GROUNDWATER CIRCULATION PATTERNS IN KASHGAR DELTA, XINJIANG, CHINA

作者：Wei, Xing; Zhou, Yinzhu; Zhou, Jinlong^*; Zeng, Yanyan; Zhang, Jie

来源：FRESENIUS ENVIRONMENTAL BULLETIN, 2022, 31(6A): 6461-6470.

• Hydrogeochemistry
• Environmental isotope
• Groundwater age
• Renewal rate
• Groundwater circulation pattern

The Kashgar Delta in Xinjiang, China, is a semi-closed basin facing a challenge of a prominent "quality-induced" groundwater (GW) shortage. This study used hydrogeochemistry and environmental isotope techniques to delineate GW circulation patterns of the region. The results indicated that: (1) The direction of evolution of GW hydrochemistry is HCO3 center dot SO4-Ca -> SO4-Ca -> SO4 center dot Cl- Mg center dot Na -> SO4 center dot Cl-Na and salinity gradually increases from upstream to downstream. The piedmont sloping alluvial-diluvial plain and the river alluvial plain represent the dissolution-runoff zone and the runoff-accumulation salt zone, respectively; (2) GW ion composition is mainly affected by the dissolution of rocks and evaporation, whereas confined GW of the river alluvial plain is affected by reverse cation exchange and mixing; (3) The H-3 age of GW ranges from 8 to 49 a and exceeds 50 a in some areas. The rate of groundwater renewal ranges from 0.03%.a(-1) to 16.35%.a(-1). The C-14 age of GW ranges from 476 a to 34,578 a; (4) GW circulation patterns can be divided into two local circulation systems (I-1 and I-2) and a regional circulation system (II). I-1 has a younger GW age and a faster renewal rate than I-2. The GW age and renewal rate of I-2 gradually increases and decreasing along the GW flow path, respectively whereas II has a large circulation depth, a long runoff path, old GW, and weak renewability.