变异系数法评价人类活动对地下水环境的影响

北京市平原区地下水系统可以分为6个子系统.由于各子系统的水文地质条件不同,人类活动对其影响程度也不同.为评价人类活动对各子系统的影响,以2011年9月地下水样品数据做基础,选取水质相对较差的第一和第二含水层组为评价层位,考虑总硬度、溶解性总固体、硫酸盐、氨氮等13项人为活动影响指标,采用变异系数法确定各指标的权重,以及参考国标确定各指标评价分值的方法,叠加计算各水样的综合分值,评价平原区地下水水质状况.以地下水子系统为评价单元,以各类型水质分区为评价要素,对比分析各子系统受人类活动影响程度.评价结果表明,人类活动对第一含水层组的影响大于第二含水层组,永定河地下水子系统和潮白河地下水子系统受影响大于其他地下水子系统.

Influence of Human Activities on Groundwater Environment Based on Coefficient Variation Method

Groundwater system in the plain area of Beijing can be divided into six subsystems. Due to the different hydrogeological conditions of the subsystems, the degrees to which human activities affect the subsystems are also diverse. In order to evaluate the influence of human activities on each subsystem, the first and second aquifer with relatively poor water quality were chosen to be the evaluating positions, based on the data of groundwater sampled in September, 2011. With respect to human activities affect index such as total hardness, TDS, sulfate and ammonium, variation coefficient methods were used to calculate the weight of each index. Then scores were obtained for each index with national standard as reference, and superposition calculations were used to gain comprehensive scores, finally the groundwater quality conditions were evaluated. Contrast analyses were used to evaluate the incidence of human activities with groundwater subsystems as evaluation unit and water quality partitions as evaluation factors. The results indicate that the influence of human activities on the first aquifer is greater than that of the second aquifer, the Yongding river groundwater subsystems and the Chaobai river groundwater subsystems are affected more than other groundwater subsystems.