南水北调来水后土壤污染物溶出对密云水库水质的影响

Impact of added inundation area soil contaminants release on the water quality in miyun reservoir after water diversion from South-to-North Water Diversion Project

南水北调工程来水入密云水库使得库区水位大幅上升,库区周边大面积土壤将被永久淹没。本文基于密云水库水流条件和入库污染物的迁移扩散规律,构建了适合库区水流水质特征的平面二维水动力与水质模型,结合土壤浸泡溶出试验得出的土壤污染物释放规律,开展了南水北调来水后考虑新增淹没区土壤溶出和不考虑土壤溶出两种情景下的水质模拟,分析了南水北调工程来水后新增淹没区土壤TP、TN和CODMn溶出对库区水质的影响。模拟结果表明,在考虑最不利情景下,新增淹没区土壤释放对密云水库库区水质的影响范围小、程度低、持续时间短,对库区水质的影响非常微弱。

The water level of Miyun Reservoir will increase drastically after the water from the South-toNorth Water Diversion Project flows into the reservoir. Riparian land around the reservoir will be inundated permanently. Based on the water flow conditions and the migration and diffusion of contaminants in Miyun reservoir,this paper takes into consideration the release regularity form soil immersion and dissolution test,and build a two-dimensional model of hydrodynamics and water quality that is suitable for the reservoir.Water quality simulation was carried out under two scenarios:considering soil contaminants release in new inundation area,and not considering soil contaminants release. The effect of soil contaminants(TP、TN and CODMn) release in new inundation area on reservoir water quality was analyzed. The simulation results show that under the most unfavorable situation,the influence of these three soil contaminants release in the new inundation area on water quality in Miyun Reservoir is of small-scale, low-extent and short-duration,and the impact on water quality of whole reservoir is very small.