No evidence connects Three Gorges to droughts - People's Daily Online May 27, 2011
The middle and lower reaches of the Yangtze River are suffering from the worst drought in 50 years, causing water shortages in provinces such as Hubei, Hunan, Jiangxi and Anhui. What is the chief culprit behind the current drought? The public has targeted the Three Gorges reservoir, also known as the "water of quenching thirst," located in the upper reaches of the Yangtze River. Reporters interviewed several departments and experts regarding this statement.
No evidence supports theory that Three Gorges caused droughts
The theory that the Three Gorges caused the drought originated on the Internet. They believe the Three Gorges Project is the chief culprit causing the rare droughts in the middle and lower reaches of the Yangtze River. "The lake between the gorges intercepts the water that should flow to the lower reaches. That is why the climate is affected," a netizen from Beijing said.
This is not the first time that the public has questioned the Three Gorges Project because of the extreme climate. Abnormal weather has frequently hit China in recent years, such as the drought in southwestern China, the extreme heat in Chongqing as well as heavy rain in Dianshan Lake and the Yangcheng Lake Basin. In all these cases, the Three Gorges is often regarded as the main culprit.
In regards to the theory that the Three Gorges caused droughts, some well-known experts and scholars in fields such as meteorology, geology and water conservancy said that currently there is no evidence to support this statement.
Weather experts call drought cyclical weather phenomenon
Liu Min, director of the Wuhan Regional Climate Center under the Hubei Meteorological Administration, which is responsible for the long-term monitoring of the impact on climate conditions from the Three Gorges Project, said that based on the current means and observational data, there is no evidence that supports theory that the Three Gorges Project is the main cause for the drought in the middle and lower reaches of the Yangtze River.
"The current drought is a cyclical weather phenomenon. It is mainly caused by atmospheric circulation. The monitoring data shows that the influence of the Three Gorges on the regional temperature and humidity is very weak both before and after its construction," Liu said.
According to sources, the "Yangtze River Three Gorges Project Environmental Impact Report" has provided a scientific analysis of the climate issue after the construction of the Three Gorges reservoir, and the basic conclusion is that the scope of the affected area of the Three Gorges reservoir on the temperature, humidity, wind and fog of neighboring regions is generally no more than 10 kilometers.
"Due to the La Nina phenomenon, the atmospheric circulation has been in an abnormal state since last year, and the subtropical high pressure system over the western Pacific has been weaker than average. It prevented warm, humid air currents from reaching the middle and lower reaches of the Yangtze River," Liu explained. La Nina has caused cold air to move southwards and kept warm, moist air out of southern China, leading to low rainfall in most areas along the middle and lower sections of the Yangtze River since last November.
Drought would have been even worse without the dam
"We should not blame the Three Gorges Dam for every extreme weather event. In fact, the drought would have been even worse in the middle and lower reaches of the Yangtze River without the dam," said Zheng Shouren, one of the chief designers of the dam, an academician of the Chinese Academy of Engineering and chief engineer at the Yangtze River Water Resources Committee, on May 24.
Zheng said that the dam was designed to store water toward the end of the flood season and to provide water to the middle and lower reaches in the dry season. "Since January this year, massive amounts of water have been released from the Three Gorges reservoir faster than its inflow speed. After the downstream areas were hit by the severe drought, water discharges were increased to between 8,000 cubic meters and 10,000 cubic meters per second, at least 2,000 cubic meters per second faster than the inflow speed," Zheng said.
According to the water level statistics from the China Three Gorges Corporation's cascade dispatching center, the water level of the Three Gorges reservoir has dropped from 175 meters in January to 152.7 meters on May 24. "It indicates that some 173 million cubic meters of water has been discharged to the middle and lower reaches of the Yangtze River," said Zhao Yunfa, deputy chief engineer at the dispatching center.
At the request of the State Flood Control and Drought Relief Headquarters, the Three Gorges reservoir has increased the amount of water discharge on May 20 and now releases more than 300 million cubic meters of water per day to support the drought relief in the lower and middle reaches of the Yangtze River. Currently, the water level monitored by each hydrometric station in Yangtze River has considerably picked up.
To support the drought relief, the Three Gorges reservoir will continue to discharge additional water until June 10, when the flood season of the Yangtze River will come.
Bianhe Township of Jianli County in Jingzhou is a small township on the middle reaches of the Yangtze River and has built ditches to draw water from the Yangtze River for irrigation. The drought relief situation has considerably improved thanks to the increased amount of water discharge by the Three Gorges reservoir. Pan Kejian, deputy head of the township government, has high expectations for the drought relief role of the Three Gorges Project.
Pan believes that the advantages of the Three Gorges project outweigh its disadvantages. He said, "The flood control situation in Jingzhou has improved since the Three Gorges reservoir was built, particularly after a heavy flood in 2010.
In response to public doubts, Cao Guangjing, president of the China Three Gorges Corporation and responsible for the operation and management of the Three Gorges project, said on May 24 that the project should be evaluated from a historical perspective. The China Three Gorges Corporation has always been open-minded to suggestions, opinions and criticism from various sides and has taken measures to minimize the ecological impact of the Three Gorges project since it began storing water.
Cao said, "The evaluation on the Three Gorges project should not only be objective and comprehensive but also see the whole picture. The resettlement of the population at the upper reaches of the Three Gorges reservoir aims to control floods that are dozens of times more threatening in the lower reaches of the Yangtze River and maintain the long-term stability of the entire country. Following the construction of the project, some related changes were inevitable as the price that China must pay. Nothing in the world is perfect, and the key is to weigh both advantages and disadvantages. It is necessary to take these issues seriously, but it is wrong to assert that the Three Gorges project is a mistake."
By People's Daily Online
