Reservoir flood regulation affects nutrient transport through altering water and sediment conditions
Reservoir flood regulation affects nutrient transport through altering water and sediment conditions
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水库洪水调节通过改变水和沉积物条件影响养分输送
DOI：
10.1016/j.watres.2023.119728
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发表时间：
2023
期刊：
影响因子：
12.8
通讯作者：
Zhang Wei
中科院分区：
文献类型：
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作者：
Tang Xianqiang;Li Rui;Wang Danyang;Jing Zheng;Zhang Wei
水库建设对营养物动态的影响已经得到了广泛的认识，但在洪水事件尺度上，水库洪水调控对营养物运移的影响却很少得到关注。本文以长江三峡水库为例，于2021年9月三峡水库调洪期间，对水库干流及坝前、坝后水样进行了采集，以确定调洪对营养物质（氮、磷）分布和运输的影响。结果表明，硝态氮（NO3-N）和颗粒磷（PP）是总氮（TN）和总磷（TP）的主要组分，所占比例分别为46.5% ~ 95.6%和57.4% ~ 81.6%。N和P对洪水调节的响应不同：(1)沿河磷浓度因PP随沉积物沉积而显著降低，而N浓度在洪水调节期间几乎没有变化；（ii）坝后段磷浓度显著高于坝前段，氮浓度保持不变。对洪水调节的不同响应导致TN/TP比值从库尾的4-8上升到坝附近的20以上，这可能导致库头区富营养化。该研究揭示了洪水调控对洪水事件中营养物质运移的影响，为水库管理提供了科学依据。
The effect of reservoir construction on nutrient dynamics is well recognized, at flood event-scale influence of reservoir flood regulation on nutrient transport however has received less attention. Taking the Three Gorges Reservoir (TGR) in the Changjiang River as an example, during the TGR's regulation on a flood in Sep., 2021, this study collected water samples along the mainstream of the reservoir as well as pre/post-dam, with the aim to identify the impact of flood regulation on nutrient (nitrogen and phosphorus) distribution and transportation. Results show that nitrate nitrogen (NO3-N) and particulate phosphorus (PP) were the main fraction of the total nitrogen (TN) and total phosphorus (TP) with the proportion of 46.5 %-95.6 % and 57.4 %-81.6 %, respectively. N and P responded different to flood regulation: (i) along the stream P concentration significantly decreased due to PP deposited with sediment while N concentration barely changed during flood regulation; (ii) P concentration was significantly higher at post-dam section than at pre-dam section, while N concentration maintained the same. The diffed response to flood regulation caused TN/TP ratio increased from 4-8 in the reservoir tail to over 20 near the dam, which probably arise eutrophication in the reservoir head area. This study reveals the influence of flood regulation on nutrient transport in flood event and provides scientific basis for reservoir management.