黄土区长武塬地下水埋深动态特征及影响因素分析

Dynamics of Groundwater in Changwu Loess Tableland and Its Determiants

【目的】明确地下水补给机制并指导地下水资源合理开发。【方法】基于1976—2017年长武塬区5眼监测井的地下水埋深数据,分析了地下水埋深动态变化,并利用互相关和多元线性回归等方法识别地下水埋深的影响因素。【结果】长武塬区地下水埋深介于25~95 m之间,各井因水文地质和人为干扰程度等差异表现出不同的波动特征。地下水埋深总体呈波动下降趋势,降幅介于0.08~0.21 m/a。气象因子、植被和人为因素在年内或年际尺度对地下水埋深都有一定影响,但主导性不同。年际尺度,人为因素主导地下水埋深变化,贡献率达74%。年内尺度,植被是影响地下水埋深的主要因素,贡献率为40%。【结论】人口、GDP和苹果园面积的增加对地下水埋深影响较大,需要考虑人类活动与水资源间的可持续性。

【Objective】Groundwater is the predominant water resource for agricultural and other sectors in the loess tableland in northwestern China. Understanding its response to management and environmental changes is important to elucidate the mechanisms underlying groundwater recharges and help improve groundwater resource management. The purpose of this paper is to present a method to analyze the determinants of groundwater change in the loess tableland. 【Method】The analysis is based on data measured from 1976 to 2017 from five boreholes in the Changwu loess tableland. Change in groundwater depth and its determinants are identified using the crosscorrelation and multiple linear regression methods. 【Result】The groundwater depth in Changwu varied between 25 and 95 m, with the variation depending on boreholes due to the difference in hydrogeological conditions and human activity between them. On average, the groundwater table had fallen from 1976 to 2017 at 0.08-0.21 m/a,with the falling rate depending on boreholes. Meteorology, vegetation and anthropogenic activities are the factors affecting both monthly and inter-annually change in groundwater depth, though the relative dominance of these factors varies with boreholes. Interannually, anthropogenic activities affected groundwater more, contributing to 74%of its depth change. Monthly, vegetation was the factor predominantly affecting groundwater, contributing to 40% of its depth change. 【Conclusion】Increase in population, economic development and expansion of apple orchards is the factors underlying the groundwater depth change in the studied area. Our results have an important implication for sustainable development of agriculture and other industries sectors in this region.