采用径流分割法(丰枯径流差值法)、降雨量差值法和径流量差值法,基于2005—2014年各月水文和水质数据,进行漓江流域上游非点源污染负荷量的估算。结果表明,径流分割法的非点源污染负荷计算精度最高,丰枯水期污染物负荷差值和流量差值的拟合方程决定系数在0.88以上;基于径流分割法的污染物总负荷计算值和实测值的决定系数在0.91以上,计算值与实测值的结果接近。与氨氮和高锰酸盐指数相比,不同方法计算的总磷非点源污染比例呈现较强的稳定性。径流分割法的计算结果显示,2005—2014年高锰酸盐指数的非点源比例平均值为0.70,氨氮的非点源比例平均值为0.73,总磷的非点源比例平均值为0.74,说明非点源污染对漓江流域上游水质的贡献率较高。
Based on the hydrological and water quality data during 2005-2014,runoff division method,rainfall deduction method and runoff deduction method were used to evaluate the non-point source pollution respectively in the upstream of Lijiang River.Compared with rainfall deduction method and runoff deduction method,the accuracy of runoff division method is the highest.The relationship between pollution load difference and runoff difference in wet and dry period can be described by a linear equation,with R-2 values greater than 0.88.The calculated values of pollution load using runoff division method were significantly correlated with the measured values,and the R-2 reached 0.91.Compared with NH_3-N and COD_(Mn),the ratio of non-point source pollution to total pollution load of TP calculated by the different methods showed strong stability.The Average value caculated by runoff division method showed that the ratio of non-point source pollution to total pollution load of COD_(Mn),NH_3-N and TP was 0.70,0.73 and 0.74 respectively.It shows that non-point source pollution load highly contributes to the water quality in the upstream of Lijiang River.