河套灌区地下水埋深时空变异特征及其影响因素

选择内蒙河套灌区义长灌域作为研究区,利用研究区67眼监测井的地下水埋深资料,采用传统统计学、地统计学和灰色关联分析法,对灌域1990-2015年地下水埋深的时空变异性及其主控因素进行了分析,结果表明:(1)义长灌域26a来潜水位下降近0.4m,平均下降速率1.6cm/a;(2)义长灌域26a地下水埋深的最优变异函数有高斯、指数和球状模型,以高斯模型为主,区域地下水埋深具有较强的空间相关性,变程多在5～7km;(3)空间插值结果表明,不同时期地下水埋深的空间分布存在一定的差异性,但总体上以1.5～2.5m范围为主,平均占比60%;(4)根据灰色关联分析法和偏相关分析,发现蒸发量和地下水补给量是义长灌域地下水埋深的主要驱动因素。

Study on spatial and temporal variation of groundwater depth and its influencing factors in Hetao Irrigation District

In recent years,due to the irrational utilization of groundwater,soil salinization has occurred in some arid and semiarid regions of China.In this research,the spatial and temporal variations of groundwater depth and its main influencing factors were analyzed from 1990 to 2015 based on 67 monitoring wells in Yichang Irrigation Sub district.Statistical analysis,geostatistics and grey correlation analysis were applied to analyzing these data.The results reveal that:(1) the average phreatic level in Yichang Irrigation Sub-district has dropped by nearly 0.4 m in 26 years,and the average decline rate is 1.6 cm/a;(2) the optimal variogram of groundwater depth in the last 26 years has Gaussian, exponential and spherical model,however,it is dominated by the Gaussian model.The regional variation of groundwater depth has strong spatial correlation,and the variation ranges from 5 to 7 km;(3) the spatial interpolation results show that there has certain difference in the spatial distribution of groundwater depth in different periods,while the overall range is from 1.5 to 2.5 m;with an average proportion of 60%;(4) evaporation and groundwater recharge are the main driving factors for the variation of groundwater depth in Yichang Irrigation Sub-district based on the grey correlation analysis and partial correlation analysis.