密怀顺地区生态补水对地下水水化学的影响分析

Analysis on the influence of ecological replenishment on groundwater hydrochemistry in Mihuishun area

基于北京市密怀顺地区2019年3月至2021年12月外源水及地下水质监测数据,综合运用水化学分析方法,分析了不同外源水生态补水对地下水水化学的影响;同时,采用离子比例关系图和水文地球化学模拟软件(PHREEQC)进行地下水化学的成因分析。结果显示,南水各离子浓度较低,再生水中各离子浓度显著高于南水与地下水。外源水入渗对地下水水化学的影响表现为水化学类型逐渐向外源水靠近,研究区中部地下水在南水影响下水质变好。研究区生态补水时,主要受混合与方解石溶解沉淀作用影响。研究区南部地下水在引温济潮再生水影响下,发生脱硫酸作用,使得SO42-降低,方解石的沉淀量增加,明显改变地下水演化。

Based on the monitoring data of exogenous water and groundwater quality in Mihuishun District of Beijing from March 2019 to December 2021,the effects of ecological replenishment of different exogenous water on groundwater hydrochemistry were analyzed by comprehensive application of hydrochemical analysis methods.At the same time,the genetic analysis of groundwater chemistry was carried out by using ion proportion diagram and Hydrogeochemical simulation software(PHREEQC).The results showed that the concentration of ions in the southern water was lower,and the concentration of ions in the regenerated water was significantly higher than that in the southern water and groundwater.The influence of exogenous water infiltration on groundwater chemistry shows that the type of water chemistry gradually moves closer to exogenous water,and the groundwater in the middle of the study area affects the groundwater quality better in the south.The ecological water replenishment in the study area is mainly affected by mixing and calcite dissolution and precipitation.In the southern part of the study area,under the influence of reclaimed water from Wenji-tidal drainage,desulphurization and acid action occurred,which reduced SO2-and increased the precipitation of calcite,significantly changing the evolution of groundwater.