凉水河流域地下水水化学特征和时空变化规律

北京凉水河流域的同位素和水化学特征分析表明:1)地下水水质在100m以浅相对较差,但到2017年为止,水质保持稳定.2)浅层地下水与平原区河水同位素相对富集,且落在同一条蒸发线上;但整体上河水与浅层地下水水化学类型不同,据此推断山前冲洪积扇河水入渗是区域地下水补给的重要来源,下游地下水主要受到侧向径流影响. 3)同位素平衡和质量平衡计算表明人类活动使得河水TDS含量增加了435mg/L,而地下水TDS历史时期的增量也接近.4)山前冲洪积扇河水入渗是区域地下水补给的重要来源,是地下水污染防控和调水工程实施的重点区域.

Hydrolochemical characteristics and spatial-temporal variations of groundwater in the Liangshui River basin,Beijing

We present a case from Liangshui River catchment to investigate and quantify the reasons for these changes. Results indicate that the groundwater with poor quality are limited at depths less than 100m. Shallow groundwater and river samples plot on the same meteoric water line, which indicates river seepage is one of the important controlling factors for groundwater quality. Meanwhile, the hydrogeologic structure of the study area indicates the groundwater is primarily recharged from river seepage in upper alluvial-proluvial plain, which should be considered an important protected region. Antropogenic contamination added about 435mg/L both in the river and shallow groundwater. Although groundwater pollution is observed at shallow depths, the trend is likely in stable state indicated by the steady TDS values over the most recent seven years. In order to mitigate groundwater pollution, limits on pumping phreatic aquifer water and channel anti-seepage treatment measures are put forward for consideration.