| 三峡水库不同支流库湾蓄水期溶解氧分层特性及差异性 |
| 摘要点击 1906 全文点击 657 投稿时间：2021-09-27 修订日期：2021-11-20 |
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| 中文关键词 溶解氧(DO) 厌氧 热分层 水动力 三峡水库 |
| 英文关键词 dissolved oxygen(DO) anaerobic thermal stratification hydrodynamics Three Gorges Reservoir |
| 作者 | 单位 | E-mail | | 纪道斌 | 三峡大学水利与环境学院, 宜昌 443002
三峡水库生态系统湖北省野外科学观测研究站, 宜昌 443002 | dbji01101@163.com | | 方娇 | 三峡大学水利与环境学院, 宜昌 443002 | | | 龙良红 | 三峡大学水利与环境学院, 宜昌 443002
三峡水库生态系统湖北省野外科学观测研究站, 宜昌 443002 | 893310859@qq.com | | 杨正健 | 三峡大学水利与环境学院, 宜昌 443002 | | | 赵星星 | 三峡大学水利与环境学院, 宜昌 443002 | | | 杨霞 | 中国三峡集团流域枢纽运行管理中心, 宜昌 443133 | | | 郭亚丽 | 上海勘测设计研究院有限公司, 上海 200335
中国长江三峡集团有限公司长江生态环境工程研究中心, 上海 200335 | |
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| 中文摘要 |
| 以三峡水库典型支流库湾小江和香溪河为例，通过2020年蓄水期不同阶段的野外监测，对比分析了两条支流库湾的水动力过程、热分层、溶解氧时空差异及其对蓄水过程的响应.结果表明：①蓄水初期，小江库湾表层受大气复氧和浮游植物影响溶解氧较高（7.00~13.00 mg ·L-1，其氧跃层出现在水深3~5 m处，5 m以下水域出现大面积缺氧（DO<2.00 mg ·L-1），甚至无氧现象.香溪河库湾溶解氧在垂向上大致可以分为3层：表层富氧水体（8.00~12.00 mg ·L-1）、中层水体（6.00~8.00 mg ·L-1）和底层低氧水体（4.00~6.00 mg ·L-1）.②稳定的热分层为底层厌氧的形成提供了稳定的物理环境，而小江上游来流以及消落带植被分解增加了水体有机质的含量，可能是造成小江水体耗氧量增大、形成厌氧的内因；而香溪河因为长期存在的顺坡异重流补给，底层水体缺氧的风险较低.③持续的跟踪监测发现水库蓄水对支流库湾溶解氧起到了显著的补给作用，促使小江库湾厌氧现象在短期内得到有效改善.针对三峡水库，通过水库调度来改善支流库湾的缺氧和厌氧等水生态问题是可行的.结果进一步加深了对三峡水库不同支流库湾溶解氧分层特征及其差异的理解，从而为水库生态调度提供理论及技术支撑. |
| 英文摘要 |
| Taking the Xiaojiang and Xiangxi Rivers, two typical tributaries of the Three Gorges Reservoir, as examples, this study analyzed and compared the hydrodynamic, thermal stratification, and temporal and spatial differences in dissolved oxygen (DO) and their responses to the water storage process in the two tributaries through field monitoring at different stages of the 2020 impoundment period. The results showed that:① at the initial stage of water storage, the DO in the surface layer of the Xiaojiang River was higher (7.00-13.00 mg·L-1) due to atmospheric reoxygenation and phytoplankton photosynthesis, and the oxycline appeared in the water depth of 3-5 m. A large area of anoxia (DO<2.00 mg·L-1) or even an anaerobic sublayer occurred in the water below 5 m. The DO in the Xiangxi River could be divided into three layers vertically:oxygen-rich surface water (8.00-12.00 mg·L-1), middle water (6.00-8.00 mg·L-1), and low-oxygen bottom water (4.00-6.00 mg·L-1). ② Thermal stratification provided a stable physical environment, whereas the upstream inflow and vegetation decomposition in the water-level fluctuation zone increased the content of organic matter, which likely increased the oxygen consumption which was conducive to the formation of an anaerobic bottom layer. In the Xiangxi River, the risk of hypoxia in the bottom water body was low because of the oxygen replenishment from the long-term downslope-bottom density current.③ Continuous monitoring also showed that the storage of the reservoir played a significant role in the replenishment of DO in tributaries, which effectively and rapidly improved the anaerobic phenomenon in the Xiaojiang River. In the Three Gorges Reservoir, it is feasible to ameliorate the water ecological problems such as anoxia and anaerobic conditions in the tributaries via reservoir operation. This study aids understanding of the characteristics and differences of DO stratification in different tributaries of the Three Gorges Reservoir, which can provide theoretical and technical support for reservoir ecological operation. |
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