不同降雨条件下非点源污染氮负荷入河系数研究

以黑河流域为研究区,利用1998年河道实测径流量、泥沙负荷和非点源污染调查资料,对所建的非点源污染模型进行了参数率定.在此基础上,分析了非点源污染负荷的坡面-入河过程,提出了非点源污染负荷的"流域损失系数-入河系数"的概念;利用研究区的资料,对不同降水条件下农田、城镇、草地、灌木及森林等土地利用类型的各亚流域氮的入河系数进行了研究,对比分析了2种计算方法(SWAT模型方法和输出系数法)所得到的氮的入河系数.结果表明,2种方法所计算的氮的入河系数均较为合理,其计算结果的Pearson相关系数为0.94722(p＜0.05).此外,研究还表明,不同的降水条件和土地利用类型下氮的入河系数存在差异.对于吸附态氮,入河系数的大小排列依次为农田＞城镇＞草地＞灌木＞森林;对于溶解态氮,其入河系数的大小排列次序为农田＞草地＞灌木＞森林＞城镇.

The study of the rate loss of nitrogenous non-point source pollution loads in different precipitation levels

A SWAT model was calibrated using data from runoff, sediment and nitrogen pollution in 1998 in the Heihe river basin. The conception of rate loss in the watershed (RL) for non-point source pollution loads was presented, and the RLs of farmland, town, grass, bush and forest were calculated under different precipitation levels. The comparative study of the RLs of N pollution which was calculated by two methods (the SWAT model and the export coefficient method) was also shown; the correlation numbers were up to 0.9 (the significance level is 0.005). In the end, it was demonstrated that the different adsorptive N RLs for different land uses in descending order were that farmland, town, grass, bush and forest. The descending order of dissolved N RLs were shown as farmland, grass, bush, forest and town.