USING STABLE ISOTOPE ANALYSIS TO CHARACTERIZE THEHYDROLOGY OF TURPANBAISIN, WEST CHINA

摘要

Water scarcity is most acute in arid and semi – arid regions that cover almost one third of the Earth’s land surface.rnMoreover, limited fresh water resources available in these regions are also threatened with deterioration in quality due to man –rninduced hydrological changes. The available water resources in arid regions are often restricted to groundwater.rnAnalysis of stable isotope in groundwater and surface water in Turpan Basin, West China was carried out to identify therngroundwater origin. Turpan Basin is hydrogeologically divided two parts, which is a North Basin and South Basin. The analysis datarnof stable isotope δD and δ18O in groundwater shows a systematic decrease identified from mountain hill to the basin along therngroundwater flow direction. The δ18O value ranged from – 9.5 ~ – 11.8‰ and ranged about 2.3‰. The isotope variation is consistentrnwith higher altitude recharge following flow paths along north – south trending rivers in the upper basin and systematic decreased inrnthe lower basin. All of the water samples besides the lake water were plotted above the global meteoric water line with highrndeuterium excess. It indicates that, the groundwater in the basin is different with the meteoric water.rnThe kariz drainage system of Turpan Basin in the lower part of Tianshan Mountains is used extensively for irrigation andrndrinking water supplies. The management of this water resource requires an understanding of the main processes controlling therngroundwater evolution and the origin of the exploited waters.rnRecent investigations show that recharge in semi arid and arid areas is episodic, and there is no linear correlation between annualrnprecipitation and recharge (Zhu, 2000).rnThis paper focuses on the groundwater – surface water relationship in basin and mountain area under controlling of the variousrnhydrologic conditions. The main objective of the present study is origin of groundwater in the kariz drainage system within thernframework of its unique complex geology and morphology using stable isotopes.