穆兴平原北部地下水年龄及更新性

地下水年龄结构是了解一个地区地下水资源开采可持续性的重要基础。穆兴平原地下水开采量增加以及地下水环境恶化,对该地区可持续发展有一定制约,为此在2016年采集CFCs样品31组和3H样品60组,估算了研究区地下水年龄。结果表明,穆兴平原北部地下水年龄为21年到大于65年,由西北部和穆棱河向平原中部及乌苏里江逐渐变老,更新性变差,主要受到大气降水和地表河水补给,但是由于地表覆盖一层黏性土,地下水中缺失小于10年的水;不同井深样品中二者及NO_3~-浓度的变化,表明在60 m以上地下水的防污性能较差,而在100 m以下则较好,饮用水源井深需超过100 m。

Groundwater age and renewability in the north of Muling-Xingkai plain

The age structure of aquifer is an important basis for understanding the sustainability of groundwater exploitation. Increasing groundwater pumping with deteriorate groundwater environment in the Muling-Xingkai Plain (MXP) has restricted to some extent the sustainable development of the region. 31 groups of CFCs and 60 groups of ³H samples were collected to delineate groundwater flow systems. Estimated groundwater age ranges from 21 years to more than 70 years in the northern part of the MXP. Younger water occurs in northwest piedmont and hilly areas as well as Muling River, while older water occurs in the central part of the plain and the Wusuli River. This reflects long flow paths associated with regional flow. Although groundwater is mainly recharged by rain and surface water, ground water younger than 10 years was not found for the unsaturated zone consisting of silty clay. The variations of ³H and CFCs combined NO₃^- with wells depth indicate that the aquifer sensitivity of groundwater system above 60m is low and it is high below 100m. Wells for drinking water should exceed 100m.