某河流冲洪积扇地下水水质特征及演变趋势研究

Research on Groundwater Quality Characteristics and Evolution Trend of the River Alluvial Fan

某河流流域灌区地下水水质变化规律和分布特征的研究对指导当地生产及提高地下水利用水平有重要的实践意义.通过对该流域洪积扇地下水水样进行阴阳离子测试,利用Piper三线图对地下水进行分类,并运用Phreeqc程序对洪积扇区地下水水-岩作用进行模拟计算.结果表明:冲洪积扇扇顶戈壁砾石平原区和扇中砾石平原区地下水以重碳酸-硫酸-氯化物-钙、镁型水为主,扇缘细土平原绿洲区地下水以硫酸-氯化物-重碳酸-钙、镁型水为主,局部地段为重碳酸-硫酸-氯化物-钙、镁型水和氯化物-硫酸-重碳酸-钠、钾型水;洪积扇区地下水水-岩作用较为活跃,水化学组分离子主要来自石膏、硬石膏、岩盐、Ca(OH)_2和MgCO_3等矿物的溶解.

It is instructive to research the groundwater quality characteristics and evolution trend in the irrigated area of the river basin which is essential to guide manufacture and raise groundwater utilization ratio.This paper classifies the groundwater samples of the river alluvial fan through anionic and kation test and Piper trilinear nomograph then simulate the water-rock interaction by program Phreeqc.The results show that multitude of groundwater chemical type is HCO 3-SO 4-Cl-Ca.Mg in the Gobi gravel plains area at the middle-upper of alluvial fan;SO 4-Cl-HCO 3-Ca.Mg type is mainly with HCO 3-SO 4-Cl-Ca.Mg and SO 4-Cl-HCO 3-Na.K types existing in part areas in the oasis fine soil plain area at the edge of the alluvial fan.Water-rock interaction is active whose ions of hydrochemistry components come from dissolving of gypsum,anhydrite,halite,Ca(OH)2,MgCO 3 and the other minerals.