Ecological beauty adds green to the world's largest clean energy corridor

At the turn of spring and summer, the world's largest clean energy corridor on the main stream of the Yangtze River is breathtakingly beautiful. Flowers, trees, birds, fish, green waters and green mountains are like a painting, showing the beauty of ecology.

"Ecological priority, green development", behind the construction of the "corridor" is the Three Gorges people's unchanging pursuit of protecting the natural ecology.

Water Spirit——

The rushing river is the source of energy for the "corridor" and has been the home of various aquatic groups for thousands of years. These water elves are being carefully cared for and continue to reproduce and live in their familiar home.

In 2019, a field test study was launched at the Wudongde Hydropower Station. With the help of underwater robots, Doppler scanning, echo sounders and other equipment, the scientific research team conducted experimental research on the distribution of fish below the dam and the upstream clustering. This rigorous experiment is to find the most suitable fish collection and transportation system construction plan for the fish that have lived in this basin for generations.

Wudongde stocking and release activityPhotographer: Zhao Jian

"The tailwater fish collecting boxes on the left and right banks are mainly designed for flowing fish such as the round-mouthed copper fish and the long-finned goby. The fixed fish collecting station on the right bank can take into account flowing fish as well as fish that can adapt to different flow velocities, such as the catfish, cobia, and catfish." After years of research, demonstration, and careful design and construction, this fish collection and transportation system introduced by Sun Gan, an engineer from the Environmental Protection Department of Three Gorges Construction Engineering Co., Ltd., which is affiliated to the Three Gorges Group, was created. It will help the fish in the river keep moving forward.

Since the commissioning of the fish collection and transportation system of Wudongde Hydropower Station, a total of more than 63,000 fish have been collected, and major fish species such as round-mouthed copper fish, long-finned goby, long thin loach, and fine-scaled schizothorax have been successfully collected. Monitoring results show that the elves in the water are not stingy with their vigorous vitality and are enjoying the convenience brought by this fish collection and transportation system.

Upstream of the Xiluodu Dam, the water from the Jinsha River flows through the water inlet to the unit, starting a wonderful energy conversion. This important juncture also hides the "water temperature, which is one of the important natural signals for fish spawning." Yu Jiang, deputy director of the Environmental Protection Department of the Three Gorges Construction Engineering Group, introduced.

Monitoring shows that after the reservoir of the high dam and large reservoir power station is filled with water, the water temperature in the reservoir in front of the dam will show stratification. Compared with the natural river section during the same period, the discharge of low-temperature water will lower the downstream water temperature to a certain extent, affecting the signal of fish spawning.

"The upstream reservoir is exposed to more solar radiation and other factors, which makes the surface temperature of the reservoir higher than the bottom layer. As long as as much surface water as possible is transported to the downstream through the water diversion and power generation system, the temperature of the downstream can be raised." Yu Jiang recalled that the Xiluodu Hydropower Station therefore carried out research and preliminary implementation of stratified water extraction, which achieved certain results.

With the construction of Wudongde and Baihetan hydropower stations, stratified water intake has been further studied, applied and optimized. "The elevation of the water inlet floor, the height of the stacked beam gate layer, and the number of stacked beam gate operation and closing equipment have all been optimized through the Wudongde and Baihetan hydraulic model tests."

The right bank water inlet of the Baihetan Hydropower Station, where the stratified water intake facilities are arranged. Photo: Zhao Jian

Spring is back, and everything is coming back to life. Every year at this time of year, Yichang City, Hubei Province, welcomes the release of Chinese sturgeons in the river basin.

Along the "corridor", stocking and release activities continue to be carried out, and more forces are being gathered to join the ranks of ecological and environmental protection.

The Heishui River, a first-level tributary of the Jinsha River on the left bank of Liangshan Prefecture, Sichuan Province, has completed the first phase of the ecological restoration project of the Heishui River fish habitat, an ecological restoration demonstration project of the "Ecological and Environmental Protection Plan for the Yangtze River Economic Belt" participated by the Three Gorges Group. It was also from 2019 that the Three Gorges Group brought the reproduction and release activities to the Heishui River.

The Heishui River is relatively rich in aquatic biological resources and is an ideal habitat for schizothoracic fish and cobia. Carrying out fish breeding and release can increase the fish resources in the river and give full play to the protective role of the Heishui River water habitat on related endemic fish.

The world's largest clean energy corridor has brought new vitality to the ancient river, and this vitality will also be shared with the water elves living here.

Bird migration——

In April, a large number of photography enthusiasts gathered in Dongchuan and Qiaojia areas.

The spring sunshine here is different from other places and has begun to show its power. But this does not affect the enthusiasm of photography enthusiasts. They all point their "long guns and short guns" at the trees in the distance, just to take pictures of the chestnut-throated bee-eater taking a rest here.

The Chestnut-throated Bee-eater is known as "China's most beautiful migratory bird" and is an old friend of the Jinsha River. Its fur exudes a metallic luster, its throat is chestnut-red, and it is brightly colored. It has a graceful flying posture and is extremely ornamental.

Chestnut-throated Bee-eaterPhotography: Zhao Jian

The hot weather is a test for photography enthusiasts, but it is a blessing for the chestnut-throated bee-eater. The unique dry and hot valley climate along the Jinsha River creates the temperature and geological conditions suitable for the reproduction of the chestnut-throated bee-eater. In April, they will come together, set up camp on the steep sandy cliffs along the Jinsha River, and breed their offspring. During this period, the chestnut-throated bee-eater can often be seen flying in Dongchuan and Qiaojia.

This beautiful bird was listed as a second-level protected wild animal in the "National List of Key Protected Wild Animals" in 2021. Also in 2021, they formed an indissoluble bond with the Baihetan Hydropower Station.

Time goes back to two years ago. On the eve of the Baihetan Hydropower Station filling the reservoir, nearly 100,000 migrants moved out of the reservoir area. While the migrants' new life began, another relocation operation was also in full swing.

After observation, the builders found that some nests of chestnut-throated bee-eaters were located below the flood line of the Baihetan Hydropower Station reservoir. Therefore, the Three Gorges Group, together with the Ecological and Environmental Research Center of the Chinese Academy of Sciences and Yunnan University, formed a working team and jointly launched an "immigration operation" for the chestnut-throated bee-eaters.

Liu Jiang, an associate researcher at Yunnan University who was invited to participate in this "immigration action", has been paying attention to the habitat of the Chestnut-throated Bee-eater in the Jinsha River Basin since 2012. He was surprised and moved that the Three Gorges Group came to him for this bird.

On one side is an enterprise that has been deeply engaged in the field of hydropower engineering construction for decades, and on the other side is an expert and scholar who has been engaged in ecological and environmental protection for a long time. The powerful combination quickly came up with a solution, which can be simply summarized as building a new home for them on the flood line.

On the flood line, several excavators are working non-stop. They spent half a month to artificially create a large area of ​​chestnut-throated bee-eater habitat. After visiting and investigating, the working team found that the environmental factors here are very suitable for the chestnut-throated bee-eater.

Artificial nest of chestnut-throated bee-eater (data picture)

The chestnut-throated bee-eaters that have moved away from their old home only need to fly upstream about four kilometers to find a perfect location - there is their favorite sandy cliff, and everything is the same as their original home.

The observation results in 2021 showed that the chestnut-throated bee-eaters safely passed the breeding season of that year. The artificial nests on the flood line were favored by the "residents". A large number of chestnut-throated bee-eaters came to nest and successfully completed the breeding and chick-rearing process in their "new home". In 2022, the chestnut-throated bee-eaters also arrived as expected.

This year, in the first spring after the completion of the world's largest clean energy corridor, the skies of Dongchuan and Qiaojia once again welcomed the familiar figure of the Chestnut-throated Bee-eater. The birds flying freely enjoyed the beauty of the "corridor" and continued their wonderful fate with the Baihetan Hydropower Station.

Green Guest——

Before the Arbor Day in 2021, a group of new "residents" arrived at Liangzi Village, Shangcun, the construction site of the Baihetan Hydropower Station. The builders came in groups of three or five, looking at a newly planted tree with curiosity.

Image photography of the greening of Shangcun Liangzi Campground: Xie Lei

From their conversation, we learned that the tree attracted everyone's attention because it is 200 years old. It came from below the flood line of the reservoir in Ningnan County, Sichuan Province. There are 40 ancient trees moved in with it, and the ages of the trees are between 110 and 200 years old.

Transplanting and protecting ancient trees in the flooded area is an important part of the Baihetan reservoir bottom cleaning and terrestrial ecological protection work.

According to statistics, there are hundreds of ancient trees over 100 years old below the flood line of the Ningnan County reservoir. These precious biological resources received a precise relocation and resettlement plan before the water was stored. According to the plan, 40 of the ancient trees will be "settled" in the Baihetan Builders Camp. As the water storage date approaches, the ancient trees in the flooded area have set off one after another to start a new life.

Two years later, the centenarian trees that had left their original locations have sprouted again, adding more greenery to the Jinsha River Valley.

Ancient trees transplanted to the Baihetan builders’ camp. Photo by: Zhao Jian

The ancient trees are lush and green, and the "Beautiful Baihetan" is showing its heroic appearance. So far, the ecological restoration area of ​​the Baihetan Hydropower Station hub area has reached 3.9462 million square meters.

"Beautiful Baihetan" is a microcosm of the ecological and environmental protection achievements of the world's largest clean energy corridor. Today, the ecology of the "corridor" has been protected to the greatest extent, the environment has been significantly improved, and the forest and grass coverage rate in the hub project area has been improved compared to before construction.

In Xinmin Village, Wuding County, Yunnan Province, located in the Wudongde Reservoir District, drought- and flood-resistant "amphibious" plants such as pond cypress and Xanthium sibiricum are planted in the riverside area.

Because the Wudongde Reservoir is storing water, the water level here fluctuates frequently, which is not suitable for the growth of conventional plants. Generally, it takes a long period of time for plants that adapt to the water level changes to grow. Such areas are called drawdown zones. Carrying out the restoration of drawdown zones and building ecological communities in advance has been an ongoing research since the Three Gorges Project.

The dry and hot valley climate in the Wudongde and Baihetan reservoir areas has brought greater challenges to the restoration of the drawdown zone. Many plants, including pond cypress, mulberry, and Cynodon dactylon, were selected to join the drawdown zone restoration experiment due to their strong adaptability. They lived up to expectations and showed good growth after being invited to "live in" the restoration trial phase. They are currently receiving maintenance, monitoring and evaluation.

It can be foreseen that in the near future, the dry and hot river valley drawdown zone will be covered with greenery, giving new connotations to the beauty of the corridor.