大宁河流域非点源污染不确定性分析

以大宁河流域为研究区,利用2000-2005年巫溪水文站实测的径流量、泥沙负荷对非点源污染模型进行参数率定和验证.采用蒙特卡罗方法分析径流量、泥沙负荷、吸附态氮、溶解态氮和总磷等非点源污染的不确定性影响因素.结果表明,如果忽略模型参数的不确定性会导致流域非点源污染负荷的低估,模型输入与输出的关系是非线性的.非点源污染的不确定性具有周期性变化规律,夏秋丰水期的不确定性大,春冬枯水期的不确定性小.并且径流的不确定性较小,泥沙和营养物的不确定性较大,不确定性来源与径流过程参数和土壤属性参数有很大关系.

UNCERTAINTY ANALYSIS OF NON-POINT SOURCE POLLUTION IN DANING RIVER

The origin and the pollution load of non-point sources are uncertain, which makes controlling and managing non-point sources difficult. Analyzing the uncertain effect factor of non-point source provides the basis for controlling measure. Using Daning river watershed as the study area, runoff and soil load data for the period of 2000-2004 are applied for parameter calibration and validation. Monte Carlo method is used to analyze the uncertain effect factor of runoff, soil load, organic N, NO3-N and TP. Results indicate that if the uncertain component of model parameters are neglected, it would cause the non-point source pollution load to be underestimated and the relationship of model input and output to be non-linear. Uncertainty of non-point source pollution follows the law of period change, uncertainty is bigger in the summer and smaller in the winter. The uncertainty of runoff is less, the uncertainty of soil load organic N, NO3-N and TP are bigger, and the uncertainty source is mainly affected by parameters related to the flow generation process and soil property.