基于Visual MODFLOW地下水数值模拟的水源地保护研究

Research on water source protection based on Visual MODFLOW groundwater numerical simulation

明确地下水运移条件是城市地下水水源地保护的基础。为确保沈阳市某地下水源地的可持续开发,依据沈阳市某地下水水源地的水文地质条件,构建了研究区水文地质概念模型和地下水数值模型,采用Visual MODFLOW软件对模型进行求解,并基于大量监测井水位数据对模型进行参数的识别和验证。依据校正后的数值模型分析了水源地运营后地下水漏斗的范围及水位降深,并对水源地停采后水位恢复状况进行了模拟预报。结果表明:通过模型计算可知,研究区水源地地下水含水层总补给量为62230 m^(3)/d,总排泄量为63400 m^(3)/d,均衡差为-1170 m^(3)/d,多年地下水动态呈负均衡状态;通过对研究区水源地开采2 a、5 a、10 a后承压水状态进行预测,地下水水位分别平均下降6 m、8 m、9 m,形成中心漏斗区,面积分别为54.56 km^(2)、65.04 km^(2)、65.80 km^(2),开采初期降落漏斗急剧扩张,然后速度逐渐放缓;研究区水源地承压含水层开采对周围流场产生了一定的影响,但这种影响主要在开采期较为明显,停抽1 a后漏斗区逐渐恢复,为了水源地的可持续利用及保护,建议严格控制开采量,加强地下水的监测与管理。预测结果可以为水源地保护提供技术支撑。

Clarifying the migration conditions of groundwater is the key basis for the protection of urban groundwater sources.In order to serve the sustainable development of the groundwater source in Shenyang,the authors constructed the hydrogeological conceptual model and groundwater numerical model according to the hydrogeological conditions of the study area.The Visual MODFLOW software was used to solve the model,and the model parameters were identified and verified based on the water level data of observation well.The range of groundwater funnel and the depth of water level drop after water source operation were analyzed according to the corrected numerical model,and the water level recovery after the stop-mining of water source was simulated and predicted.The results showed that the total recharge of groundwater aquifer in the study area was 62230 m^(3)/d,and the total discharge was 63400 m^(3)/d,with equilibrium difference of-1170 m^(3)/d.And groundwater dynamic was in a negative equilibrium state for many years.Through the prediction of the confined aquifer situation after 2 a,5 a and 10 a of water source exploitation,the water level decreased by an average of 6 m,8 m and 9 m respectively,and the area of the central funnel area was 54.56 km^(2),65.04 km^(2)and 65.80 km^(2)respectively.The funnel expanded rapidly in the early stage of mining,and then the speed gradually slowed down.The exploitation of confined aquifer in the water source had a certain impact on the surrounding flow field,but this impact was mainly obvious during the mining period,and the funnel area gradually recovered after one year of stop-pumping.It is suggested that the exploitation amount should be strictly controlled and the monitoring and management of groundwater should be strengthened for the sustainable utilization and protection of water source.The prediction results could provide some technical support for water source protection.