流域生态补偿断面污染通量核算方法分析

Estimation of the Flow Rates and Pollution Fluxes for the Sections of Ecological Compensation

针对生态补偿断面监测方法的通量计算有效性问题,基于自动站逐日监测流量和污染物浓度,确定不同流量水平下的标准污染物通量,比较了生态补偿断面月单次浓度抽检方法所确定的污染物通量与标准通量的差异;分析了流域降雨所形成的面源污染通量,利用多年平均流量、月降雨量计算生态补偿断面通量,在此基础上提出改进方法。结果表明:传统方法 NH_3和I_(Mn)核算通量误差较大,对于大流量地区适应性差。所提出的修正方法有效地计算了降雨所形成的非直排入河面源污染通量,NH_3非汛期和汛期平均误差分别为14.16%和16.24%,I_(Mn)非汛期和汛期平均误差分别为10.24%和14.65%。所提出的改进方法有效地解决了单次抽检方法下的污染通量准确估算问题,为生态补偿金额核算提供了理论依据。

The objective of this study was to estimate monthly flow rate and pollution fluxes at the sections of ecological compensation, i.e., the sections located at the junction between the administrative districts, with limited sampling data of water quantity. Two methods were proposed using multi-year average flow rate, monthly rainfall amount and monitored water quantities as input information. The measured fluxes of NH3 and permanganate index at the ecological compensation sections were used to evaluate the performance of the methods. The results showed that the traditional pollution fluxes error is big, es-pecially for large flow region. The agricultural non-point source（NPS） pollutions increased non-linearly with rainfall. Taking the NPS pollution loads caused by the rainfall into consideration, the relative error between the estimated and measured pollu-tion fluxes decreased to 14.16% and 16.24% for the NH3 during the dry and wet seasons, and 10.24% and 14.65% for the permanganate index during the dry and wet seasons, respectively at the sections. The proposed method would provide a useful tool for the estimation of pollution fluxes at the ecological compensation sections.