ENVIRONMENT AND SECURITY
Geographic and hydrological features The Amu Darya extends over 2 54010 km, making it the longest river in Central Asia. Known as the Oxus in the Greek world and the Jayhun in the Arab world, it has marked the history of the region for centuries. Since ancient times the Amu Darya has not only been the source of life for vast arid lands but has also served as a border and a line of communication11.
feeds the Wakhan River, both of them eventually form the Amu Darya. After leaving the highland zone, the river veers northwest to cross the arid Turan Plain, where it forms the boundary between the Karakum and Kyzylkum Deserts, located respectively to the southwest and northeast. The river’s lower reaches form part of the boundary between Uzbekistan and Turkmenistan.
The Amu Darya is formed by the confluence of the Vakhsh and Panj Rivers12 and flows west-northwest to its mouth on the southern shore of the Aral Sea. Not far below this junction the Amu Darya is joined by additional major tributaries: on the left bank by the Kunduz River and on the right by the Kafirnigan Rivers.
Topography, glaciers, precipitation patterns and climate variability are the important factors which greatly influence the flow of water in the Amu Darya basin, which consists of three main zones: an upstream mountainous zone – the mountains of Pamir-Alai and Hindu Kush13 rising to 7 495 metres generate 90 per cent of the flow; a midstream region – with several distinct large irrigated oases; and a downstream zone14 of flow depletion with a delta and discharge into the former Aral Sea. The latter two zones consist mainly of deserts, fragments of grassland, arid forests and plains at elevations no greater than 300-500 metres.
In its upper reaches the Amu Darya forms part of Afghanistan's northern border with Tajikistan, Uzbekistan, and Turkmenistan. The melting snow and glaciers of the Alai Valley of Kyrgyzstan contribute water to the Vakhsh (KyzylSuu) River, whereas the Wakhan Corridor of Afghanistan
The Amu Darya basin The Amu Darya River basin area and its socio-economic and geographic definitions vary widely depending on the source of data and application. From the hydrological point of view, the upstream catchment area of the Amu Darya River basin contributing water to the main river is 309 000 km2 at Kerki gauging station in Turkmenistan. This includes a large part of Tajikistan (except its northern Sogd province and the Markansu-Tarim basin), the southwest corner of Kyrgyzstan (the Alai Valley) and the northeast corner of Afghanistan. If the mid and down-stream sections of the potential drainage area in Turkmenistan and Uzbekistan are included, the total catchment area varies from 465 000 km2 to 612 000 km2, depending on the source of data15. On average, available water resources in the Amu Darya basin are estimated at 78 km3 a year for surface water and up to 25 km3 a year for groundwater. The live storage capacity of the man-made reservoirs in the Amu Darya basin amounts to 20 km3. The basin's water resource availability fluctuates from 58 to 109 km3 a year16. The long-term average flow of the main Amu Darya17 is about 62 km3 a year (2 000 m3/sec) at Kerki18.The actual flow depends on the climatic conditions in the current year. The amount of snow, spring rainfall and the intensity of glacier melt in summer play a decisive role in the formation of water resources, when flow significantly increases19 and in extreme cases causes flooding. If the major irrigation canals, collectors, small rivers, aquifers and springs related to the Amu Darya basin but not discharging water into the main Amu Darya River are included, the greater Amu Darya basin area amounts to 1.3 million km2 including a large part of Turkmenistan, more than half of Uzbekistan and a fraction of Iran. The definition of the greater basin was used by the Soviet Union and is still commonly used in regional water affairs and international literature, however, as we shall see below, regional water management pays little attention to the Afghan part20. While small and marginal areas of the Amu Darya basin are important, the present report focuses on the four countries which hold the lion’s share: Afghanistan and Tajikistan (upstream), Turkmenistan and Uzbekistan (mid and down-stream). 14