other technologies aimed at improving the quality of irrigated land; and
• Improvement of construction and maintenance practices, provision of maintenance services for the inter-farm network and structures, and optimization of on-farm water management and related extension services.

1. For example, the unemployment rate in the GBAO is 2.5 times higher than the average in Tajikistan. ↑
2. Subject to expansion of irrigated land and the provision of a normative water withdrawals. ↑