漓江流域上游水质分析和污染物定量分割

Water Quality Analysis and Segmentation of the Pollution Loads in Different Spatial Scales of the Upstream of Lijiang River

在科学保护漓江、维持优良生态环境的需求下,漓江流域水质分析和非点源污染定量化十分必要。以2005-2014年青狮潭水库坝首、大面断面和桂林水文站的高锰酸盐指数、氨氮和总磷为对象,分析评价漓江流域上游不同尺度的水质状况,并运用水文估算法、径流分割法和数字滤波法对点源与非点源污染负荷进行分割。结果表明,处于上游的青狮潭水库坝首高锰酸盐指数高于大面断面和桂林水文站,处于下游的桂林水文站断面的氨氮和总磷含量高于青狮潭水库坝首和大面断面。3种方法计算的桂林水文站断面高锰酸盐指数、氨氮和总磷的非点源污染比例平均值分别是0.64、0.74和0.68,非点源污染对漓江的水质影响较大。基于数字滤波法的计算结果显示,漓江流域上游3个空间尺度的氨氮和总磷非点源污染比例的年际波动较大。高锰酸盐指数、氨氮和总磷的非点源污染比例的最大值出现在漓江流域上游3个空间尺度的中游(大面断面)和下游(桂林水文站)。

It is important to analyze the water quality and segment the pollution loads under the requirements of scientific protection of Lijiang River and ecological environment. Water quality of the upstream of Lijiang River was analyzed by using permanganate index （CODMn）, am- monia nitrogen （ NH3-N） and total phosphorus （TP） in the dam foundation of Qingshitan Reservoir, Damian Hydrological Station and Guilin Hydrological Station during 2005-2014. And the segmentation of point source pollution and non-point source pollution was made based on the hydrological estimation method, hydrograph separation method and digital filtering method. The results show that CODMn in the monitoring section of Qingshitan reservoir dam foundation was higher than that in Damian Hydrological Station and Guilin Hydrological Station. NH3-N and TP content in Guilin Hydrological Station were higher than those in Qingshitan Reservoir Dam foundation and Damian Hydrological Sta- tion. Average value of three estimation methods show that the ratio of non-point source pollution to total pollution load of CODMn ,NH3-N and TP was 0.64, 0.74 and 0.68 respectively. The results of digital filtering method indicate that ratio of non-point source pollution to total pollution load of NH3-N and TP fluctuated greatly in three spatial scales in the upstream of Lijiang River. Maximum value for the ratio of non-point source pollution to the total pollution load of CODMn, NH3-N and TP appeared in Damian Hydrological Station and Guilin Hydrological Station.