华北平原地下咸水垂向变化及机理探讨

Discussion of vertical variations of saline groundwater and mechanism in North China Plain

为探讨华北平原地下水开采对供水安全的影响和地下水水质的变化趋势,采用地下水水质动态监测、地面物探现场试验和成井物探等大量的实测资料验证地下水咸水下移的事实,并从水文地质条件、地下水位下降和地下水开采利用状况等方面,对咸淡水界面下移的机理进行分析。结果表明：咸淡水界面从20世纪70年代以来下移约10-20 m,开采地下水造成上下层水头压力变化是其主要原因之一。

In order to investigate the effect of groundwater exploitation on water supply safety and the patterns of groundwater quality,the fact that saline groundwater moved downwards was proved by a large amount of field data collected through dynamic monitoring of groundwater quality,in situ testing of geophysical prospecting,and well geophysical prospecting.The mechanism of downward movement of the in terface between the fresh and saline groundwater was analyzed in terms of hydrogeological conditions, the water table＇s descent and groundwater exploitation conditions. The results show that the amount of descent has been about 10-20m since the 1970s, and one of the main reasons for the pressure head change in both the upper saline and lower fresh groundwater was exploitation of groundwater.