| 引用本文: | 苏毅捷,代俊峰,莫磊鑫,等.漓江上游灌区小流域不同尺度氮磷污染排放负荷研究[J].灌溉排水学报,2018,37(5):92-98. |
| SU Yijie,DAI Junfeng,MO Leixin,et al.漓江上游灌区小流域不同尺度氮磷污染排放负荷研究[J].灌溉排水学报,2018,37(5):92-98. |
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| 摘要: |
| 【目的】开展野外原位监测试验，揭示漓江上游灌区小流域不同尺度氮磷污染排放规律，为面源污染控制和治理提供参考。【方法】利用ArcGIS软件和SWAT模型，基于DEM数据对漓江流域青狮潭灌区金龟河试区进行子流域划分，考虑水系和渠系分布，从试区上游至下游选择具有水力联系且从小到大逐级嵌套的5个尺度，于2016年5—12月对试区各尺度出水口进行了监测，研究了氮磷质量浓度和排放负荷变化。【结果】从空间尺度1（面积335.41 hm2）增大到尺度5（面积2 798.15 hm2），质量浓度总氮沿程呈上升趋势，由尺度1出水口的0.95 mg/L增加到了到尺度5出水口的2.42 mg/L；氨氮与总磷沿程呈现波动性变化，在尺度3（面积1 135.36 hm2）与尺度5中呈现急剧增加的特点。灌溉季节的氮磷排放负荷大于非灌溉季节，灌溉季节总氮、氨氮、总磷排放负荷由尺度1到尺度5分别下降了54.60%、41.46%、55.77%。非灌溉季节总氮排放负荷随尺度增大而增大，从试区尺度1单位面积总排放负荷0.67 kg/hm2增加到尺度5单位面积总排放负荷2.76 kg/hm2，氨氮与总磷排放负荷则表现为波动性变化。在灌溉季节，沟渠、塘堰对氮磷的去除以及排水的重复利用，减少了污染物的排放；而在非灌溉季节，沟渠、塘堰面积由原来的55.91 hm2减少为13.92 hm2，减少了75.10%，导致去除效果下降，且随尺度增大养殖场污染物排放量大量增加。【结论】漓江流域水稻灌区氮磷排放控制和污染物消减，应考虑不同时间和空间尺度下氮磷污染物运移的特点。 |
| 关键词: 氮磷排放； 灌区； 尺度； 时空变化； 小流域 |
| DOI：10.13522/j.cnki.ggps.2017.0419 |
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| Discharge of Nitrogen and Phosphorus at Different Scales over a Small Watershed within an Irrigation District in Upstream of the Li River |
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SU Yijie, DAI Junfeng, MO Leixin, ZHANG Lihua, ZENG Honghu
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Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541004, China; 2. Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004, China
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| Abstract: |
| 【Objective】 This paper is to present the results of an experimental investigation into the discharge of nitrogen and phosphorus at different scales from a small watershed within an irrigation district in the upper stream of the Li River, with a view to provide baseline data for controlling and mediating their pollution. 【Method】 We first divided Jingui Experimental Area in Qingshitan Irrigation District on the upstream of the Lijiang River into a number of sub-catchments based on DEM and ArcGIS and SWAT model. From the terrain of the river and canals, we considered five scales which were hydraulically connected. In-situ experiment was then conducted from May to December in 2016 to measure the concentration of nitrogen and phosphorus as well as their discharge rate at the outlet of the experimental area. 【Result】 The concentration of total nitrogen was scale dependent, increasing from 0.95 mg/L to 2.42 mg/L when the spatial scale increased from 335.41 hm2 to 2 798.15 hm2. In contrast, the concentration of ammonia and total phosphorus fluctuated as the scale increased, increasing fast only in the third scale, 1 135.36 hm2, and the fifth scale. The discharge of nitrogen and phosphorus was higher in irrigation season than in non-irrigation season, with the discharge of total nitrogen, ammonia and total phosphorus decreased by 54.60%, 41.64% and 55.77% respectively when the scale increased from 335.41 hm2 to 2 798.15 hm2. In non-irrigation season, the discharge of total nitrogen increased from 0.67 kg/hm2 to 2.76 kg/hm2, while the discharge of ammonia and total phosphorus fluctuated, as the scale increased. 【Conclusion】 In irrigation season, the leaching of nitrogen and phosphorus into drainage ditches and ponds as well as the reuse of the effluent reduced their discharge. However, in non-irrigation season, the area of ditches and ponds reduced by 75.10% from 55.91 hm2 to 13.92 hm2, resulting in a decrease in removal efficiency and an increase in pollutant discharge. As such, the scale-effect of nitrogen and phosphorus discharge should be taken into account in studying nitrogen and phosphorus emission and pollutant in the Lijiang River Basin. |
| Key words: nitrogen and phosphorus releases; irrigated area; scale; spatiotemporal variations; small watershed |
