Chemical Characteristics Of Jinghe River And Analysis Of Its Influencing Factors

Surface water and groundwater are important components of the water cycle.The water chemistry ion is an important tracer in the water cycle which can effectively reveal the characteristics of the water chemistry and analyze the source of ions.Heihe River and its groundwater are the main drinking water,agricultural and industrial water sources in the area.However,in recent years,with the development of the economy and the influence of human activities,the water chemistry of the watershed has undergone different degrees of variation with time and space.The environmental pollutants in some sections were significantly exceeded and it is worth noting that the mining activities in the upper and middle reaches of the river basin are intensive.Therefore,comprehensively understanding and mastering the impact of environmental change on water chemistry is an important prerequisite for the sustainable management of water resources within the loess range.Through the collection of different types of water samples in the Heihe River Basin,Using mathematical statistics,triangular graph and main ion concentration change map to analyze the basic characteristics of basin water chemistry,the type of water chemistry and the trend of ion changes in the sample process respectively,TDS spatial variation,the surface water and groundwater ion content of the basin,Gibbs diagrams and human activity end-member maps were used to analyze ion space changes,compare the relationship between surface water and groundwater and the main factors affecting the source of hydrochemical ions accordingly.Otherwise,the specific source of ions was analyzed using correlation analysis,cluster analysis,and factor analysis.The main conclusions are as follows:1?Through sampling of surface water and groundwater during the dry season and flood season from 2014 to 2016,337 water samples were analyzed.The pH values of surface water and sewage in the Heihe River Basin averaged 8.6 and 7.7,respectively,both of which were slightly alkaline.The dominant cation is Na⁺,accounting for42%⁵8%of the total cation;the dominant anion is HCO₃^-,accounting for 44%⁴6%.The mean surface water TDS was 287.3 mg.L^-1,and the average groundwater level was352 mg.L^-1.It was low salinity water.From dry season to flood season,the surface water chemical type is changed from Na-Mg-Cl-SO₄ type to Ca-Mg-HCO₃ type,and the groundwater is changed from Mg-Cl-SO₄ type to Ca-Na-HCO₃ type is due to the decrease in runoff and precipitation in the dry season.2?In the change of time,the mean concentration of surface water and groundwater in the dry season was higher than that in the flood season,with no significant change between years.Spatial changes,from the upstream to the downstream,the surface water TDS in the dry season increases up to the peak in the upstream,and after the middle and lower reaches,the TDS increases slightly with the river,and the groundwater TDS slowly increases from the upstream to the downstream with the river.Smaller.The change of surface water and groundwater during flood season is similar to that of groundwater during dry season.3?In terms of time,the water quality in each period was in the range of 86.7-100%in the I-III category.The overall water status of the flood season was better than that of the dry season in the same year.In the same year,the groundwater was generally better than the surface water.In terms of spatial changes,surface water:During the dry seasons of 2014 and 2015,the water quality in the upper and middle reaches changed greatly,while the water quality during the dry season in 2016 was higher.The change in the middle reaches is gentle but the level of water quality has decreased slightly in comparison with the previous two years,and fluctuations in the water quality in the downstream have fluctuate greatly.Groundwater:In addition to good water quality in both periods in 2014,the I-III waters are 100%,and the surface water changes in 2015and 2016 are similar to the same period.4.The dominant factor that controls the chemical composition of river water is rock weathering.Evaporation also plays an important role in the formation of river water chemistry parameters.The specific quantification is that the input of rock salt weathering input is 89.6⁹3.4%,and the proportion of atmospheric input is 6.5⁸.6%.The change during the year is that the dry season is greater than the flood season,and the artificial input contribution rate ranges is 0.1¹.8%.