| 三峡支流大宁河库湾水质分布变化原因及其生态效应 |
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| 引用本文： | 韩超南,秦延文,马迎群,赵艳民,刘志超,杨晨晨,张乐.三峡支流大宁河库湾水质分布变化原因及其生态效应[J].环境科学研究,2020,33(4):893-900. |
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| 作者姓名： | 韩超南 秦延文 马迎群 赵艳民 刘志超 杨晨晨 张乐 |
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| 作者单位： | 1.中国环境科学研究院水环境研究所水环境管理研究室, 北京 100012 |
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| 基金项目： | 国家重点研发计划项目（No.2017YFC0404702）；国家水体污染控制与治理科技重大专项（No.2017ZX07107001） |
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| 摘 要： | 为探讨三峡支流大宁河库湾水体水质分布变化的原因及其产生的生态效应，从大宁河库湾污染源、三峡干支流水体交换等视角，建立三峡干流与大宁河库湾交换水量的计算公式，监测大宁河库湾表层水样水质的逐月变化情况，重点分析不同调度期三峡干支流水体交换变化驱动下大宁河库湾水质时空分布的响应变化.结果表明:①三峡干流回水倒灌、大宁河上游来流是大宁河库湾水量、TN、TP等的主要来源，干流表层水体EC（电导率）、ρ（TP）和ρ（TN）均高于大宁河上游来流.②蓄水期至高水位期，在干流回水倒灌作用和库湾水量滞留作用的影响下，库湾表层水体EC、ρ（TP）和ρ（TN）高值分布向上延伸至距离入江口0~20 km及以上的库湾水域.泄水期至低水位期，干支流交换水量为负值，表示库湾流出水量高于干流回水倒灌水量.这两个时期库湾表层水体EC、ρ（TP）和ρ（TN）高值分布首先集中于距离入江口0~5 km的库湾水域，随后向库湾中游方向延伸，可能因泄水后期、低水位期仍有少量干流回水从中表层方向倒灌以及库湾中游藻密度高引起.③5-9月距离入江口0~20 km的库湾中游、下游水域藻密度明显高于其他时期其他水域，与水温适宜、非氮非磷限制的营养结构TN/TP（摩尔比）为30~40]促进藻类生长繁殖有关.研究显示，不同调度期干支流水体交换是驱动大宁河库湾水质分布变化的重要因素，进而库湾水体氮、磷营养结构的时空变化一定程度上影响着浮游藻类生长分布.
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| 关 键 词： | 三峡水库 大宁河 水质分布 干流回水 生态效应 |
| 收稿时间： | 2019/3/1 0:00:00 |
| 修稿时间： | 2019/8/14 0:00:00 |
Cause of Variation in Water Quality Distribution and Its Ecological Effects in the Daning Bay of the Three Gorges Reservoir |
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| HAN Chaonan,QIN Yanwen,MA Yingqun,ZHAO Yanmin,LIU Zhichao,YANG Chenchen,ZHANG Le.Cause of Variation in Water Quality Distribution and Its Ecological Effects in the Daning Bay of the Three Gorges Reservoir[J].Research of Environmental Sciences,2020,33(4):893-900. |
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| Authors: | HAN Chaonan QIN Yanwen MA Yingqun ZHAO Yanmin LIU Zhichao YANG Chenchen ZHANG Le |
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| Affiliation: | 1.Water Environmental Management Laboratory, Institute of Water Environment Research, Chinese Research Academy of Environmental Sciences, Beijing 100012, China2.School of Civil Engineering, Nanjing Forestry University, Nanjing 210037, China |
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| Abstract: | The purpose of this research was to discuss the variation in water quality distribution and its ecological effects in the Daning Bay, a tributary bay of the Three Gorges Reservoir (TGR). For the perspective of pollution sources and water body exchange between the TGR mainstream and tributary, a formula for calculating the water exchange capacity between the TGR mainstream and the Daning Bay was established. Surface water samples in the Daning Bay were collected to analyze monthly variations of water quality parameters in response to the water exchange changes during the different scheduling periods. The results showed that:(1) The inflows of the TGR backwater and the upstream inflows of the Daning River were two main sources of water, total nitrogen (TN) and total phosphorus (TP) of the Daning Bay. The electrical conductivity (EC), TN and TP concentrations in the surface water in the TGR mainstream were higher than that in the upstream of the Daning River. (2) Due to backwater intrusion from the TGR mainstream in the impounding period and water retention in the Daning Bay in the high water level period, water areas with high EC, TN and TP concentrations in surface water were distributed in the middle and lower reaches of the Daning Bay, which were 0-20 km above the entrance of the Daning Bay to the TGR mainstream. During the sluicing period and the low water level period, the water exchange capacities between the TGR mainstream and the Daning Bay were negative, which indicated that the outflows of the Daning Bay were higher than the inflows of the TGR backwater. From the sluicing period to the low water level period, water areas with high EC, TN and TP concentrations in surface water were firstly concentrated in 0-5 km above the entrance of the Daning Bay to the TGR mainstream, and then upward extended to the middle reach of the Daning Bay. These may be caused by small amount of backwater intrusion in the direction of upper and middle water layer and the concentrated distribution of algal biomass in the middle reach of the Daning Bay during the later stage of the sluicing period and the low water level period. (3) In suitable water temperature and optimum water trophic structure without phosphorus limitation and nitrogen limitation, the TN/TP ratio in water was in between 30-40, algal density in the middle and lower reaches of the Daning Bay from May to September was significantly higher than that in the other periods and water areas. This study indicated that the water body exchange between the TGR mainstream and tributary was an important factor driving the variation of water quality distribution in the Daning Bay, and the temporal and spatial changes of nutrient structure (TN/TP) influenced algal biomass distribution in the Daning Bay to some extent. |
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| Keywords: | Three Gorges Reservoir Daning River water quality distribution mainstream backwater ecological effect |
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