基于GMS的兰州“三滩”水源地地下水水质演化及调控对策

Evolution and countermeasures of water quality of the Santan wellfield in Lanzhou based on GMS

为解决兰州"三滩"傍河水源地的咸水污染威胁,在对研究区地下水污染调查的基础上,以研究区地下水系列监测资料为依据,利用地下水数值模拟软件GMS建立了研究区地下水流和溶质运移耦合模型,设计三个水源地地下水资源开采和管理方案,模拟预测其水量恢复效果以及对南侧咸水的阻隔效应。结果表明,若维持现状开采,傍河区地下水位会上升,水质在变好,但南河道以南地下水溶解性总固体逐渐升高,南部咸水会慢慢向水源地迁移。若马滩水源地部分井群恢复开采,南河道以北地下水溶解性总固体有降低趋势,但微咸水和淡水的混合界面将向北迁移。若打通南河道,且马滩水源地部分井群恢复开采,受黄河水和南河道入渗双重补给,傍河区以及南河道北侧地下水溶解性总固体会持续降低,南河道南侧的微咸水体也会有所淡化。恢复南河道是改善和恢复水源地的有效途径。

The Santan riverside well Field（ SRWF） faces the threat of intrusion of salty groundwater. Based on an investigation of groundwater pollution in the study area and the series of groundwater levels and chemistry monitoring data,we develop a coupling model of groundwater flow and solute transport with the GMS software to resolve this problem. Three groundwater management scenarios are designed and the changes in groundwater levels and water quality are modeled. The results show that if the current groundwater pumping scheme does not change,the water levels along the bank of the Yellow river will rise,and the water quality will meliorate,but TDS of the groundwater in the south of the South River Channel will arise,because the salty water in the south of the wellfield will intrude into the well field. If part of the pumping wells in the Matan wellfield is restored,the TDS of the groundwater in the north of the South River Channel will decline,but the salty water will also intrude into the wellfield. If the South River Channel is dredged and connected with the Yellow river,and part of the wells in the Matan wellfield resumes their production,the TDS of the groundwater from the Yellow River across the north of the South Channel will decline,which is resulted from the recharge of the Yellow River and the South Channel,and the brackish water in the south of the South Channel will also be diluted. In general,resuming the South Channel is an effective way for the resuming and improvement of the water productivity of SRWF.