| 摘要: |
| 长江下游感潮河段水文条件复杂，但是有关其对滨岸湿地水热盐的影响及季节性差异的认识较为匮乏。本文以长江南京段绿水湾湿地为研究对象，监测了湿地水文变化及信号特征，构建了湿地水热运移与氮迁移转化模型，揭示了潮汐过程对湿地水热储量和氮去除量的影响及其季节性差异。研究结果表明：湿地水位水温变化包含径流和潮汐两个信号特征，春夏季径流较强，而秋冬季潮汐波动幅度较大。春夏季河流水位水温升高，水土界面溶解氧水平降低，径流驱动下的湿地氮去除量约为秋冬季的3~5倍。然而，秋冬季潮汐波动幅度约为春夏季的2倍，显著增强了湿地的氮去除量，在径流驱动基础上提升脱氮效率约为63%、31%，约为春夏季的2.5~5倍。研究结果可为长江下游滨岸带生态环境保护提供理论依据。 |
| 关键词: 感潮河流 湿地 水文过程 脱氮 数值模拟 |
| DOI： |
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| 基金项目:国家自然科学基金青年项目(42207240); 江苏省自然科学基金青年项目(BK20200158); 江苏省博士后科研资助计划(2021K143B)；江苏省水利科技项目(2021005) |
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| Numerical study on the influences of complicated hydrological processes on water, heat and salt in the tidal river wetland |
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WEI Lanlin1, LIU Dongsheng1, Wu Jie2, LV Haobo3, ZHANG Wenting4,5,5,6
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1.Nanjing Hydraulic Research Institute;2.Yangtze River Management Division of Nanjing;3.Hohai University;4.School of River &5.amp;6.Ocean Engineering, Chongqing Jiaotong University
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| Abstract: |
| The hydrological condition of the tidal section of the lower Yangtze River is rather complicated, but there is a lack of understanding of its influence on dynamics of the wetland water, head and salt. In this paper, we took the Lvshuiwan wetland in the Nanjing section of the Yangtze River as the research object, monitored the wetland hydrological changes and their signal characteristics, constructed a model of hydrothermal transport and nitrogen migration and transformation for the wetland, and revealed the influence of tidal processes on the hydrothermal storage and nitrogen removal of the wetland and its seasonal differences. The results showed that the changes of water level and temperature in the wetland include two signal characteristics: runoff and tide, with strong runoff in spring and summer, and greater tide fluctuation in autumn and winter. The river water level and temperature rise during wet seasons, with the level of dissolved oxygen at the water-soil interface decreasing, resulting in the runoff-driven nitrogen removal of the wetland 3-5 times that in autumn and winter. However, the amplitudes of tidal fluctuations in autumn and winter are about twice that in spring and summer, which significantly enhances the nitrogen removal of the wetland, and improves the nitrogen removal efficiency by about 63% and 31% on the basis of that driven by runoff, making it about 2.5-5 times that in spring and summer. The research results provide a theoretical basis for the ecological environmental protection of the tidal river wetland in the lower reaches of the Yangtze River. |
| Key words: tidal river wetland hydrologic process denitrification numerical simulation |
