Guizhou province in Southwest China has dismantled most small hydropower stations along the Chishui River, and installed new facilities in the remaining stations to maintain the essential water flow required to support the aquatic ecosystem's health.

The information was disclosed by Yi Geng, head of Guizhou provincial department of water resources, on the sidelines of the Eco Forum Global Guiyang 2025, a two-day event that concluded on Sunday.

Launched in 2009, the forum is the only national-level international forum in China dedicated to ecological civilization. The event this year is themed "Harmonious Coexistence Between Humans and Nature · Global Collaborative Development for Green Transformation".

As of the end of last year, all the 195 small hydropower stations the province planned to remove have been demolished, Yi said. To date, 339 kilometers of Chishui's sections in the province that suffered reduced water flow have been remediated.

For the 29 stations left, measures have been taken to ensure ecological flows through them, and the monitoring facilities have all been upgraded, he added.

With no dams along its trunk, the Chishui is the last free-flowing tributary on the upper reaches of the Yangtze. Traveling for 436.5 kilometers, it rises in Yunnan province, flows through Guizhou and joins the Yangtze River in Sichuan province.

Home to more than 160 species of fish, the Chishui is key to biodiversity conservation in the Yangtze River Basin.

Yi said these small hydropower stations in the Chishui were constructed starting from the 1950s and 1960s to alleviate electricity shortages in the surrounding areas.

These stations, while lighting up many families with poor access to electricity, have provided important impetus to local socioeconomic development.

"When they were constructed, however, these long-established small hydropower stations were built without taking into consideration the requirements for ecological and environmental protection," he said.

Especially after the turn of the new millennium, the adverse impacts of these stations have started to show up, jeopardizing local ecological environment and habitats for some rare fish species.

"These impacts have become increasingly prominent," he said.

As a result of the implemented measures, the density of hydropower stations along the Guizhou section of the Chishui has significantly decreased, facilitating the reconnection of all its over 20 tributaries to the main stem, he said.

"Monitoring conducted by professional institutions has revealed a rise in both the diversity of fish species and their populations," he added.