文登区浅层地下水化学演化与海水入侵研究

Study on the hydrochemical evolution of groundwater and seawater intrusion in the shallow layer of Wendeng District

作者采用水化学演化图(hydrochemical facies evolution diagram,HFE-D)和海水入侵地下水质量指数(GQISWI)对山东威海文登区地下水的化学演化和海水入侵情况进行了分析。Piper图的结果表明文登区从北到南地下水的化学组成分别是Ca-HCO_(3)、Ca-Mg-Cl、Na-Cl。HFE-D表明沿海地区的含水层中海水占主导地位,并且地下淡水补给不足,无明显淡化趋势;内陆地区含水层中的淡水多数处于海水侵入期,有咸化趋势。运用GQISWI、地理信息系统和空间插值法结合,得到了文登区浅层海水入侵现状图。另外,作者考虑渗透系数对离子浓度的影响,运用反距离加权插值算法并结合渗透系数分析了文登区浅层地下水海水入侵程度。结果表明文登沿海地区已经发生了极其严重的海水入侵现象,结合HFED可知咸水有向内陆继续扩散的趋势。研究结果对文登区地下水资源的利用和海水入侵的防治具有重要意义。另外本文是HFE-D和GQISWI在国内文献中的首次应用,为国内其他地区的海水入侵评价提供了参考。

The use of groundwater resources in the coastal zone is affected by seawater intrusion.In this paper,the hydrochemical facies evolution diagram(HFE-D)and groundwater quality index for seawater intrusion(GQISWI)are used to analyze the hydrochemical evolution of groundwater and the current status of seawater intrusion in the shallow layer of Wendeng District.The Piper diagram results show that from north to south,the chemical composi-tions of groundwater in Wendeng District are Ca-HCO_(3),Ca-Mg-Cl,and Na-Cl.The HFE-D indicates that the sea-water in the coastal aquifer dominates,and there is no significant trend of desalination because of insufficient freshwater supply;moreover,most of the freshwater in the aquifers in inland areas is in the phase of seawater in-trusion,and there is a tendency of salinization.Furthermore,GQISWI,geographic information system,and spatial interpolation are used to obtain the status map of seawater intrusion in the shallow layer of Wendeng District.In addition,we use the inverse distance weighting algorithm,considering the influence of the permeability coefficient on the ion concentration,to analyze the degree of groundwater seawater intrusion in the shallow layer of Wendeng District.The results show that extremely severe seawater intrusion had occurred in the coastal area of Wendeng District.The results in combination with the HFE-D result show that the saltwater tends to continue to spread inland.The results of this study are of great significance to the utilization of groundwater resources and the prevention of seawater intrusion in Wendeng District.Moreover,this paper presents the first application of HFE-D and GQISWI in domestic literature and thus provides a reference for the assessment of seawater intrusion in other regions of China.