珠江河口区地下水盐分空间变异特征分析

珠江河口区沿海冲积平原水动力条件差，随着几次海进海退的过程，地下储藏着大量的咸水。本文以广州南部地区地下水盐分为研究对象，以物探技术为主要方法，结合地下水TDS空间分布以及14C，分析地下水盐分的变异特征，并探讨了地下水盐分的来源以及珠江河口区地下水循环过程。结果表明:地下水盐分由研究区东部和西部向内陆减少，由北部向南部逐渐增高；地下水溶解性总固体（TDS）超过1 g/L的咸水分布面积约占研究区的75%；研究区地下水流场可分为两个子系统，南部受到海水入侵影响，地下咸水水力交换较差，北部咸水受到地表淡水和浅层地下水的补给后出现淡化现象。

Characterization of groundwater salinity spatial variation in the Pearl River estuary

With the processes of ancient sea transgressions, a large amount of salt water has been stored in the subsurface of the Pearl River estuary due to its low hydraulic conductivities in the coastal alluvial plain area.In this paper, we analyze the spatial variation and the source of groundwater salinity, and discuss the process of groundwater circulation in the Pearl River estuary area, using geophysical prospecting technology, total dissolved solid (TDS) and 14C data.The results of geophysical prospecting show that the groundwater salinity decreases from the east and the west of riverside to the inland, and gradually increase from the north to the south of seaside.The salt water is distributed around 75% of the study area where TDS exceeds 1g/L.The groundwater flow field could be divided into two subsystems.The groundwater flow system in the north is desalinated by receiving surface freshwater and shallow groundwater recharge, while the system in the south is affected by the seawater intrusion and the hydraulic exchange of the subsurface salt water is poor.