Characteristics And Affecting Factors Of Hydrochemistry In Yushugou River Basin,Hami,Tianshan Mountains

As the fastest and most sensitive natural recorder of global climate change,glaciers have important effect on local climate,ecological environment,water resources and chemical components.The runoff reginal of glacier meltwater is the main water source for industrial and agricultural production and urban life in Hami Prefecture,which plays an important role in the development of national economy and society in Yushugou River basin of eastern Tianshan Mountains.Affected by the arid climate,the problem of water shortage has been restricting the economic development and urban construction in this area.Studying the ionic composition and control mechanism of water is a great significance for understanding the geological conditions,natural weathering of rocks and soil,regional environmental evolution trend and the degree of human influence on water quality in the northwest arid region.Therefore,this paper selects Yushugou River Basin of Tianshan Mountains as the research area.A scientific field investigation was accomplished between April and August 2018.The samples involve snow,glacial meltwater,precipitation,river and groundwater.The hydrochemical characteristics of different water bodies and the controlling factors of ions source were systematically analyzed using mathematical statistics,hydrochemistry?Gibbs graphic method,Piper graphic method?,model calculation?Environmentfactors,EF,Forward Direct method?,etc.The results show that:The pH of all water bodies in Yushugou River Basin is range from 6.8 to 8.0,the precipitation and glacier water are neutral,and the river and groundwater are weakly alkaline.The ionic concentration of water bodies is consistent with EC,that is,groundwater>river>precipitation>glacier snow>ice surface runoff.Ca²⁺is the most dominant cation in all water bodies,HCO₃^-is the dominant anion in surface water and groundwater,and SO₄^2-is the dominant anion in precipitation and glacial water bodies.The hydrochemical types of groundwater and surface water are Ca²⁺-Na⁺-HCO₃^--SO₄^2-,precipitation hydrochemical type is Ca²⁺-Na⁺-SO₄^2--NO₃^-,and glacial water chemical type is Ca²⁺-Na⁺-SO₄^2--Cl^-.The ionic concentration of precipitation,surface water and groundwater showed obvious difference in season,that is,the ionic concentration was higher in spring and lower in summer.However,individual ions in water bodies such as NO₃^-and NH₄⁺show the opposite characteristics.Ions in precipitation are mainly controlled by terrestrial sources,such as regional dust,salt lake particles and local rocks and minerals,while Marine and artificial sources have little effect on them.More than 90%of Ca²⁺come from the land,97%of NO₃^-come from anthropogenic input,Cl^-mainly comes from sea salt,Na⁺,Mg²⁺,K⁺mainly come from the land,followed by the marine input.Mineral rock and soil weathering are the main factors controlling the chemical composition of surface water and groundwater.Carbonate rocks and feldspar minerals are the main sources of ions in surface water and groundwater.The contributions of different sources to river chemical ions are obviously different,and the contribution rate is:carbonate rock>silicate rock>atmospheric>artificial.Carbonate rocks are dominant in all sources of river chemical composition in this basin,with an average contribution rate is more than 60%,and the contribution rate of anthropogenic to ions in river is the lowest.Anthropogenic inputs have obvious seasonality.