三峡库区重点支流水华现状、成因及防控对策

自2003年6月三峡水库蓄水以来，库区支流富营养化和水华问题备受关注。对库区12条重点支流2010—2020年的水质、水华监测数据进行了统计分析，结果表明：12条重点支流均发生过典型水华，近几年水华发生次数减少；水华主要发生在3—9月，以蓝藻和硅藻水华为主。暴发水华的根本原因是水体营养盐充足。支流监测数据表明，水体均处于中营养状态及以上。适宜的温度、光照和缓慢的水动力条件则是暴发水华的重要原因。目前，开展营养盐削减是控制三峡库区重点支流库湾水华的根本途径；通过物理方法、化学方法和生物操控方法消除水华的应用尚且较少；而通过水库生态调度抑制水华为可行方法。

Current situation,causes and control measures of water bloom in the key tributaries of the Three Gorges Reservoir

Since the impoundment of the Three Gorges Reservoir in June 2003, the problems of eutrophication and water blooms of the tributaries have attracted much attention. The monitoring data of water quality and bloom in 12 key tributaries of the reservoir area from 2010 to 2020 were analyzed statistically. The results showed that typical water blooms occurred in 12 key tributaries, and the frequency of water blooms decreased in recent years. Water blooms mainly occured from March to September, and the dominant species were cyanobacteria and diatoms. The root cause of the outbreak of water bloom was the sufficient nutrients in water. The monitoring data of tributaries showed that the tributaries were all in medium nutrient state or above.. Appropriate temperature, light and slow hydrodynamic conditions are important causes of the outbreak of water blooms. At present, nutrients reduction is the fundamental solution to reduce water blooms in the tributaries of the Three Gorges Reservoir area. Physical, chemical and biological methods are rarely used to reduce water blooms. It is feasible to control water bloom through reservoir ecological operation.