Upstream of the Three Gorges Dam on the Yangtze River in China, 12 immense dams are planned or under construction. The dams, which produce the energy needed to power China’s growing economy, will turn the Yangtze into a stepped cascade of reservoir pools.
But one critically important 250-mile stretch of flowing water will remain. It is a rare fish reserve, a sanctuary for more than 140 species of fish, 70 of which occur nowhere else on Earth.
These fish and their habitat could be at risk, however, if yet another new dam proposed by the city of Chongqing, located just downstream, is built.
Established in 1996 on the stretch of river between the cities of Yibin and Chongqing, the Upper Yangtze Rare and Native Fish Reserve was designed to counter the negative impacts of the dams on the river’s fish.
The fish reserve is home to some of China’s rarest fish species including the Yangtze sturgeon and Chinese paddlefish, which are now critically endangered due to loss of habitat and dams that block breeding migrations.
The reserve is not only important for the fish themselves, but for the people living along the Yangtze, which until very recently supported productive fisheries. Recent years are seeing an alarming decline in fishery resources.
At more than 4,000 miles in length, the Yangtze is the world’s third longest river after the Nile and Amazon. More than 400 million people live in the river valley and depend on the river for electricity, food, drinking water, transport, tourism, and other industries.
The Yangtze is also home to a third of all the fish species in China. About half of those species, approximately 162, are found nowhere else.
Having a free-flowing stretch of river like the Upper Yangtze Rare and Native Fish Reserve is essential for fish that have evolved over thousands of years to the unique conditions found there.
According to Professor David Dudgeon, an aquatic ecologist at the University of Hong Kong, free-flowing segments of river are critical for fish breeding.
“Fish reproduction in the Yangtze and other rivers depends on the maintenance of natural flow patterns because they set the cues for breeding and stimulate breeding migrations,” Dudgeon said. “Dams pose barriers to fish migrations that are associated with breeding—if the fish cannot complete their migrations, they will not breed.”
“Some species of fish have floating eggs that develop as they are carried downstream by the current,” Dudgeon added. “If the length of the flowing segment is reduced by a dam, these eggs will end up accumulating behind the dam wall and will likely not hatch.”
Since 1996, the boundaries of the Yangtze River fish reserve have been changed numerous times to accommodate new dams. At this point, however, there is nowhere else for the reserve to go.
“Considering the booming hydropower development on the tributaries of the Upper Yangtze, this reserve is the last home for these rare and native fish species,” said Qiaoyu Guo, a technical advisor to the Conservancy's Yangtze River Project.
Through the Great Rivers Partnership, Guo and staff from the Conservancy’s China and Global Freshwater programs have been working with public and private partners in China, including the China Three Gorges Project Corporation and the Yangtze Water Resources Commission, for over five years to improve how dams on the Upper Yangtze River are designed and operated.
David Harrison, senior advisor to the Conservancy’s Global Freshwater team, said the new Xiaonanhai dam that the Chongqing municipal government is proposing to build in the fish reserve will produce a small fraction of the hydropower that larger dams like Three Gorges are capable of generating.
“We believe there is a more economical and environmentally-sound alternative to the Xiaonanhai dam,” Harrison commented. “There are other ways for Chongqing to get the power it needs without building a new dam in the last free-flowing stretch of the Upper Yangtze River.”
According to Guo, one possible alternative would involve a partnership between the municipality of Chongqing and the China Three Gorges Project Corporation, which is currently developing several other hydropower projects on the Upper Yangtze that could help meet Chongqing’s energy needs.
Despite wide ranging opposition to Xiaonanhai, the proposed dam is very close to receiving final approval. In the meantime, the Conservancy is continuing to promote alternatives to building this high-impact dam.
“Our heart will ache if this dam is built in the fish reserve,” said Guo, “so we are doing what we can to help find a solution that meets the region’s energy needs and protects this unique freshwater resource for our native fish and the people who depend on them.”