Provinces along China’s lower Yangtze River have recently suffered through a record heat wave and the worst drought in decades. With the drought affecting 12.2 million people and damaging 840,000 hectares of crops, public debates over the long-controversial Three Gorges Dam have resurfaced on Sina Weibo, China’s twitter.
“All the past prophecies have come true,” a popular Weibo user with 414,000 followers @_-冰翼-_ , who claims to be a vice general manager at a software tech company in Shenyang, wrote in a viral post shared over 36,000 times：
“The peoples’ anger is boiling over… Poyang (鄱阳) and Dongting (洞庭) Lakes are drying up. Extremely abnormal weather is happening downstream of the Yangtze River, including major drought unseen in the last 50 years, floods, and more frequent earthquakes. The only benefit of the big dam is to generate electricity, but all the profits have gone to monopoly and aristocracy, while innocent common people have experienced more disasters. If people don’t break it down, God will.曾经的预言已全部兑现：鄱阳湖和洞庭湖干涸，长江中下游气候极端反常，西南地区50年不遇大旱、洪涝、地震频发。好处只剩下一个：发电！但发电的收入全都被权贵家族垄断，而比这个发电效益巨大到无法比拟的灾难却由无辜老百姓承担！人不拆，天来拆！不要再对子孙后代造孽”
Poyang and Dongting Lakes are the second and third largest freshwater lakes in China and an essential water resource for over 60 million people.
Weibo user @张洲, a young director with 111,086 followers, holds a similar opinion.
“Tomorrow, in Zhejiang, Anhui and Jiangxi, the temperature will exceed 40°C (104°F). The climate along the Yangtze River has become increasingly abnormal. When some said the main reason is the Three Gorges Dam, experts all came out to deny the rumor. Today, I overheard a hydrology expert chatting. He was half drunk and said: ‘If you block a river into stagnant water, it’s absolutely normal that the temperature will rise. You always feel cooler around a flowing river than a stagnant pond. Even fools know this.’明天，浙皖赣等局地最高温将超40℃。近年来我国长江流域气候异常，有人说三峡是主因，专家们纷纷跳出来辟谣，今听一个水利专家聊天，他在半醉时举了一个例子：把小河截住围住成死水，温度升高再正常不过，如一个死水池塘，边上通常酷热升腾，而流动的小河边上则清凉爽身，傻瓜都明白这个理。”
@巴豆虫, a retired engineer, wrote:
“The dam formed a large area of artificial lakes, destroying the original hydrological balance and interfering with existing meteorological laws. Also, it destroyed a large amount of vegetation that can absorb carbon dioxide. The rotten vegetation in the bottom of the lake can produce large amounts of methane, whose effects are 21 times that of carbon dioxide.形成大面积人造湖，破坏了原有水汽平衡，干扰了原有气象规律。此外毁掉大片吸收二氧化碳的植被还不说，湖底沉积腐殖物将不断地产生大量甲烷，其作用是二氧化碳的21倍.”
While many netizens supported these critiques, others argued that climate change and global warming were the culprit for drought, not the Three Gorges Dam. User @海-豚-王 wrote, “A bunch of idiots. Look at foreign countries. They are all suffering from high temperatures. You guys only know how to spread stupid rumors. Shame!说这些话的人一群蠢蛋！眼睛看远点，看看国门外，哪里不是高温？你们这些尽在这里传播低级谣言，丢人哦!” Some also appraised the dam as a valuable tool to control flooding. @名字太血腥 wrote, “Low IQ bloggers! If there’s no Three Gorges Dam, your grandpa would have long been washed away by the flood, and you would never have existed in this world.博主，低智商！没有三峡，你爷爷早就被洪水冲跑了，哪来了你这个乖孙子哟！” @白云蓝蓝天, a user currently in the United States, wrote, “Liberal intellectuals only know how to curse the government. He recommended we abandon hydropower; then should we use coal again or nuclear power or just recommend the public stop using electricity? You have to give advice. Everybody knows how to curse.建议我们废弃水电，是用煤炭烧的火电还是核电呢？或者建议老百姓不用电？总要给个建议吧，骂一通谁都会.”
The chatter versus the reality
The Chinese social Web is a contested space, populated by, among others, liberal intellectuals (“gongzhi”) and conservative, pro-Communist “five-centers,” and many are not above spreading rumors to achieve their advocacy goals. In this case, however, the critics are probably right. Research shows that negative environmental impacts of the Three Gorges Dam really do exist, even if they are not as severe as some online complaints.
China’s Three Gorges Dam is the world’s largest hydroelectric dam based on generating capacity. It is 1.3 miles wide, over 600 feet in height, and has a reservoir behind the dam that stretches 405 square miles to help control flooding on the Yangtze River basin. But in controlling large flooding, the Three Gorges Dam often worsens small and moderate flooding. Here’s how: the Yangtze River’s annual river flow is about 25 times bigger than the Three Gorges Reservoir’s capacity, and 80% of its river flow is concentrated in the wet season. If the dam does not make the needed discharges during the early wet season when rain and flooding is not very strong, the reservoir will fill, rendering it unable to control large floods when the stronger rains come. This means the dam must clear its reservoir when rain is not as strong; but this makes small floods larger.
Making matters more complicated, when the Three Gorges Dam discharges water, sediments in the water settle in the dam instead of flowing downstream. The absence of silt means that downstream river banks are more vulnerable to erosion and flooding.
Whether the Three Gorges project affects airflow and climate is another issue that needs further study. One hypothesis is that the large evaporation of the reservoir behind the dam has formed a new low-pressure area near the Sichuan basin. This new low pressure area causes the winter monsoon to move further south, and causes the summer monsoon to come earlier. The result: southern China has colder winters, eastern China has longer and hotter summers, and major monsoon rainfall shifts from south of the Yangtze, leaving the river downstream suffering from drought, while southern China suffers from floods.
The connection between the dam and earthquakes is more obvious. Records show that the sheer weight of water collected behind the Three Gorges Dam affects seismic activity. Christian Klose, a researcher from Columbia University, has estimated the extra water weight at about 320 million tons, which he argues “amplifies the strain on the earth’s crust in a way that alters the stresses below.”
While we can’t conclude that the Three Gorges Dam is the cause of the 2008 historic 8.3 magnitude on the Richter scale Wenchuan (汶川) Earthquake, a 2010 seismologic study by the China Earthquake Administration indicates that the dam “significantly increased seismic activity” along the reservoir. The study says that “seismic monitors around the reservoir and Hubei Province registered 3,429 earthquakes between June, 2003 (when inundation of the reservoir began) and December 31, 2009,” which represents a “30-fold increase in frequency over the pre-dam period.” Fan Xiao, a chief engineer at the Sichuan Geology and Mineral Bureau, warns that “strong earthquakes could occur in the future as the reservoir fills because the microfractures, caused by the large number of microearthquakes, could make the area dangerously prone to a strong earthquake.”
The negative environmental impacts of this great dam are hard to deny, particularly given findings connecting the dam to erosion, sedimentation, landslides, and earthquakes. Government authorities have started to admit to some negative impacts like water pollution, seismic hazards, loss of biodiversity and the limits of the area’s ecological capacity. China’s State Council also passed Three Gorges Dam Follow-Up Plan and Yangtze River Downstream Water Pollution Control Plan in May of 2011.
In sum, online commenters are right to worry about the Three Gorges Dam. But their complaints are not precise or scientific; while they may encourage further transparency, they also muddy the truth at the same time.