三江平原典型区地下水流场变化及主要影响因素分析

为了进一步探明三江平原地下水流场变化及主要原因，本文以三江平原典型区为研究区，分析了2001—2019年地下水流场变化情况，基于地下水位变化空间差异，采用交叉小波分析、皮尔逊相关分析和灰色关联度分析等方法，定量研究了降水及地下水开采对不同区域地下水位的影响程度。结果表明：研究区2001—2019年间地下水大体流向未发生明显变化，但地下水位呈现整体下降趋势，下降区域面积为1.86万km~2,占整个研究区的83.97%,地下水位的整体下降与水田面积迅速扩张有关。水位上升区地下水位与降水在年周期上存在显著共振关系，二者皮尔逊相关系数为0.485,而水位与地下水开采间不存在稳定的周期性相关，相关性较差；中东部水位明显下降区地下水位与降水之间不存在稳定的周期性相关，相关性较差，而水位与地下水开采在年周期上存在显著共振关系，二者皮尔逊相关系数为-0.409。研究区中部地下水位大幅下降区域水位受地下水开采影响程度明显大于受降水影响，灌区内地下水位小幅下降区域水位受地下水开采影响程度略大于受降水影响。本研究对于深入探究区域地下水资源变化和指导该地区地下水资源合理开发利用具有重要意义。

Analysis on variation of groundwater flow field and its main influencing factors in the typical district of Sanjiang Plain

In order to further investigate the variation and main causes of the groundwater flow field in the Sanjiang Plain, the typical district of the Sanjiang Plain was carefully selected as the research area. This paper analyzed the variation of the groundwater flow field from 2001 to 2019, and based on the spatial difference of groundwater level changes, the Cross Wavelet Transform, Pearson Correlation Analysis and Grey Correlation Analysis were used to quantitatively study the influence of precipitation and groundwater exploitation on the groundwater level in different regions. The findings reveal that the overall groundwater flow direction of the study area did not change significantly from 2001 to 2019, but groundwater levels in most areas decreased, and the area of decreased region was 18,600 km², accounting for 83.97% of the total study area. The rapid expansion of the paddy field was responsible for the overall decline in groundwater levels. There is a significant resonance relationship between groundwater level change and precipitation in the annual cycle in the water level rising area, the groundwater level lags about 11.52 days relative to the precipitation, and the Pearson Correlation Coefficient between them is 0.485; but there is no stable periodic correlation between groundwater level and groundwater exploitation in this area, and the correlation is poor. There is no stable periodic correlation between groundwater level change and precipitation in the central and eastern part of the study area where the groundwater level drops significantly, and the correlation is poor; but there is a significant resonance relationship between groundwater level and groundwater exploitation in the annual cycle in this area, the variation in groundwater level lags behind the variation in groundwater exploitation by about 10. 8 days, and the Pearson Correlation Coefficient between them is -0.409. The groundwater level is significantly more affected by groundwater exploitation than by precipitation in the central part of the study area where the groundwater level drops sharply. Though the water level in the irrigation area where the groundwater level drops slightly is more affected by groundwater exploitation, it is also greatly affected by precipitation. This research is of great significance for conducting in-depth investigations of regional groundwater resources changes and guiding the rational development and utilization of groundwater resources in this region.