Liu Xin-Yuan, Song Lin-Xu, Ji Dao-Bin, Liu De-Fu, Cui Yu-Jie, Huang Jia-Wei, Zhao Chong, Tang Yong-Chun, Ping Ming-Ming
College of Hydraulic and Environmental Engineering, Three Gorges University, Yichang 443002, China.
Hubei Key Laboratory of Ecological Restoration of River-lakes and Algal Utilization, Hubei University of Technology, Wuhan 430068, China.
Huan Jing Ke Xue. 2018 Feb 8;39(2):774-782. doi: 10.13227/j.hjkx.201708203.
There were three rainfall events with different intensity in the Xiangxi Bay (XXB) from May 24 to June 2 in 2016. The factors such as hydrodynamics, water temperature, optical properties, and chlorophyll a concentrations during the rainfall events were analyzed. During the May 27 moderate rain period, the upstream flow of the reservoir bay increased by 1.9 times and the average mixing layer depth in the whole reservoir increased 8.2 m, compared to those before the rainfall event. During the June 1 light rain period, the average mixing layer depth in the whole reservoir increased 1.6 m and the average chlorophyll concentration reduced 2.02 μg·L, compared with those before the rainfall event. During the June 2 heavy rain period, the upstream flow of the reservoir bay increased by 4 times, the average mixing layer depth in the whole reservoir increased 7.9 m and the average chlorophyll concentration reduced 14.64 μg·L, compared with those before the rainfall event. The algae moved from the upstream to the downstream with water that reduced the concentration of algae in the XXB. The water temperature stratification weakened during the rain event and the average mixing layer depth in the whole reservoir increased, destroying the algal growth environment. After the rainfall, under suitable light and temperature conditions for 2-3 d, the water temperature stratification of the reservoir was recovered and rapid growth and reproduction of algae occurred. As a result, the chlorophyll concentrations in the reservoir increased. Rainfall has a periodic inhibitory effect on the outbreak of algal blooms; however, it cannot fundamentally solve the problem of tribal bay blooms.
2016年5月24日至6月2日，湘西湾（XXB）出现了三场强度不同的降雨事件。对降雨事件期间的水动力、水温、光学特性和叶绿素a浓度等因素进行了分析。在5月27日的中雨期间，与降雨事件前相比，水库湾上游流量增加了1.9倍，整个水库的平均混合层深度增加了8.2米。在6月1日的小雨期间，与降雨事件前相比，整个水库的平均混合层深度增加了1.6米，平均叶绿素浓度降低了2.02μg·L。在6月2日的大雨期间，与降雨事件前相比，水库湾上游流量增加了4倍，整个水库的平均混合层深度增加了7.9米，平均叶绿素浓度降低了14.64μg·L。藻类随着水流从上游向下游移动，降低了湘西湾藻类的浓度。降雨事件期间水温分层减弱，整个水库的平均混合层深度增加，破坏了藻类的生长环境。降雨后，在适宜的光照和温度条件下2 - 3天，水库的水温分层恢复，藻类迅速生长繁殖。结果，水库中的叶绿素浓度增加。降雨对藻华爆发有周期性抑制作用；然而，它不能从根本上解决库区藻华问题。
