关键词: 水华, 叶绿素a, 国家水质标准, 汉江中下游, 南水北调中线工程

Abstract: Algae blooms often occur in relatively static water bodies such as lakes. However, algae blooms have also appeared in flowing water bodies such as the Hanjiang River in China in recent years. The algae bloom in the middle and lower reaches of the Hanjiang River in 2018 has a large influence range and a long duration, which is typical and representative. In order to prevent and control water blooms to ensure water supply safety, based on the monitoring data and countermeasures of the typical water blooms, the paper put forward a series of thoughts and suggestions by analysis and investigation. The results showed that: ①The high density, long duration and wide range of diatom blooms in 2018 had posed a threat to the safety of water supply, however, the emergency water dispatching measures had a good effect on restraining the blooms;②It was suggested that chlorophyll-a index should be included in the national water quality standards, and standard limits should be set by considering conditions in different regions. It was also suggested to strengthen the prevention and control of pollution along the river basin, increase and improve the equipment of algae removal in waterworks, and further optimize the water dispatching scheme of cascade reservoirs in the middle and lower reaches of the Hanjiang River. The relevant measures and suggestions have some reference significance for the prevention and control of river algae blooms.

Key words: algae bloom, Chlorophyll a, Middle Route of South to North Water Diversion Project, national water quality standard, middle and lower reaches of Hanjiang River