北京市南部平原区地下水位及开采强度时空演变趋势分析

Analysis of Spatial and Temporal Evolution Trend of Groundwater Depth and Exploitation Intensity in Southern Plain Area of Beijing City

为了解南水北调水入京后对北京市南部平原区地下水位埋深的影响,以北京市大兴区为例,通过收集该区域2010~2020年的地下水位埋深监测数据及用水量数据,采用地统计方法对2010~2020年的地下水位埋深进行了时空变异性分析,并进一步采用主成分分析法评价了该时段的地下水开采强度。结果表明,南水北调入京后,区域地下水位埋深呈减小趋势,2015~2020年相比2010~2014年,地下水位平均埋深由19.13 m减至17.67 m,说明南水北调入京后,对区域地下水位的恢复具有明显的正向效应;基于地统计半变异函数模型计算南水北调入京前后地下水位埋深的块金效应值,发现2015~2020年与2010~2014年相比,地下水位埋深的块金效应值由55.92%减至39.05%,说明人为因素对地下水位埋深的影响处于减弱的状态;基于主成分分析法计算了2010~2020年对地下水开采强度的影响变化,表明区域用水对地下水开采强度的影响总体呈减小趋势,其中工业用水量、第三产业用水量及农业用水量对地下水开采强度的影响处于减小趋势,生活用水量对地下水开采强度的影响处于增大趋势。研究结果可为南水北调沿线区域的地下水资源管理提供理论和方法借鉴。

In order to understand how the South-to-North Water Diversion Project has influenced the groundwater depth across the southern plains area of Beijing, this study collected the groundwater depth and water consumption measurements over the period of 2010-2020 in Daxing District. The geostatistical methods was carried out to analyze the spatial-temporal variability of the groundwater depth, and a principal component analysis(PCA) was used to evaluate the groundwater exploitation intensity over the period. The results show that the water diversion project has been putting the groundwater depth on a decline, reducing the average from 19.13 m over 2010-2014 to 17.67 m in 2015-2020, indicating a significantly constructive influence toward the groundwater depth recovery in the region. The nugget effect values of the groundwater depth, as calculated using the geostatistical semi-variogram model, dropped from 55.92% in 2010-2014 to 39.05% in 2015-2020. This decline indicates the weakening influence of human factors toward the groundwater depth. The PCA calculations show that the effect of regional water consumption on groundwater extraction intensity decreased from 2010 to 2020. Water consumption in industries, tertiary industries, and agriculture contributed to this tendency, while domestic water consumption stimulated groundwater extraction intensity. The findings turn out to be reliable theoretical and methodological references for groundwater resource management toward the regions along the water diversion routes.