流域基流氮磷流失的非点源污染定量研究

利用数字滤波技术,在结合基流营养物负荷量消退过程和气象因子影响分析的基础上,提出并建立了基流营养物日负荷量分割的递归滤波算法,对浙江嵊州长乐江流域基流氮磷流失进行定量分析。结果表明,基流总氮(TN)日负荷量模拟值的R2为0.86,模拟效率系数NSE为0.72;基流总磷(TP)日负荷量模拟值的R2为0.65,NSE为0.63。用该方法对长乐江流域2003—2012年基流养分流失量的定量分析结果表明,全流域TN和TP年平均基流流失量分别高达1 317.6t(15.25kg/hm2)和51.8t(0.60kg/hm2),占该流域平均TN和TP总径流流失量的61.82%和56.92%。随着降雨量的增加,长乐江流域近年来的基流TN和TP流失量均呈现出极显著的上升趋势,已经成为河流非点源污染不可忽视的重要污染源。

Quantitative Study on Nitrogen and Phosphorus Loss in Baseflow of Typical Agricultural Watershed Based on Non-point Source Pollution Model

Based on the combination of baseflow nutrient load recession analysis and meteorological factors, and digital filtering technology was used, a recursive filter loading separation algorithm (RFLSA) based on the daily load fraction of baseflow nutrient was proposed and established. Quantitative analysis of the total nitrogen (TN) and total phosphorus (TP) loss of baseflow was carried out in the Changle River Basin of Zhejiang, Shengzhou. The results showed that The R2 of baseflow TN daily load simulation was 0.86, and the simulation efficiency coefficient NSE was 0.72, and the above parameters for baseflow TP were 0.65 and 0.63. The mean annual TN and TP loss through baseflow in the studied watershed from 2003 to 2012 were 1 317.6 t (15.25 kg/hm2) and 51.8 t (0.60 kg/hm2), respectively, and accounted for 61.82% and 56.92% of the TN and TP loss in annual total runoff. Along with the increasing of precipitation during 2003 to 2012, the baseflow TN and TP losses showed a significant upward trend, and has become an important pollution source of non-point source pollution of rivers.