| 西湖龙泓涧流域暴雨径流氮磷流失特征 |
| 摘要点击 2839 全文点击 1154 投稿时间：2015-07-27 修订日期：2015-09-08 |
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| 中文关键词 龙泓涧流域 非点源污染 暴雨 径流 营养盐流失 |
| 英文关键词 Longhong ravine basin non-point source pollution rainstorm runoff nutrient loss |
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| 中文摘要 |
| 为掌握西湖入湖溪流龙泓涧流域非点源污染现状,研究了一年内3场暴雨径流过程中营养盐的流失特征. 结果表明,长历时暴雨事件一般会形成多个径流峰值,而其滞后于雨强峰值的时间取决于当次强降雨的分布. 降雨的初期冲刷效应与前期降雨量有关,前期降雨量越少,总磷和氨氮的初期冲刷效应越明显,在退水阶段滞缓的壤中流会使总氮和硝态氮再产生一个浓度峰值. 径流中各形态氮素的平均浓度(EMC)与降雨量、降雨历时、最大雨强和平均雨强均表现为负相关,与前5 d的降雨量表现为正相关,而总磷的EMC值与氮素有相反的变化规律. 径流营养盐迁移通量随降雨量的增大而上升,Pearson分析表明总氮、硝态氮与径流水深(流量)具有较好的相关性. 总磷、总氮、硝态氮和氨氮的平均迁移通量分别为34.10、1195.55、1006.62和52.38 g ·hm-2,硝态氮为主要的氮素迁移类型(占总氮的84%). |
| 英文摘要 |
| In order to understand the non-point source pollution status in Longhong ravine basin of Westlake, the characteristics of nutrient losses in runoff was investigated during three rainstorms in one year. The results showed that long duration rainstorm event generally formed several runoff peaks, and the time of its lag behind the peaks of rain intensity was dependent on the distribution of heavy rainfall. The first flush was related to the antecedent rainfall, and the less rainfall in the earlier period, the more total phosphorus (TP) and ammonia (NH4+-N) in runoff was washed off. During the recession of runoff, more subsurface runoff would result in a concentration peak of total nitrogen (TN) and nitrogen (NO3--N). The event mean concentration (EMC) of runoff nitrogen had a negative correlation with rainfall, rainfall duration, maximum rain intensity and average rain intensity except for antecedent rainfall, whereas the change in TP EMC showed the opposite trend. The transport fluxes of nutrients increased with an elevation in runoffs, and Pearson analysis showed that the transport fluxes of TN and NO3--N had good correlations with runoff depth. The average transport fluxes of TP, TN, NH4+-N and NO3--N were 34.10, 1195.55, 1006.62 and 52.38 g ·hm-2, respectively, and NO3--N was the main nitrogen form and accounted for 84% of TN. |
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