| 白洋淀不同水体氢氧同位素特征及其指示意义 |
| 摘要点击 1950 全文点击 722 投稿时间：2021-08-19 修订日期：2021-09-01 |
| 查看HTML全文
查看全文 查看/发表评论 下载PDF阅读器 |
| 中文关键词 氢氧同位素 蒸发 水动力 地表水和地下水作用 白洋淀 |
| 英文关键词 hydrogen and oxygen isotopes evaporation hydrodynamics lake-groundwater interactions Baiyangdian Lake |
|
| 中文摘要 |
| 为深入认识白洋淀湿地水文循环过程，于2020年开展大气降雨、河水、湖水和地下水样品采集和测试，揭示了不同水体氢氧稳定同位素特征及其对蒸发、水动力条件、地表水和地下水交互作用的指示意义.结果表明，白洋淀不同水体氢氧同位素特征差异较大，δD和δ18O均值存在如下关系：6月湖水>10月湖水>上层地下水>河水>中层地下水>下层地下水.蒸发作用导致了湖水同位素相对富集，6月和10月蒸发造成的水量损失分别为18.8%~42.3%和2.7%~30.3%.湖水同位素的空间分布受到水动力条件影响，总体上河流入淀口和补水口同位素贫化，远离入河口的淀区同位素富集，航道等水动力条件好的区域同位素分布较为均匀.湖水渗漏对地下水的贡献率为0~91.7%，水平向上空间变异较大，垂向上影响深度约为20 m.渗漏强度和地下水埋深、离湖距离呈负相关，和地下水水力梯度相关性不明显.研究结果可为白洋淀水资源保护和生态保护修复提供基础依据. |
| 英文摘要 |
| In order to better understand the water cycle processes in Baiyangdian Lake, samples for precipitation, river water, lake water, and groundwater were collected in 2020 via the analysis of oxygen and hydrogen isotopes and the total dissolved solids. A combined approach including correlation analysis, end-member modeling, and evaporation modeling was used to identify hydrogen and oxygen isotopic characteristics of different water types and their indicative significance to evaporation, hydrodynamics, and lake-groundwater interactions. The results showed that the compositions of hydrogen and oxygen isotopes in surface water and groundwater differed from each other. The average values of δD and δ18O were the highest in samples from lake water in June, secondary for lake water in October, and the lightest in groundwater. The slope of the lake water line was lower than that of the local meteoric water line, which could be attributed to a greater evaporative enrichment in lake water. The water loss ratio was estimated to be 18.8%-42.3% in June and 2.7%-30.3% in October by applying an evaporation model using deuterium excess. Lake water isotopes exhibited highly spatial heterogeneity, which indicated that Baiyangdian Lake was a poor-mixed lake controlled by the complex hydrodynamic conditions. The values of δD and δ18O were lighter around the estuary area and higher in the district far from the estuary. Although the main water isotopes in areas such as channels had a short residence time, the spatial differences in lake water isotopes were not remarkable, which suggested that the well-mixed conditions of the lake water contributed to reducing the heterogeneity of the lake water isotopic compositions on a spatial scale. The contribution ratios of lake leakage to groundwater were 0-91.7% and varied spatially. It had a negative relationship with the buried depth of groundwater and the distance to the lakeshore. No obvious relationship was found between lake leakage magnitude and groundwater level gradient. This study could provide a theoretical basis and technical support for the sustainable development of water resources and ecological environment protection in Baiyangdian Lake. |
|
|
|
