基于随机森林的黑河中游地下水埋深变化及成因

研究黑河中游地下水埋深变化规律及其成因，可为该流域地下水合理开发利用提供参考。根据黑河中游33个观测井1985—2010年的地下水埋深资料，利用地统计学方法分析了地下水埋深变化规律；采用随机森林法研究了埋深变化的成因。结果表明:黑河中游地下水埋深自南向北减少；甘州区和临泽县的地下水埋深变化趋势分别在2001年和2004年前呈增大趋势，之后又逐年减小，高台县北部地区埋深呈持续减小趋势，而东部地区呈增大趋势；地统计学分析表明地下水埋深具有中等的空间相关性，且空间各向异性有增强的趋势；影响黑河中游地下水埋深变化的主要因素是渠系水利用系数、地下水开采量、地表水引用量及蒸发能力。

Change of Groundwater Depth and Its Causes in Middle Stream of the Heihe River Basin Based on the Random Forest

In order to provide useful references for the reasonable development and utilization, the distribution characteristics of groundwater depth and its causes in middle stream of the Heihe River Basin was examined. Based on the local groundwater depth data of 33 observation wells from 1985 to 2010, the spatiotemporal distribution characterisitcs of the groundwater depths were analyzed by using the geostatistics. The random forest method was used to investigate the change causes of groundwater depth. The results showed that the groundwater depths of the middle stream of the Heihe River Basin reduced from the south to the north. Before 2001 in Ganzhou District and 2004 in Linze County, the groundwater depths had an increase trend, respectively, afterwards both reduced. The groundwater depth of the northern Gaotai County presented the continuous decrease trend, but groundwater depth of the eastern Gaotai region increased. Moreover, according to the analysis of geostatistics, the sample of the groundwater depths had spatial correlations with middle-level, and its spatial anisotropy had enhancement tendency. In addition, the main factors influencing the groundwater depth in the middle stream of the Heihe River Basin were the utilization coefficient of canal system water, the exploitation quantity of the groundwater, surface water diversion quantity and evaporative capacity.