Environmental isotope studies on shallow groundwater in the lower Tarim river, Xinjiang

A comparison of isotopic data of shallow groundwater with those of river water and local rainfall indicates that the groundwater of the lower Tarim River directly originates from the river water which is recharged by precipitation and snow-melt waters in mountain areas. The trend lines converge near δD of -7.05% and δ18O of -1.05%, suggesting approximately the original isotopic composition of the river water and shallow groundwater. The steady isotope study shows that the sources of high salinity in the groundwater are mainly high rate evaporation. With the environmental tritium, the groundwater residence time and its mean annual recharge rate have been estimated on the basis of exponential model