基于GIS的河北平原地下水位时空变化动态分析

根据1975、1980、1985、1990、1995、2000年的地下水位观测资料，利用GIS技术，采用Kriging插值方法，分析了近25年来河北平原地下水位的动态变化过程，揭示了地下水位的时空演变规律，并探讨了地下水位下降的原因。1975-2000年，河北平原浅层地下水位下降10．2m，年均下降速率为0．41m／a，其中以1990—1995年下降速率最大，达0．74m／a。深层地下水位下降30．2m，年均下降速率1．21m／a，其中以1980—1985年下降速率最大，达1．83m／a。在区域分布上，自山前平原至滨海平原，浅层地下水位和下降幅度逐渐减小，而深层地下水位和下降幅度逐渐增大。降水和地表径流的减少以及地下水的严重超采是引起地下水位下降的主要原因。

GIS-Based Analysis on Spatio-Temporal Change of Groundwater Level in the Hebei Plain

Based on the data of the depth to groundwater table below land surface with observational wells in 1975,1980,1985,1990,1995, 2000 of the Hebei Plain, adopting GIS technic and Kriging interpolation method, this paper analyzes the spatio-temporal change of groundwater level in the past 25 years in Hebei Plain. The depth to shallow groundwater table below land surface has fallen 10.2?m during 1975-2000 and the annual average decline of groundwater table was 0.41 m. The annual average decline rate of groundwater table during 1980-1985 and 1990-1995 was the largest, with 0.7?m/a and 0.74?m/a respectively. The depth to deep groundwater table below land surface has fallen 30.2m in the past 25 years and the annual average decline of groundwater table was 1.21?m. The annual average decline rate during 1980-1985 was the largest, with 1.83?m/a. The shallow groundwater table and the decline rate decrease from the Piedmont Plain to the Coastal Plain, while the deep groundwater level and decline rate increase from the Piedmont Plain to the Coastal Plain. The decrease of precipitation and surface water and over-exploitation are the main reasons that result in groundwater level decline.