Beijing – October 18, 2026 -- The Huaneng Zangmu Hydropower Station on the Yarlung Zangbo River spent about 360 million yuan ($53.27 million) on a fishway, and the channel has helped about 570,000 fish pass the dam since the plant began operating in 2015.
The station is about 400 meters long and more than 100 meters high. It covers nearly 26 percent of electricity demand in Xizang Autonomous Region and ended the region's reliance on diesel for large-scale power supply.
Ecological spending extends beyond the fishway
Station head Sun Chao said a fast-flowing fish stock enhancement and release station cost 48 million yuan ($7.10 million) to build. Annual fry-breeding costs are nearly 7 million yuan ($1.04 million). The release project has run for 12 years and has put 1.97 million fish into the river.
Seven fish species use the fishway. Two of them, the black-spotted catfish and the Lhasa schizothoracin, are nationally second-class protected animals.
Slow cold-water species forced a gentler design
Design engineer Zhang Lianming said native fish are only semi-migratory. After a dam is built, they may adapt to their new surroundings and stop returning to their birthplace, which fragments habitat and limits genetic exchange between populations.
The design team built a scale-model fishway and tested flow velocities on fish captured from the river. After six years of experiments, it set an inlet flow velocity of 0.92 to 1.2 meters per second as the "comfort zone" for upstream migration.
The open channel has a 2 percent gradient. A rest pool is placed at every 10 meters of rise, with water speed held between 0.9 and 1.2 meters per second. A water-supply branch pipe and a flow-regulating valve at the inlet create the flow that attracts fish.
Team members visited fishway projects in the US and Canada. They found that overseas rivers hold mostly stronger carnivorous migratory fish, so fishways there use a larger lifting angle and can be built over shorter distances. Yarlung Zangbo fish are mostly cold-water species with slow growth cycles and weaker swimming ability, so the fishway needs a smaller lifting angle.
Project challenges the 40-meter convention for fish passes
When completed, the fishway was China's highest-altitude and largest fish-passage ecological protection project, Zhang said. It broke the long-standing convention that fish passes would not be considered for dams over 40 meters high. He expects it to guide fishway construction at future high-altitude hydropower stations.
The team compiled its study of fish ecology and behavior in the river into a monograph. The project won first prize in the 2023 Science and Technology Award in Xizang.
Smart monitoring system logs each migrating fish
A smart monitoring system in the fishway observation room works like an "electronic toll station," collecting information on fish as they pass. Yang Xiaocheng, director of the station's safety and environmental protection department, said the 570,000 upstream passages are backed by data.