| 引用本文: | 李楷文,丁梦瑶,范宏翔,吴华武,雷蕊宇,付丛生,李静,辛未,张赐成.基于氢氧稳定同位素的鄱阳湖流域“五河”新水比例及其滞留时间量化研究.湖泊科学,2025,37(1):266-278. DOI:10.18307/2025.0142 |
| Li Kaiwen,Ding Mengyao,Fan Hongxiang,Wu Huawu,Lei Ruiyu,Fu Congsheng,Li Jing,Xin Wei,Zhang Cicheng.Quantifying the young water fraction and residence time of five inflow rivers for Lake Poyang using stable hydrogen and oxygen isotopes. J. Lake Sci.2025,37(1):266-278. DOI:10.18307/2025.0142 |
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| 摘要: |
| 流域河流新水比例和滞留时间是表征径流过程以及污染物、营养物质运输的重要参数。确定水的来源及其在流域内的滞留时间，对于理解流域水文过程和功能至关重要。为了定量解析鄱阳湖流域河流的新水比例和滞留时间，本文通过对鄱阳湖流域降水及河水（赣江、修河、信江、抚河、饶河，以下简称“五河”）稳定同位素（δ18O和δD）的高频率监测与分析，利用正弦拟合方法分析了降水和河水δ18O和δD值的变化。结果表明：（1）“五河”河水及降水氢氧同位素表现出相似的季节变化特征，雨季（5—7月）较为贫化，旱季（12月—次年2月）较为富集，河水同位素变化与局地降水同位素、地下水同位素密切相关，说明流域内不同水体之间存在良好的水文连通性；（2）“五河”流域内小于3个月的新水占比范围为3%~42%，流域内滞留时间范围为123.83~2495.0 d，其中赣江平均滞留时间最长、新水比例最低，乐安河和昌江的新水比例最高、平均滞留时间最短；（3）流域面积和单位面积上干流长度是“五河”流域新水比例的主要控制因素，坡度与新水比例存在负相关关系，但其负相关性被单位面积上干流长度与新水比例的正相关性所掩盖；（4）修河、赣江流域较其他流域显著受到蒸发分馏的影响；（5）鄱阳湖湖水同位素值明显高于河水，且在湖口站点湖水同位素值较都昌站点偏低，这表明湖口站湖水受长江来水和蒸发分馏的影响。该研究结果有助于对鄱阳湖流域水文联系和水文过程进行解析，可为流域污染物的输移模拟及其机制阐释等提供科学参考。 |
| 关键词: 鄱阳湖流域 新水比例 平均滞留时间 氢氧同位素 水文过程 |
| DOI：10.18307/2025.0142 |
| 分类号: |
| 基金项目:国家自然科学基金项目（42071145，42201105，42301034）；江西省自然科学基金项目（20232BAB213053）；湖南省自然科学基金项目（2022JJ40274）联合资助 |
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| Quantifying the young water fraction and residence time of five inflow rivers for Lake Poyang using stable hydrogen and oxygen isotopes |
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Li Kaiwen1，2，3，Ding Mengyao3，4，Fan Hongxiang3，Wu Huawu3，Lei Ruiyu3，4，Fu Congsheng3，Li Jing5，Xin Wei6，Zhang Cicheng1，2
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1.Hunan Key Laboratory of Geospatial Big Data Mining and Application, Hunan Normal University, Changsha 410081 , P.R.China ；2.School of Geographical Sciences, Hunan Normal University, Changsha 410081 , P.R.China ；3.Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 211135 , P.R.China ；4.University of Chinese Academy of Sciences, Beijing 100049 , P.R.China ；5.School of Geographic Information and Tourism, Chuzhou University, Chuzhou 239000 , P.R.China ；6.State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 , P.R.China
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| Abstract: |
| River young water fraction and residence time are critical parameters for describing streamflow processes, as well as the transport of pollutants and nutrients within a watershed. Determining the sources of water and its residence time within the watershed is critical for us to understand watershed behavior and functionality. To quantify the river young water fraction and residence time for the Lake Poyang Basin, this study conducted high-frequency monitoring of stable isotopes (δ18O and δD) in precipitation and river water for five major inflow rivers of the basin, i.e., the Gan River, Xiu River, Xin River, Fu River, and Rao River (hereinafter refered to as “Five Rivers”). The study analyzed the variations in δ18O and δD values for precipitation and river water using a sine fitting method. The study achieved the following findings. (1) The deuterium and oxygen isotopes in the “Five Rivers” water and precipitation exhibited similar characteristics, i.e., low isotopic values during the rainy season (May to July) and high values during the dry season (December to February in the following year). There was a high correlation between river water isotopic variations and precipitation isotopes as well as groundwater isotopes, indicating good hydrological connectivity among different water bodies in the watershed. (2) The young water fraction in the “Five Rivers” catchments, with an age less than 2 months had a range from 3% to 42%. Its mean residence time varied from 123.83 days to 2495.0 days. Among the inflow rivers, the Gan River had the longest mean residence time and the lowest young water fraction, while the Le'an River and the Chang River exhibited the highest young water fraction and the shortest mean residence time. (3) Catchment area and the main stream length per unit area were identified as the primary driving factors for the young water fraction in the “Five Rivers” catchments. Slope was negatively correlated with the young water fraction. However, the negative correlation was overshadowed by the positive correlation between the main stream length per unit area and the young water fraction. (4) Compared with other catchments, the Xiu River and Gan River catchments were more significantly influenced by evaporative fractionation. (5) Lake Poyang water had significantly higher isotopic values than river water. Within Lake Poyang, the Hukou station had lower isotopic values than the Duchang station. This result indicated a combined influence of Yangtze River and evaporative fractionation on Lake Poyang water. The study improved our understanding of hydrological connections and processes within the Lake Poyang Basin, and thus provided a scientific reference for modelling mass transport and learning the underlying mechanisms. |
| Key words: Lake Poyang Basin young water fraction mean residence time hydrogen and oxygen isotopes hydrological processes |
