Analysis of the Surface Water Chemical Characteristics Variance in the Beiyunhe River Basin

Abstract：An analytical study on the tendency of the surface water chemical characteristics basin had been carried out by the mathematical statistics,the ternary diagram and the Gibbs diagram,based on the water quality monitoring data in the Beiyunhe River Basin during the period from 1980 to 2009.The results showed that the contents of HCO-3 and Ca2+ in river were relatively stable and their absolute values were lager.HCO-3 and Ca2+ were respectively the most dominant anion and cation,which determined water chemical characteristics.The ion correlation diversity in river was obvious during the 1991's and 2006's.The variability of water chemical characteristics increased with the reason.The natural content of the major geochemical ion varied under the influence of human activity.The variance of ionic strength,Cl-,SO2-4,Na+ and NH+4 showed obvious upward tendency,especially the ionic strength and NH+4.The variance of pH value was steady.HCO-3 and the ratio of total hardness to alkalinity showed slightly downward tendency.The major origin of water ions in the Beiyunhe River Basin was weathering of carbonate rocks.The precipitation inputs and evaporation-crystallization were very weak.