三峡水库蓄水后小江水环境容量的变化  

Change of Water Environmental Capacity in the Xiaojiang River after Impoundment of the Three Gorges Reservoir

作　　者：王晓青[1,2] 郭劲松[1] 

机构地区：[1]重庆大学城市建设与环境工程学院,重庆400045 [2]长江水利委员会长江上游水文水资源勘测局,重庆400014

出　　处：《环境科学研究》2012年第1期36-42,共7页Research of Environmental Sciences

基　　金：中国科学院西部行动计划项目(KZCX2-XB2-07-02);国家水体污染控制与治理科技重大专项(2009ZX07104-002,2009ZX07104-003)

摘　　要：三峡水库蓄水后的高水位条件下,长江支流小江回水区的水文情势发生了变化,流速减缓,水域污染物本底浓度值因回水涌入而改变,水环境参数与天然状态有很大区别,对小江水域的水环境容量造成很大的影响.根据小江的水功能区划及水功能区水质目标,采用垂线平均的二维水流、水质数学模型,计算蓄水前后CODMn、TN和TP水环境容量的逐月值和年总量.结果表明:受污染物降解系数减小和蓄水后水质目标值减小的影响,与蓄水前的自然状态相比,蓄水后CODMn的水环境容量总量减少约24.15%,TP的水环境容量总量减少约82.72%,TN的水环境容量由蓄水前不受限制变为蓄水后受到限制.水环境容量的减少是三峡水库蓄水后小江水域富营养化现象增多的重要因素之一.The hydrological conditions of the Xiaojiang backwater were greatly changed at the high water level after impoundment of the Three Gorges reservoir.Water velocities were significantly reduced,and the background pollutant concentrations were changed due to inflow from the Yangtze River.Water environment parameters were vastly different compared with those naturally occurring,and the water environmental capacity of the Xiaojiang River was significantly impacted.According to the water functional division and water quality control target,the annual and monthly values of the permanganate index（CODMn）,total nitrogen（TN） and total phosphorus（TP） before and after the impoundment were computed based on depth-averaged 2D hydrodynamic and water quality models.The results showed that after the impoundment of the Three Gorges reservoir,the water environmental capacities of CODMn and TP in the Xiaojiang River were reduced by approximately 24.15% and 82.72%,respectively,and that of TN went from unlimited to limited.The reduction in water environmental capacity is one of the major reasons for water eutrophication in the Xiaojiang River.

关 键 词：小江 三峡水库 水环境容量 

分 类 号：X143[环境科学与工程—环境科学]