Abstract: The spatial distribution of groundwater hydrochemical components plays a crucial role in effectively managing and safeguarding groundwater resources. Based on hydrochemical composition data obtained from the Shaliu River basin of Qinghai Lake in different typical months, we investigated the spatial distribution and heterogeneity of major groundwater hydrochemical components including anion content, pH value, and total dissolved solids (TDS) by using geological information system (GIS) spatial analysis. The findings of this study are summarized as follows: 1) Different months exhibited significant variations in the spatial distributions of anions and cations. The discrepancies in ion distributions were more prominent in June compared to January and October. Compared to January, June experienced a decrease in the extent of high-value regions for the concentrations of K⁺, Na⁺, F^-, and SO₄^2-, while an expansion in the high-value regions for Ca²⁺, Mg²⁺, and HCO^-₃. Conversely, the high-value and low-value regions for NO^-₃ content underwent no substantial changes. In October, the high-value regions for Ca²⁺, Mg²⁺, NO^-₃, and HCO^-₃ content further shrank compared to June, whereas the high-value regions for K⁺, Na⁺, F^-, and SO₄^2- contents expanded.During the study period, the spatial distribution of Cl^- concentration did not change significantly. 2)The main cations in the Shaliu River basin of Qinghai Lake were affected by carbonate weathering, while silicate weathering was observed in the lower reaches of the basin. 3) Most ions in the basin roughly converged from the middle and upper reaches of the basin to the estuary, and then dispersed to the estuary delta.

Key words: shallow groundwater, hydrochemical composition, spatial distribution, Shaliu River Basin, Qinghai Lake