雅鲁藏布江仲巴至林芝段水环境容量分析

摘要

雅鲁藏布江作为西藏自治区第一大河,其流域内聚集了自治区主要人口和经济.随着西藏自治区经济社会的快速发展,雅鲁藏布江水质污染逐渐严重.进行雅鲁藏布江流域水质和水环境容量评价是对科学合理利用西藏水资源的重要保障,本文根据雅鲁藏布江仲巴至林芝段的CODCr、氨氮、总磷等三种污染物浓度实测数据,使用单因子评价法对研究区沿程水质进行了评价.在此基础上,采用段首控制和断面控制下的一维稳态水质模型分段计算了研究区的理想水环境容量、污染物排放量和剩余水环境容量.结果显示研究区内水体质量整体状况良好,流域内3种污染物均剩余较大的水环境容量,但临近上游2个水功能区内普遍存在总磷超标问题,临近下游的2个水功能区少数计算单元存在较严重的CODCr和总磷排放超标问题,急需削减污染物排放以保障流域内水环境的健康.%The Yarlung Tsangpo River, the longest river in Tibet, houses most of the population and economy in Tibet Autonomous province. Under the rapid development of economy and society in Tibet, the pollution in the Yarlung Tsangpo River basin has rapidly increased. Evaluating water quality and water environmental capacity is needed for water resource management in Tibet. This study used a single factor evaluation method to evaluate water quality of the Zhongba-Nyingchi section of the Yarlung Tsangpo River based on measured data of CODCr, NH3-N and TP in the study area. Based on these data, determinations of ideal water environmental capacity, emissions of pollutants and remaining water environmental capacity of the study area were made by a one-dimensional steady water quality model under either section-head control or cross-section control. The data indicate that most of the monitoring sections in the study area experienced good water quality. The three pollutants all had large remaining water environmental capacity generally, but TP exceeded state levels in the two upstream functional areas, and levels above state standards of CODCr and TP were found in several calculation cells of the two downstream functional areas. Therefore, emissions of pollutants need to be reduced to protect the water environment quality of the Yarlung Tsangpo River.