水动力条件对三峡库区次级支流优势藻种生长的影响

The Influence of Hydrodynamic Conditions on the Dominant Edge Growth of the Secondary Tributary at Three Gorges Reservoir

摘要: 本研究以嘉陵江支流清水溪为研究对象，取清水溪磁器口段原水进行流速、紊流实验。结果表明，当Chla达到峰值时(14天)硅藻为显著优势藻种，其次为蓝藻、绿藻。当水流速度为0.00~0.12 m/s、紊流耗散率为0.00~0.62 m²/s³× 10−4时对水体中藻类的增长有促进作用，Chla峰值分别为0.124 mg/l、0.158 mg/l，随着流速、紊流耗散率的继续增加藻类生长呈下降趋势，且流速、紊流耗散率越大抑制越明显。当以单一硅藻为研究对象时均得到相似的结果。因此，库区次级支流水动力条件的改变是引起库区次级支流水华爆发的原因。

Abstract: In this study, Qingshui Brook, one of the tributaries of the Jialing River was taken as case study. The ve-locity experiment and turbulent experiment were both demonstrated by using the raw water from the Qingshui Brook in the Ciqikou section. The results show that the diatom is the dominant algae when the Chla reached the peak (14 days), followed by blue algae, green algae. Algae’s growth could be promoted while the flow rate is 0.00 - 0.12 m/s and the turbulence dissipation rate is 0.00 - 0.62 m²/s³× 10−4. At that time, the peaks of the Chla are 0.124 mg/l, 0.158 mg/l. When the flow velocity and the turbulence dissipation rate continue to increase, the growth of the algae is declined. The greater the flow velocity and the turbulence dissipation rates, the more obvious the inhibiting effects. The study shows the similar results when a single diatom is used. It is concluded that the change of hydrodynamic conditions of the secondary tributary at Three Gorges Reservoir is the cause of the local algae bloom.