基于GMS的某高寒场区地下水环境影响研究

A GMS-based study on the environmental impact of groundwater in an alpine field

地下水数值模拟是进行地下水环境影响定量评价的重要手段,运用GMS三维数值模型手段,可高效评价地下水污染物的迁移规律。以西藏日喀则市某危废处理项目为研究对象,合理进行概化,建立地下水渗流模型和溶质运移数学模型,模拟场区污染物运移情况,对研究区污染泄露后特征污染因子的扩散进行预测,预测该危废处理项目运行后对地下水环境的影响。结果表明:研究区污染物迁移受地下水水流方向影响,方向为由近西向近东方向,污染物迁移距离较小,对场区下游地下水造成影响较小。COD污染物在水平方向上主要向地下水下游扩散,非正常状况下,洗车区废水收集池泄漏20年后COD的污染晕沿地下水流方向上的最远运移距离为500 m,最大影响范围62590 m^(2),最大超标范围25960 m^(2);污染物泄漏浓度随时间先增加后逐渐减小。模拟结果为场区地下水环境影响评价和污染应对提供科学依据。

Numerical groundwater modelling is an important tool for quantitative groundwater environmental impact assessment.Using GMS 3D numerical modelling tools,the migration patterns of groundwater contaminants can be efficiently evaluated.Taking a hazardous waste treatment project in Rikaze,Tibet as the research object,a reasonable generalization was made to establish a groundwater seepage model and a solute transport mathematical model to simulate the transport of pollutants in the site area,to predict the dispersion of characteristic pollutants after pollution leakage in the study area,and to predict the impact of this hazardous waste treatment project on the groundwater environment after its operation.The results show that the transport of pollutants in the study area is influenced by the direction of groundwater flow,which is from the near west to the Near East,and the pollutant transport distance is small,causing less impact on the groundwater downstream of the site.COD pollutants in the horizontal direction mainly spread downstream to the groundwater,under abnormal conditions,the farthest transport distance of COD′s pollution halo along the groundwater flow direction after 20 years of leakage from the wastewater collection pond in the car wash area is 500 m,with a maximum impact area of 62590 m^(2) and a maximum exceedance area of 25960 m^(2);The concentration of spilled pollutants increases and then decreases over time.The simulation results provide a scientific basis for groundwater environmental impact assessment and pollution response at the site.