| This paper collected the data of groundwater chemistry samples, groundwater level, and meteorology in the period of2000-2009, to study the groundwater chemistry in the lower reaches of Tarim River. The comprehensive statistical analysis is established on the combined traditional and geostatistical analysis, and it mainly takes multi-angles from horizontal, vertical, time and space. Based on the analysis on the characteristic, type, influencing factor, distribution and temporal&spatial evolution for groundwater chemistry elementary, this paper aimed to reveal the response from the change of groundwater chemistry and salinization to surface water conveyance since the project of ecological water transport in2000in the study area. Firstly, this study applied a comprehensive quantitative approach including statistical, principal component and gray relation analyses to assess the groundwater chemistry. Secondly, in the view of traditional statistics, it discussed the differences of groundwater chemistry among different sites or different groundwater level or different time. Thirdly, in the basis of geostatistical analysis, this paper created a space-time model for groundwater salinization, and mainly focused on the spatial and temporal variability and spatial regularity of salinization in the lower reaches of Tarim River. This research can help arid and semi-arid areas to better control the spread of soil salinization, and provide a wise reference to improve local people’s living conditions and ecological environment conditions. The main findings were:(1)There were six types of groundwater chemistry in the lower reaches of Tarim River where Cl· SO4Na· Mg was the dominant type accounting for73.57%in all samples.(2) The groundwater is alkalesscence with pH as7.66, and there were linear relationships among chemical parameters, where TDS had significant multiple correlations with Na+, K+, Mg2+, Ca2+and Cl-, respectively.(3) Three principal components (PC1, PC2and PC3) were extracted, standing for comprehensive measurements for salinization, alkalinity and pH, respectively.(4) Most parameters showed decreasing trends during the period of2000-2009, as well as the scores on PC1, for the reason that the concentrations of various chemical substances were diluted by the uplift of the groundwater table in the lower reaches, since the implementation of the ecological water delivery project in2000.(5) In the middle part of the study area, site B, C, D, E and F had the similar groundwater chemical properties, and site A in the upper and site I in the lower showed larger differences.(6) HCO3-was the most sensitive chemical parameter affected by the groundwater table followed by TA, Mg2+,TH, SO42-,K+, TDS and TS. PC2was the most sensitive principal component to the change of the groundwater table followed by PC1and PC3.(7) The value of groundwater level and TDS led a rising trend, and the latter is faster than the former. Due to the complex influencing factors, the spatial and temporal variabilty of TDS is more strongly than the change of groundwater level.(8) Groundwater level had a more significant correlation than TDS, but the variogram of them were all belong to spherical model.(9) Based on the co-kriging method, this paper obtained the interpolation map of spatial distribution for groundwater salinization status year by year, which combined with groundwater the TDS, groundwater table and elevation of section monitoring. Moreover, crosscheck confirmed the availability of the method.(10) For the time scale, the salinization pollution of the entire study area is serious, indirectly reflecting that the impact from human activities is more serious than the dilution to the lower reaches of Tarim River. For the spatial scale, the TDS in the middle and lower part is higher than the other areas. |
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