Central Radio Network | Dali, Yunnan: Multiple measures taken to protect the clear waves, Erhai Lake transparency reaches a 20-year high

Dali, August 16th (Reporter Wei Wenqing Intern Reporter Bai Xinran) In Dali in August, the clear waves of Erhai Lake ripple, and the white seaweed flowers sway with the water, like a dynamic landscape painting. The blooming of seaweed flowers, known as the "touchstone of water quality", is not only a unique scenery, but also witnesses the solid achievements of Dali Bai Autonomous Prefecture in the protection and management of Erhai Lake. In recent years, Dali Prefecture has always kept in mind the mission of "protecting Erhai Lake well", coordinated the management of water resources, water environment, and water ecology, coordinated production, life, and ecological "three life" spaces, and promoted the protection of Erhai Lake to a higher level.

The rippling seaweed flowers in Erhai Lake are a sign of good water quality. (Photo by Bai Xinran, an intern reporter at China National Radio)

It is reported that in terms of interception and control of pollution, Dali Prefecture has promoted the Erhai Lake ring pollution interception and control project in accordance with the principles of "taking advantage of the terrain, closing gaps, combining pipes and channels, collecting and treating in sections, centralized treatment, one-time planning, and step-by-step implementation". As of June 30, 2025, the cumulative treated water volume of the Erhai Lake Ring Water Interception Project (Phase I) has reached 123.2417 million tons, reducing chemical oxygen demand (COD) by 13511.55 tons, ammonia nitrogen by 1820.5 tons, total nitrogen by 2809.41 tons, and total phosphorus by 438.77 tons. The project introduces distributed sinking regenerated water ecosystem technology and is equipped with a smart supervision system to achieve data transparency throughout the entire process of sewage collection and treatment. The monitoring results show that since the start of the project in 2016, the water quality of Erhai Lake has continued to improve, and it has been rated as "excellent" for three consecutive years from 2020 to 2022. According to data from the Yunnan Provincial Department of Ecology and Environment, the transparency of Erhai Lake has increased from 1.79 meters in 2021 to 2.29 meters in 2022, reaching the highest level in nearly 20 years.

With the development of technologies such as big data and the Internet of Things, digital means are becoming an important support for the governance of Erhai Lake. The "Digital Erhai Lake Supervision Service Platform" built in Dali Prefecture integrates six functional modules: data center, decision support, collaborative management, information services, business applications, and intelligent perception. It comprehensively analyzes the terrain, water quality, and inflow of water into the lake, and has the ability to provide short-term warning and mid-term prediction, tailoring a "governance plan" for Erhai Lake. After the platform is put into operation, first-hand data on Erhai Lake protection can be obtained in real time, making governance decisions more accurate.

China Water Environment Group's Ancient City Submerged Reclaimed Water Plant, after sewage collection and treatment, becomes clear again (Photo by Bai Xinran, Intern Reporter of China National Radio)

Lake governance is a global challenge, and the establishment of a scientific evaluation system is particularly crucial. In recent years, the Yunnan (Dali) Research Institute of Shanghai Jiao Tong University has collaborated with research institutions such as the Chinese Academy of Environmental Sciences to develop and launch the "Erhai Lake Index" evaluation system. This system breaks through the limitations of previous single physical and chemical indicators, and sets eight indicators including sewage treatment, garbage disposal, water quality monitoring, aquatic flora and fauna, and lakeside landscape from the four dimensions of "cleanliness, clarity, ecology, and sharing", forming a systematic assessment of aquatic ecology.

Taking seaweed flowers as an example, they once disappeared, but now they have resumed growth, which has intuitive indicative significance for improving water quality, "said Wang Xinze, a researcher at the School of Environment and Engineering, Shanghai Jiao Tong University. As part of the "Erhai Lake Index", the distribution and growth status of seaweed flowers are included in quantitative indicators, reflecting the positive changes brought about by the protection and management of Erhai Lake. The application of the "Erhai Lake Index" will provide more scientific support for the high-level protection of Erhai Lake and the sustainable development of the watershed.

Facing the morning light of August, the lake and the sea of flowers complement each other beautifully. The clear waves and blooming seaweed flowers of Erhai Lake are not only beautiful natural gifts, but also vivid footnotes to the effectiveness of Erhai Lake governance. The relevant person in charge of Dali Prefecture stated that the next step will continue to coordinate the promotion of watershed protection and ecological restoration, allowing the beautiful painting of "Cangshan without ink for thousands of years, Erhai Lake without strings and ten thousand guqin" to continue to expand.

News source: China National Radio