The effects of runoff on Hydrochemistry in the Qilian Mountains: a case study of Xiying River Basin

摘要

With the increase of water consumption and deterioration of water quality in the arid region of China, attention has been raised on issues such as the selection of water sources, water resources protection and water source protection. Based on the surface water samples of Xiying River Basin in the upper reaches of Shiyang River from June 2015 to May 2016, the sampling period is once a month for 1 year. At the same time, combined with the same-day runoff and precipitation data of Nine Ridges Hydrological Station at Xiying River outlet, the influence of runoff process on Hydrochemistry in Xiying River upstream was analyzed using Piper triangle diagram, Gibbs diagram and PCA. The results show that: (1) The surface water is generally weak alkaline, mainly enriched with Ca2+ and HCO3-, and the water type is generally Ca-HCO3. (2) The seasonal variation of inorganic ion concentration is very obvious. Ion concentration is high in winter and spring, but low in summer and autumn. (3) Because erosion and transport of rock weathering by runoff process are the main source of runoff ion, the ion concentration in watershed water varies significantly in space, gradually enriched with altitude from high to low, especially Ca2+, HCO3-. (4) Ion concentration is positively correlated with precipitation and negatively correlated with runoff in the same period.