by Mao Pengfei, Nguon Sovan

STUNG TRENG, Cambodia, April 20 (Xinhua) -- In early April in Sesan District of Stung Treng Province, Cambodia, the reservoir of Lower Sesan 2 Hydropower Station was sparkling with water merging with the azure sky.

On the right bank of the dam, a clear stream flows through the woods downstream of the saddle dam. This is the nature-like fishway of the station.

The 781-million-U.S. dollars project is a joint venture among China's Huaneng Hydrolancang International Energy holding 51 percent of the stake, Cambodia's Royal Group owning 39 percent and Vietnamese EVN International Joint Stock Company possessing 10 percent.

The 400-megawatt dam is the largest and the seventh one built by China in Cambodia. The Lower Sesan II dam, 56.5 meters tall, covers a 36,000-hectare plot.

Yan Xiang, deputy general manager of Hydro Power Lower Sesan 2 Co. Ltd., who is in charge of the operation of the hydropower station, said: "We have always been adhering to the policy of 'protecting in development and developing in protection', attaching great importance to the natural and ecological environment so as to provide green energy to Cambodia and the Belt and Road cooperation."

When talking about the fishway, engineering manager Nong Zuguan, who is responsible for the construction management of the fishway, said "We made it into a natural fishway to fit into the surrounding environment, like a natural river. This is the way the fish came home."

For the 2,900-meter long fishway, the maximum water level difference between the upstream and downstream is 26.5 meters. While the bottom width of the fishway is 4-5 meters, rest pools are set every 800 meters to better facilitate the fish make their journey.

The construction of the fishway began in April 2017 and it had been put into use since the end of the same year.

Speaking of the intention of building a fishway, Mu Wanpeng, director of the Safety and Environmental Protection Department of the Station, said that according to the environmental impact assessment of the project, there are 34 kinds of long-distance migratory fish in the area of the project. In order to meet the needs of these migratory fish and maintain the diversity of fish in the area, the company initiated the proposal to the Cambodian government to build the fishway.

"In order to verify the effectiveness of the fishway, the company has carried out regular inspections twice a month since the operation," Mu Wanpeng said. In addition, the company is currently planning to invite professional teams to carry out fishway observation and research projects.

Mu said that environmental protection work has always been the top priority of the project. The project has detailed regulations on atmospheric protection, production and domestic sewage treatment, soil and water conservation, etc. Fishway construction is only a part of it.

"We use underground buried sewage treatment facilities to effectively treat domestic sewage, and the treated wastewater can be recycled for gardening irrigation," Mu said.

The office and and living area of the station is like a small garden with carpets of green grass, and diversified picturesque sceneries.

Eng Phirong, director of Stung Treng Provincial Department of Environment, said Lower Sesan II Hydropower Company has paid particular attention to environmental protection, complying with all requirements in the Environmental Impact Assessment paper.

"My colleagues and I have visited the hydropower station regularly to inspect the management of solid and liquid wastes and we found that the company has managed them very well," he told Xinhua in a recent interview.

For the liquid waste, the firm has a reservoir to store it for treatment before releasing it into the river, Phirong said.

"We have also taken water samples at the hydropower station for a test at the Ministry of Environment's laboratory, and found that there is nothing changed, the quality of water is good," he said. "In sum, I can say that the company has paid high attention to environmental protection because the quality of water and air there is pretty good."

The reservoir, like a sapphire in its natural settings, now provides green energy for Cambodia's economic and social development. "We must protect the ecological environment of the Sesan river basin and guard the blue sky and the green river here," said Yan.