Causes of continuous and short-term hypoxia in rivers entering the sea: a case of Minjiang River in Fujian Province

IF 2.7 4区环境科学与生态学 Q2 Environmental Science

Hydrology Research Pub Date : 2022-12-09 DOI:10.2166/nh.2022.095

Peng Zhang, Bin Wang, Yishu Wang, Y. Pang, Chengchun Shi, Rongrong Xie

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引用次数: 1

Abstract

In the last 10 years, the Minjiang River, which is the longest river in the Fujian Province in Southeast China, has been facing a downward trend of dissolved oxygen (DO) and a frequent occurrence of hypoxia. In this study, the development of the continuous and short-term presence of low DO was investigated by using the water age concept and average DO consumption concept based on a three-dimensional Environmental Fluid Dynamics Code in the Minjiang River. The results revealed that the spatial distribution of DO was affected by temperature, runoff, pollution emission, tidal advection, and hypoxic water discharge from the reservoir bottom. The continuous low DO in the water of the North Channel occurred frequently when the enough pollutants were aerobically decomposed faster than the rate of oxygen reaeration during the high temperature and low river discharge period. In addition, the water age and reaeration time decreased with a rapid increase in the water flow from the Shuikou dam when the reservoir capacity was released via drainage. The results of this study provide scientific insights on the mechanism involved in the occurrence of hypoxia and suggest countermeasures for addressing hypoxic problems in estuaries.

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入海河流持续短期缺氧的成因——以福建省闽江为例

闽江是中国东南部福建省最长的河流，近10年来，其溶解氧呈下降趋势，缺氧现象频发。在本研究中，基于三维环境流体动力学代码，利用水年龄概念和平均DO消耗概念，研究了低DO在岷江中持续和短期存在的发展。结果表明，DO的空间分布受温度、径流量、污染排放、潮汐平流和库底缺氧排水的影响。在高温低流量时期，当足够多的污染物以快于氧气复氧速率的速度进行有氧分解时，北航道水体中经常出现持续的低DO。此外，当通过排水释放水库容量时，水口大坝的水流量迅速增加，水龄和复氧时间也随之减少。这项研究的结果为缺氧发生的机制提供了科学的见解，并为解决河口缺氧问题提出了对策。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Hydrology Research Environmental Science-Water Science and Technology

CiteScore

5.30

自引率

7.40%

发文量

审稿时长

17 weeks

期刊介绍： Hydrology Research provides international coverage on all aspects of hydrology in its widest sense, and welcomes the submission of papers from across the subject. While emphasis is placed on studies of the hydrological cycle, the Journal also covers the physics and chemistry of water. Hydrology Research is intended to be a link between basic hydrological research and the practical application of scientific results within the broad field of water management.