source:Peoples Daily - environmental protection channel agency editor in charge:Yu Lu, Li Fang

People's daily, Beijing, May 23 (Reporter Yu Lu) recently, cyanobacteria gathered in a large area in some waters of Taihu Lake. It is understood that with the increasing temperature and the influence of high temperature and less rain, the possibility of large-scale outbreak of cyanobacteria will be further increased. This year, Taihu Lake is facing a more severe test of safety in summer. In this regard, Jiangsu Provincial Water Resources Department, Wuxi City and Suzhou city put forward the demand of water diversion from the Yangtze River to Taihu Lake Basin Administration Bureau of the Ministry of water resources. In order to ensure the safety of Taihu Lake in summer and the water supply safety of water sources, the Taihu Lake Basin Authority started water resources regulation of diverting water from the Yangtze River to Taihu Lake on May 21.

According to the relevant staff of the Taihu Lake Basin Authority, on May 11, satellite remote sensing interpreted that the area of cyanobacteria bloom in Taihu Lake was 822.6 square kilometers, which was the largest bloom area so far this year. According to the monitoring results of the hydrological and water resources monitoring center of Taihu Lake Basin, the average density of cyanobacteria in Taihu Lake from January to April was 25.5 million cells / L, slightly higher than that of 25.34 million cells / L in the same period of last year. The main reason is that the warm and humid climate in the last winter and this spring is remarkable. The winter temperature in Taihu Lake Basin is 2 ℃ higher than that of many years, which is conducive to the recovery and growth of cyanobacteria, resulting in the early outbreak of cyanobacteria and wide range of this year.

From May 20 to 21, Wu Wenqing, director of the Bureau of Taihu Lake, led a team to Wuxi City, Jiangsu Province, to investigate the water conservancy prevention and control of cyanobacteria in Taihu Lake, observed the occurrence of cyanobacteria blooms on site, and studied with relevant local responsible comrades the measures to further improve the prevention and control of cyanobacteria and ensure the safety of Taihu Lake in summer.

In view of the large area of cyanobacteria accumulating in Gonghu Bay and Meiliang lake, the water supply safety of Taihu Lake water source area may be affected. In the afternoon of May 21, Taihu Bureau organized a meeting in time to further analyze the weather, water and rain situation and the water quality of cyanobacteria in the basin, and made arrangements for the security of water supply in the basin on the basis of full consideration of local demand. The meeting held that, due to the influence of high temperature and little rain in the early stage, the water level of Taihu Lake is low (2.98 m on May 21, 0.12 m lower than the average water level for many years, and 0.02 M lower than the water level limited by water diversion). At the same time, the late weather forecast rainfall is still relatively small. The meeting decided to start water resources dispatching from Yangtze River to Taihu River from 15:00 on the 21st, and adjust Changshu water control project of Wangyu River to jointly dispatch water by gate and pump The daily water diversion from the river is 12 million cubic meters. In view of the fact that the Taihu Lake Basin is in the flood season at present, in order to prevent the possible rapid change of drought and flood, the Taihu bureau also requires the relevant departments to effectively control the flood control risk in the flood season, and the Zhangqiao water level should be controlled at no more than 3.70 meters. In the next step, the Wangting water control project will be opened in time to divert water into the lake according to the relevant regulation scheme of Taihu Basin and the water quality of Wangyu River, so as to ensure the safety of water supply for the important water sources of Taihu Lake.

At the same time, the Taihu Lake Bureau also deployed to strengthen the monitoring and early warning of cyanobacteria in Taihu Lake, and made every effort to do a good job in the prevention and control of cyanobacteria in Taihu Lake. At present, the Taihu Lake Bureau has established a dynamic monitoring system for water resources of Taihu Lake body, drinking water source areas and rivers entering and leaving the lake, covering hydrological meteorological and water ecological elements such as water level, flow rate, water quality, cyanobacteria density, etc. A total of 23 cyanobacteria information video collection points, 33 water quality and cyanobacteria density monitoring points were set up in Taihu Lake. The occurrence of cyanobacteria in Taihu Lake was monitored by using FY satellite remote sensing images and MODIS satellite remote sensing images. The occurrence and change of cyanobacteria in Taihu Lake was comprehensively sensed by means of automatic monitoring, artificial patrol and satellite remote sensing analysis, and the occurrence and development trend of cyanobacteria bloom in Taihu Lake was predicted intelligently. Since the launch of diverting water from the Yangtze River to Taihu Lake, the Taihu Bureau has deployed to increase the frequency of water quality monitoring from once every two days to once a day, paying close attention to the cyanobacteria in the water source areas, so as to grasp the water quality information of the water sources in time.

At present, the Taihu Lake Basin is still in flood season. In the next stage, Taihu Bureau will pay close attention to the situation of cyanobacteria and the water quality of Taihu Lake and other major water bodies. Meanwhile, it will pay close attention to the changes of weather situation, strengthen communication and coordination with provinces and cities in the basin, strengthen consultation and analysis, forecast, project scheduling and inspection, and do a good job in the prevention and control of cyanobacteria in Taihu Lake, and ensure the water supply and water ecological safety of the basin All.