In July 2005 IWMI initiated studies on Ground water management for improved irrigation in Syrdarya river basin within Fergana valley. The project funded by OPEC. The Syrdarya river is one of the two main rivers of the Aral Sea basin. The Republics of Kyrgyzstan and Tajikistan are located in the upstream, Uzbekistan in the middle stream and Kazakhstan at the tail end of the river. During the Soviet time, irrigation of lands was based mainly on water withdrawal from the river and its tributaries. 

With the collapse of the Soviet Union and creation of independent states, the operation regime of the upstream reservoir has become an issue, since the priorities and national interests of the new states were not always congruent. These contradictory interests of up and middle stream countries and the discharge of water from the upstream reservoirs in winter period for power generation, has resulted in flooding in the middle stream and accumulation of significant amount of water in the natural depression Arnasai. More than 40 km3 of fresh water is already in the Arnasai depression. This artificial lake has become a source of destabilization with respect to the natural environment over a large area. At the same time amount of river flow available for irrigation of summer crops is reduced significantly.  Irrigation water deficit was recorded in Central Fergana, Syrdarya and Djizak provinces of Uzbekistan and southern Kazakhstan in 2000-2002.

To reduce losses occurring due to flooding of the highly productive land and to preserve available water in the dry season, Uzbekistan has been considering several options including the construction of reservoirs for deregulating of the river flow. However, there are several negative consequences may arise from the construction of the reservoirs including flooding of highly productive irrigated soils, further increases in ground water table and waterlogging. Ground water development for irrigation in Fergana valley is one of the alternatives, can significantly reduce demand to withdraw water from the river during the summer time and increase available flow for middle and down stream water users. These studies were initiated in Fergana valley within Uzbekistan. Ground waters within irrigated zone of Fergana valley have relatively low salinity level and considered to be the good source of water for irrigation.

Regional benefits of ground water management will include the following:

• reduced demand for river flow during summer months in the specified ground water active management areas;
• increased available flow from Syrdarya river for middle and downstream water users;
• reduced drainage water outflow from the area; reduced ground water salinity;
• improved quality of river’s water supplied to water users in the middle and downstream;
• increased power generation in the upstream.

The specific objectives of these studies are:
A. Identify suitable areas for ground waters development in Fergana valley within Uzbekistan;
B. Modelling of the ground water pumping for irrigation using MODFLOW;
C. Evaluation of economics of ground water development for irrigation under different scenarios.

GIS will be used to assess ground water resources available for irrigation within Fergana valley.  MODFLOW will be applied for detail modelling of ground water resources development in the basin of Sokh, tributary of Syrdarya within Fergana province. Economics of conjunctive use of ground and canal waters will be determined under different policy strategies. The IWMI, in collaboration with Uzbekistan Hydrogeology Service, Syrdarya Basin Water Organization and Tashkent Institute of Irrigation and Melioration implements these studies.