地下水流场的时空演变特征及驱动力分析

Characterization of time-space evolutionand analysis of driving forces of groundwater flow field

本文采用小波分析方法研究了1965-2013年地下水流场演变特征的时空变化,同时分析了地下水位与其驱动力的相关性。最后,采用PSO-PPM模型识别了驱动力在各水文地质单元中的贡献。研究结果表明,在过去几十年气候变化和过度开发的背景下,研究区地下水位急剧下降;降水量与地下水位有很强的相关性,尤其是在汛期;不同水文地质地区地下水位对降水的敏感性不同;随着开采量的增加,地下水位呈指数函数下降趋势,而在地下水源中,地下水位与开采量呈负线性相关;驱动力的相对贡献随水文地质条件而变化;开采是地下水位变化的主导因素,降水次之,径流对沿江地区地下水位也有较大的影响。

In this paper,the time-space changes in the evolutionary characteristics of the groundwater flow field from 1965 to 2013 are studied using wavelet analysis,and the correlation between the groundwater level and its driving force is also analyzed.Finally,the PSO-PPM model was used to identify the contribution of the driving forces in each hydro-geologic unit.The results of the study show that,in the context of climate change and over-exploitation in the past decades,groundwater levels in the study area have declined dramatically;there is a strong correlation between precipitation and groundwater levels,especially during the flood season;the sensitivity of the groundwater levels to precipitation varies in different hydro-geologic area;the groundwater level tends to decrease as an exponential function with increasing extraction,while in groundwater sources,the groundwater level is negatively and linearly correlated with the amount of extraction;the relative contribution of driving forces changes with hydro-geologic conditions;mining is the dominant factor in groundwater level changes,followed by precipitation,and runoff also has a large impact on groundwater levels along the river.