基于不确定性方法的河流水环境容量计算

为解决中小河流水文水质资料序列长度较短而导致确定性方法计算的水环境容量精度较低,无法科学合理地划定分期限制纳污红线的问题,考虑河流水环境系统参数的不确定性,应用延拓盲数法和蒙特卡洛法计算水环境容量,并结合水功能区目标与污染物排放规模来划定分期限制纳污红线。以丹阳市鹤溪河为实例分析,在现状污染源排放条件下,鹤溪河水环境污染较严重的3～6月共需削减0.06 t氨氮入河量,其余月份氨氮的限制纳污红线为13.67 kg/d。通过实例证明,两种不确定性方法应用在中小河流的水环境容量计算中是可行有效的,在分期限制纳污红线的划定中考虑不确定性方法的计算结果更为科学合理。

Calculation on river water environmental capacity based on uncertainty method

Short sequence of hydrological data of small and medium rivers is unable to delimit pollution load red line scientifically, reasonably by deterministic method in calculating water environmental capacity. Considering the uncertainty of river water environment system parameters, the extended blind number method and Monte Carlo method are used to calculate the water environment capacity, and the staged limiting pollution load red line is delineated by combining the target of water function area and the discharge scale of pollutants. Taking Hexi River in Danyang City as an example, under the present condition of pollution source discharge, the amount of ammonia nitrogen entering the river is required to reduce by 0.06t from March to June, the limiting pollution load red line of ammonia nitrogen was 13.67 kg/d in the rest of the year. The example proves that the two uncertainty methods are feasible and effective in the calculation of water environmental capacity of small and medium rivers. It is considered that the calculation results of uncertainty methods are more scientific and reasonable in the definition of staged limiting pollution load red line.