南水北调中线工程通水后郑州市地下水埋深变化研究

Study on Variations of Groundwater Depth in Zhengzhou City After Operation of Middle Route Project of South⁃to⁃North Water Diversion

为了评价南水北调中线工程通水对郑州市地下水埋深的影响,采用地统计学方法和主成分分析法,分析南水北调中线工程通水后郑州市5个城区浅层和中深层地下水埋深时空变化及影响因素。结果表明:南水北调中线工程通水后,浅层地下水埋深空间相关性随时间呈减弱趋势,空间变异性主要受结构因素的影响;中深层地下水埋深的空间相关性随时间明显减弱,由强烈相关减弱为中等相关,且随时间推移,小尺度随机因素发挥的作用越来越大;2015—2019年,研究区地下水位有不同程度的回升,枯水期浅层地下水平均埋深减小0.63 m、丰水期减小2.37 m,地下水埋深为10~20 m的分区面积明显增大,地下水埋深大于40 m的分区面积明显减小;枯水期深层地下水平均埋深减小5.15 m、丰水期减小21.04 m,地下水埋深小于40 m的分区面积明显增大,地下水埋深为40~60 m的分区面积明显减小;影响浅层和中深层地下水埋深变化的因素为调水量、开采量、用水量和降水量,南水北调替代水源对研究区地下水位稳定恢复起到主导性作用。

In order to evaluate the influence of the Middle Route Project of South⁃to⁃North Water Diversion on groundwater depth in Zheng⁃zhou City,taking the shallow and middle⁃deep groundwater depth of Zhengzhou City as the research object,this paper studied on the changes of the shallow and middle⁃deep groundwater depth of Zhengzhou City and affecting factors based on geostatistics,Kriging interpolation and principal component analysis after the operation of the Middle Route Project of the South⁃to⁃North Water Diversion was completed.The results show that the spatial correlation of shallow groundwater depth decreases with time.Spatial variability of shallow groundwater depth is mainly affected by structural factors.The spatial correlation of middle⁃deep groundwater depth decreases obviously with time,and the correlation gradually decreases from strong to medium.With the passage of time,the role of small⁃scale random factors affecting the spatial variation of deep groundwater depth is becoming more and more obvious.Groundwater level in the study area rebounds in varying degrees.The average depth of shallow groundwater decreases by 0.63 m in dry season and 2.37 m in wet season from 2015 to 2019.The area of 10-20 m buried depth increases obviously,and the area of more than 40 m buried depth decreases obviously.The average depth of deep groundwater decrea⁃ses by 5.15 m in dry season and 21.04 m in wet season.Distribution area of buried depth less than 40 m increases obviously,and distribution area of buried depth 40-60 m decreases obviously.The main factors affecting shallow and deep groundwater depth are water diversion,ex⁃ploitation,water consumption and rainfall.The water resources substitution policy has played a dominant positive role in the recovery of shal⁃low and meddle⁃deep groundwater levels.