Economic costs of reduced irrigation water availability in Uzbekistan (Central Asia)

Reduced river runoff and expected upstream infrastructural developments are both potential threats to irrigation water availability for the downstream countries in Central Asia. Although it has been recurrently mentioned that a reduction in water supply will hamper irrigation in the downstream countries, the magnitude of associated economic losses, economy-wide repercussions on employment rates, and degradation of irrigated lands has not been quantified as yet. A computable general equilibrium model is used to assess the economy-wide consequences of a reduced water supply in Uzbekistan—a country that encompasses more than half of the entire irrigated croplands in Central Asia. Modeling findings showed that a 10–20 % reduction in water supply, as expected in the near future, may reduce the areas to be irrigated by 241,000–374,000 hectares and may cause unemployment to a population of 712–868,000, resulting in a loss for the national income of 3.6–4.3 %. A series of technical, financial, and institutional measures, implementable at all levels starting from the farm to the basin scale, are discussed for reducing the expected water risks. The prospects of improving the basin-wide water management governance, increasing water and energy use efficiency, and establishing the necessary legal and institutional frameworks for enhancing the introduction of needed technological and socioeconomic change are argued as options for gaining more regional water security and equity

Water supply and ancient society in the Lake Balkhash Basin: Runoff variability along the historical Silk Road

Expansion of agricultural practices from the Fertile Crescent to China during the mid and late Holocene are believed to have shaped the early network of Silk Road routes and possibly regulated the dynamics of trade and exchange in the urban oases along the Silk Road throughout its existence. While the impacts of climate change on the Silk Road are more or less documented for the medieval period, they remain poorly understood for early history of the Silk Road, especially in Central Asia. We analyze hydroclimatic proxies derived from fluvial stratigraphy, geochronology, and tree-ring records that acted on various time scales in the Lake Balkhash Basin to learn how changes in water supply could have influenced the early farmers in the Semirechye region of southern Kazakhstan. Our approach aims to identify short-term and long-term variability of regional runoff and to compare the hydrological data with cultural dynamics coupled with the archaeological settlement pattern and agricultural production. The reconstructed runoff variability underscore the contribution of winter precipitation driven by the interaction between the Arctic oscillation and the Siberian High-Pressure System, to Central Asian river discharge. We show that Saka people of the Iron Age employed extensive ravine agriculture on the alluvial fans of the Tian Shan piedmont, where floodwater farming peaked between 400 BC and 200 BC. The early Silk Road farmers on the alluvial fans favored periods of reduced flood flows, river stability and glacier retreat in the Tian Shan Mountains. Moreover, they were able to apply simple flow control structures to lead water across the fan surface. It is very unlikely that changes in water supply ever significantly constricted agricultural expansion in this region