昌平区山前平原地下水位空间变异性特征分析  

Spatial variability of groundwater levels of piedmont in the Changping District

作　　者：顾晓敏[1] 崔亚莉[1] 肖勇[1] 郝奇琛[1] 

机构地区：[1]中国地质大学(北京)水资源与环境学院,北京100083

出　　处：《水文地质工程地质》2015年第2期10-15,23,共7页Hydrogeology & Engineering Geology

基　　金：国家重点研究基础发展计划"973"项目(2010CB428804)

摘　　要：基于Arc GIS的地统计模块和半变异函数模型,在了解昌平区山前平原水文地质条件的基础上,选取30眼地下水位观测井2001—2011年间水位观测数据分析地下水位的空间变异性。利用交叉验证法遴选最优半变异函数模型,结合空间插值分析对未知点进行无偏最优估计。结果表明,北京市山前平原的最优插值模型为0阶球状模型,插值方法选用析取克里格方法;2011年地下水位的块金效应为0.45,受地形起伏、降水以及水文地质条件等因素影响较大,空间相关性强,而地下水降深的块金效应达到0.969,表明人类活动和测量误差等因素对其影响较大,空间相关性弱;由块金效应可知2001—2011年间人为大量开采使地下水位的空间相关性逐年减弱;受到水文地质条件和人类活动的共同影响,地下水流主径流方向上的块金效应为0.34;由于人类大量开采,冲洪积扇中上部地下水位空间变异性变化更为显著,在顶部和下缘空间变异性较小。克里格空间插值结果可为今后开采井的合理布设及进一步研究人类活动影响下地下水系统变异规律提供依据。The Arc GIS Geostatistical module is used to analyze spatial variability of groundwater levels from 2001 to 2011 with 30 observation wells. Based on the hydrogeological conditions,the cross-validation method is used to choose the best-fit model to eatimate the spatial interpolation of the unknown points. The results show that the best model the for the interpolation is the 0 order spherical model for the disjunctive Kriging method and the nugget effect of groundwater level is 0. 45. The structural factors such as topography and rainfall have more influence on the nugget effect,and the spatial correlation of the nugget effect and the structural factors is obvious. The nugget effect of groundwater drawdown is as high as 0. 969,and the measurement error and other random factors have a greater effect on the nugget effect and the spatial correlation is weak. From 2001 to 2011,the nugget effect of groundwater level is increasing,indicating that groundwater overexploitation makes the spatial correlation weaken gradually. The nugget effect of the trend direction is 0. 34,indicating the influence of random factors by directly removing the structural factors. The kriging spatial interpolation results show that due to the combined effect of the hydrogeological conditions and human activities, the spatial variability of groundwater drawdown is larger in the upper part of the alluvial fan and small in top and bottom. The results can provide a basis for monitoring wells layout and a further study of the groundwater system.

关 键 词：山前平原 地下水位 地统计 空间变异 

分 类 号：P641.12[天文地球—地质矿产勘探]