北京平原区地下水水质监测网优化设计

Optical design of monitoring network of groundwater quality in the Beijing Plain

文章分析了北京地下水水质监测和水质变化的历史和现状。应用DRASTIC评价方法对平原区进行了易污性评价并获得易污性分区图。叠加地下水易污性分区图、地下水价值分区图和地下水源保护区图生成地下水保护紧迫性分区图。编制了地下水污染源分布图。合并地下水保护紧迫性分区图和地下水污染源分布图获得地下水污染风险分区图。以地下水污染分区图指导地下水水质监测网的设计,调整地下水水质监测孔的密度。优化后的北京平原共有监测孔538眼(组),其中分层监测井136眼(组),新设计监测孔343眼。结合地区地下水水质年内变化规律调整监测频率。建议浅层极易污染区每年丰枯期各取1次样,其它地区每年枯水期取1次样。承压水每2年在枯水期取1次样。

This paper analyzed the history and current status of groundwater quality and monitoring in the Beijing Plain. The DRASTIC approach was used to assess the vulnerability of groundwater to pollution. The results show that the majority of the Beijing Plain is vulnerable to pollution. Groundwater vulnerability map, groundwater value ratings and groundwater protection areas were combined to create a groundwater protection urgency map. Major groundwater pollution sources were identified and mapped. The product of groundwater protection urgency and pollution sources ratings resulted in a groundwater pollution risk map. This map was used to locate the important sites for groundwater quality monitoring. The newly designed network consisted of 538 monitoring wells, of which 136 are multiple aquifer monitoring wells. 343 new monitoring wells are needed to install for monitoring groundwater pollution. Sampling frequency was determined according to the temporal changes in groundwater quality.