50年来华北平原降水入渗补给量时空分布特征研究

针对华北平原水文地质条件复杂,地下水开发利用程度高,地下水位埋深和包气带岩性在时间和空间上差异大的特点,基于大量钻孔和地下水位监测资料,将华北平原划分为4个水文地质单元,以埋深7 m作为降水入渗稳定点,根据各分区的水文地质条件对钻孔岩层赋予入渗系数值,应用加权平均法求得华北平原20世纪60年代、80年代和21世纪初的降水入渗系数分布图.利用华北平原1956-2008年水资源四级区逐月降水量数据,求得华北平原20世纪60年代、80年代和21世纪初各分区单元的降水入渗量.结果表明,50多年来华北平原降水量呈减少的趋势,降水入渗系数呈增加的趋势,降水入渗量呈增加的趋势.3个年代的降水入渗量分别是118.86×108,147.91× 108和174.33×108 m3.

Research on Spatial and Temporal Distribution of the Precipitation Infiltration Amount over the Past 50 Years in North China Plain

In the light of characteristics of North China Plain such as hydrogeological conditions, high degree utilization of groundwater, remarkable differences in buried depth of groundwater, aerated zone and on the basis of large quantities of drilling and groundwater level monitoring data, we divided the North China Plain into four hydrogeological units, considering the depth of 7 meters as the precipitation infiltration boundaries and endowed drilling strata with infiltration coefficient according to the hydrogeological conditions of partitions, and obtained the precipitation infiltration coefficient distribution in the 1960s, 1980s and 2000s using weighted average method. The results indicate that the precipitation infiltration coefficient tends to increase with the decline of groundwater level. Although precipitation has a decrease tendency in nearly 50 years, the precipitation infiltration increased due to the infiltration coefficient. The precipitation infiltration amount were 118.86×10⁸, 147.91×10⁸, 174.33×10⁸ m³ in the 1960s, 1980s and 2000s.