基于MODFLOW-NWT的尾矿库地下水环境影响评价

尾矿库渗滤液中污染物会对区域地下水产生不利影响。根据拟建工程场地水文地质条件和气象资料,建立三维数值预测模型并分析非正常工况下两种典型污染情景对地下水环境的影响,预测结果显示:特征污染物As的质量浓度随时间推移逐渐变大;防渗层破损和无防渗情况下污染晕沿地下水流方向最远运移距离在第100 d、1 000 d、7 884 d时分别为72 m、225 m、262 m和78 m、335 m、391 m。由于下游河流及周边泉点为区内地下水排泄主要途径,污染物经排泄进入下游河流将对环境造成较大影响,故提出相应防范措施。

Environmental Impact Assessment of Groundwater in Tailings Reservoir by Using MODFLOW NWT

The pollutants in the leachate from tailings reservoirs have adverse effects on the regional groundwater. Based on the hydrogeological conditions and meteorological data at the planned engineering worksite, a three dimensional numerical prediction model was established to analyze the influence of two typical pollution scenarios on the groundwater environment under abnormal conditions. The results showed that the mass concentration of the specific pollutant As gradually increased with time. Under damaged impermeable layer or no seepage control conditions, the farthest migration distance of the pollution plume along the groundwater flow direction on 100th day, 1 000th day and 7 884th day were 72 m, 225 m, 262 m and 78 m, 335 m, 391 m respectively. Since downstream river and the surrounding springs were the main drainage ways for groundwater, and discharged pollutants would have huge impacts on the downstream environment, some appropriate preventive measures were put forward.