The River Nura in Kazakhstan

Kazakhstan is the largest state in Central Asia and the largest landlocked country in the world. The central Kazakhstan plain occupies an area of some 200 000 km² and is rich in mineral and coal resources. The area belongs to the dry steppe zone and is characterised by low undulating hills covered with sparse grassland and drained by seasonal rivers. There are few perennial rivers, and more than 80% of their flow occurs during the spring thaw. The climate is sharply continental, with cold winters, hot summers and little precipitation.

The 978 km long River Nura is the main river of the central Kazakhstan region. It rises in the Karkaralinsk mountains in the east of the country and flows westward through the heavily industrialised Karaganda region before entering the terminal lakes and wetlands of the internationally important Kurgaldzhino nature reserve. In administrative terms, the Nura is part of the Nura-Sarysu river basin, one of eight major river basin divisions in Kazakhstan. The Sarysu River is located in the arid south of the region and only has surface flow in spring. The two river systems are connected via the non-operational Nura-Sarysu canal. The Nura catchment alone covers 55,000 km², excluding the area of Lake Tengiz in the terminal wetlands.

Near the Nura lie many of the cities and large population centres of Central Kazakhstan, such as Karaganda, Astana, Temirtau, Shakhtinsk, Abay, and Saran. The largest cities are Karaganda and Temirtau which grew in response to the industrial development associated with coal and iron deposits and steel making. Although the population has declined considerably over the past 15 years due to a general decline in industrial activities, Karaganda is still the second largest city in Kazakhstan. About 300 km further downstream lies Astana, the new capital city since 1997. The population of Astana is expected to increase significantly over the next decades, and the Nura has been considered the most likely future source of water for the city.

At present the water resources of Central Kazakhstan are supplied by a complex and interconnected system of hydro-engineering structures and mainly depend on surface water (Figure 1). A significant proportion of the industrial water demand used to be supplied by the 458 km long Irtysh-Karaganda Canal which transfers water from the River Irtysh in the north-east to the Nura near Karaganda, via 14 dams and 22 pumping stations, lifting the water up a total of 418 m. Opinions are divided on whether the canal is a viable option for the long-term water supply of Karaganda and Temirtau and the water security of Astana, however. Water quality is thought to be poor, pumping costs are high, and there are major losses from infiltration and evaporation.

There are two major reservoirs on the Nura, Samarkand reservoir in Temirtau, and the unfinished Intumak reservoir, located about 75 km further downstream. A third reservoir is located on the Sherubainura, the largest tributary to the Nura which joins the river about 30 km south-west of Temirtau. Together they have a total volume of more than 500 million cubic metres. Apart from the large reservoirs, there are about twenty smaller reservoirs on the Nura and its tributaries with a total useable volume of 100 Mm³, and more than two hundred ponds with a total capacity of about 50 Mm³. The average annual discharge of the Nura is 5.9 m³/s just upstream of Temirtau, and 19.6 m³/s near Astana. Because of the climate of the region the majority of surface flow occurs as snowmelt in the spring. The current estimated water demand in the Nura basin, not considering the demand of Astana, is in excess of 220 Mm³/year.

Close to Astana the Nura comes within 25 km of the River Ishim, which has an average annual flow three times smaller than the Nura. A link canal was constructed between the Nura and the Ishim and was intended to supply additional water to Astana, but was closed at the end of the 1980s because of concerns over a mercury spill which polluted the Nura upstream near Temirtau. The canal was reopened for agricultural use in 1999, and a project to clean up the Nura in the most polluted section has recently been initiated by the World Bank.

About 150 km south west of Astana, the Nura discharges into the Kurgaldzhino wetlands and Lake Tengiz , one of the most important wetland sites in Central Asia which is currently being considered as a UNESCO World Heritage Site. Nearly 300 species of birds have been recorded at Lake Tengiz; many of them are endangered. Breeding species include the Greater Flamingo (Phoenicopterus ruber), Dalmatian Pelican (Pelecanus crispus) and White-headed Duck (Oxyura leucocephala). More than 80% of the 258,000 ha Kurgaldzhinsky Nature Reserve is covered with water, and Lake Tengiz, the largest lake in the system, covers 160,000 ha. Despite its importance, almost no research has been carried out on the Tengiz-Kurgaldzhino lake system , and the water requirements of the area are unclear. The impact of changes in the river abstraction regime and water quality on the wetlands remains to be assessed, particularly in view of the fact that Astana plans to take 25% of the mean annual flow of the Nura.