Determination of Groundwater Recharge Mechanism Based on Environmental Isotopes in Chahannur Basin

Abstract

In recent years, the lake area of the Chahannur Basin has been decreasing, leading to an increase in salt dust storms. In order to find out the recharge mechanism of groundwater in the Chahannur Basin, a total of 51 groundwater and surface water samples were collected. Tritium (3H) isotope and Freon (CFCs) were used to estimate the age of groundwater and preliminarily analyze the sources of groundwater recharge. The characteristics of hydrogen, oxygen, and strontium isotopes are used to indicate the characteristics of the water cycle in the Chahannur Basin. The results show that: (1) Two dating methods, tritium isotope (3H) and Freon (CFCs), are suitable for semi-quantitative dating of groundwater in the Chahannur Basin. (2) Hydrogen, oxygen, and strontium isotopes can be used to characterize the groundwater cycle in the Chahannur Basin. (3) The groundwater level around the Chahannur Lake area is low, and the groundwater in the Chahannur Basin flows from the southwest and northwest to the lake area. (4) The groundwater in the Chahannur Basin is mainly replenished by atmospheric precipitation, and the evaporation of groundwater and surface water is strong. The research results provide a basis for the study of measures to prevent the reduction in the Chahannur watershed area.