非点源污染导致的水质恶化事件频发，河流污染尤其严重。本文以大宁河为例，从统计模型与机理模型两个角度，探讨了基于日尺度的非点源污染的水环境效应，极具现实意义。主要结论为：基于LOADEST模型构建了氨氮、总氮、总磷的通量方程，估算了日尺度负荷并与SWAT结果对比分析，综合两种模型，探讨了河流水质的变化，结果表明氨氮和总磷浓度均未超过临界值，氨氮在1月中下旬、4月初及10月中旬浓度较高，总磷在年内中间月份及11月上中旬浓度高；非点源输出的三种污染物均为枯水期负荷量低且较为稳定，平水期和丰水期负荷量较高且变化幅度较大；非点源氮素污染物与河道污染物的日负荷周期变化总体呈正相关关系，磷素污染物的非点源污染与河流污染周期没有明显的相关关系。控制河段不同水文期的水环境容量变化很大，丰水期环境容量超过了平水期和枯水期容量之和。两种污染物均没有超过环境容量，并且剩余环境容量大。

Non-point source (NPS) pollution occurring frequently, especially in watersheds and rivers. On daily scale, the study investigated the effects of NPS pollution on water environment in Daninghe Watershed from statistical and mechanism models. The following conclusions were obtained. Based on LOADEST, this paper constructed the regression equation of Ammonia Nitrogen, TN and TP. Loads on daily scale were evaluated and compared with results of SWAT. Both of Ammonia nitrogen concentration and TP concentration were less than the critical value. Ammonia nitrogen concentration was rather high in mid to late January, early April and mid-October, while TP concentration was relatively high midyear and early to mid-November. The load of all pollutants in the dry season were lower and more stable than those in the abundant water time and the normal season. The result showed positive correlation between nitrogen pollutants from NPS and those in river, overall. As for phosphorus pollutants, there was no obvious correlation between NPS pollution and river pollution. The water environmental capacity of the controlled reach in the abundant water time was more than the sum of that in the dry season and normal season. Moreover, loads of both types of pollutants were much less than environmental capacity.