基于GIS的水源地地下水水质分布规律研究

Research on the distribution of groundwater quality in water source area based on GIS

为查明水源地地下水水质,为拟选水源区地下水资源利用和开发提供重要参考。本文基于水文地质调查的基础,在拟选水源区采集21个水样送检分析,利用ArcGIS软件的地统计分析模块检验水样测试结果后,基于空间插值模块得到八种元素的空间分布特征。同时选取氯化物、硫酸盐、TDS、总硬度4个代表性指标进行地下水水质单因子评价和综合评价,得到水源地地下水水质评价结果和水源区地下质量分布情况。研究发现:拟选水源区地下水多介于4~8 m之间;地下水主要离子的变异系数大小关系为K^(+)+Na^(+)>SO_(4)^(2-)>TDS>Cl^(-)>HCO_(3)^(-)>Mg^(2+)>总硬度>Ca^(2+)>pH;通过选取氯化物、硫酸盐、TDS、总硬度共4项有代表性的指标对地下水质量进行单因子评价和综合评价,单因子评价结果表明地下水中氯化物、硫酸盐、TDS含量符合生活饮用水标准(Ⅲ类),部分水样品中总硬度达到生活饮用水Ⅳ类标准,地下水综合评价结果显示71%的地下水样为良好,29%为较差。

Identifying the quality of groundwater in the water source area provides an important reference for the utilization and development of groundwater resources in the proposed water source area.Based on the basis of hydrogeological survey,21 water samples were collected and analyzed in the selected water source area.The hydrogeochemistry type was analyzed by Piper three-line diagram and ion correlation is analysised by principal component analysis.The geostatistical analysis module of ArcGIS software was used to test the water sample test results.The spatial distribution characteristics of the eight elements are obtained by the spatial interpolation module of ArcGIS.At the same time,four representative indexes of chloride,sulfate,TDS and total hardness were selected to single factor valuate and comprehensively evaluate.The study found that the groundwater level in the proposed water source area is mostly between 4 and 8 m;the coefficient of variation of the main ion of groundwater is K^(+)+Na^(+)>SO_(4)^(2-)>TDS>Cl^(-)>HCO_(3)^(-)>Mg^(2+)>TDS>Ca^(2+)>pH;by selecting a total of four representative indicators of chloride,sulphate,TDS and total hardness for single-factor evaluation and comprehensive evaluation of groundwater quality,the single-factor evaluation results show that the content of chloride,sulphate and TDS in groundwater meets the standard for domestic drinking water(Class III),and the total hardness in some water samples meets the standard for domestic drinking water Class IV.The comprehensive evaluation results of groundwater show that 71%of groundwater samples are good and 29%are poor.