M. Bauer

Presentation at the EURO-ECO Symposium 2007 “Ökologische und Technologische Aspekte der Lebensversorgung”, to be held on 4 and 5 December 2007, Andor Hotel Plaza, Hannover

Central Asia still remains as an area of substantial water stress problems caused by climate change, over-consumption of water resources and soil salinisation. The rapid recession of glaciers along with a concurrent increasing frequency and intensity of extreme droughts lead to a progressive reduction of the already scarce resources.

As in many other arid and semi-arid zones, surface waters in Central Asia are heavily regulated by extended river-reservoir systems, affecting both the quantity and the quality of water. In this context the large dams and reservoirs of the Amu Darya basin should be considered as an option to adapt to climate and global change and to the future water shortage in the region.

Their important role in the water supply as well as their potential for acting as an essential instrument to support the improvement of the livelihood is shown by past investigation results of the Water Management Center (WMC).

Especially the newly developed method of enhanced reservoir operation provides thereby an applicable and suitable approach for transferring into practice.

The main aspect of this method is to operate the reservoir (inflow) technically according to the quality level of the river water chosen, for example related to chosen quality parameter like salinity. Reservoir filling, storage and release will be altered in time and volume according to defined quality thresholds and only water of acceptable quality will be stored.

The Kaparas reservoir in Uzbekistan located in the lower Amu Darya Basin is one of four interconnected reservoirs of the Tuyamuyun Hydro Engineering Complex (THC) provides needed technical facts for applying the proposed method as it is an off-stream reservoir, not directly placed in the course of the river and further independently controllable.

The results of the study clearly demonstrate that the applied method of enhanced reservoir operation can help to improve the status of the reservoir water body in a convincingly way and serves thereby for the improvement of the water supply. Especially in dry years and times of drought the reduction of the water deficit is of immense relevance. The application of the introduced approach can lead to a reduction of the water deficit in dry years just under 12%.