With the persevering efforts of a group of dedicated guardians, Erhai Lake in Yunnan is brimming with renewed vitality, enticing visitors with stunning scenery. 

The picturesque scenery of Erhai Lake in Dali Bai Autonomous Prefecture, southwest China’s Yunnan Province, has made it a popular destination for many tourists. About every ten steps along the shore of the lake, tourists are presented with a different view of nature. There are artistically designed local-style guesthouses on one side, and on the other side, lies the breathtaking beauty of Cangshan Mountain and Erhai Lake which, combined, create a mesmerizing natural masterpiece. Such paradise-like scenery is made possible thanks to the tireless efforts of a dedicated group of guardians protecting the lake.

Erhai Lake in Dali Bai Autonomous Prefecture, southwest China’s Yunnan Province.

Cleaning Up Erhai Lake

As the first sun rays of the day pierce through the clouds and light up Erhai Lake, Yan Bingqi, the lakeshore manager of Gusheng Village in Dali, has already started his busy day of work. Wearing a blue vest inscribed with the words: “Erhai Professional Salvage Team,” he retrieves aquatic plants that have washed up onto the shore, earning him the affectionate title of “Guardian of Erhai Lake.”

“I’ve been doing this work for the last decade. My daily tasks include cleaning up aquatic plants and dead fish that have washed up on the shoreline,” Yan explained. He manages an area of about seven kilometers along the lake shore. In addition to protecting wetland areas, he is also responsible for checking and managing drainage ditches. Every day regardless of the weather, he is faithful in carrying out his work. “I do this work for future generations,” he said with a smile.

Every afternoon, visitors can see piles of green aquatic plants neatly arranged along the lake walkway by workers like Yan Bingqi. These aquatic plants will be taken away by cleaning trucks to be recycled as organic fertilizer.

These lake guardians began working here as a part of the local government’s strong support for wide public participation in lake governance. “Our working approaches are grassroots-based, project-focused, and role modelling. We established a frontline command center and sent teams to 18 towns (sub-districts) in the Erhai Lake basin. Each month, we focus on one key project. By encouraging participation of the public and pooling resources including funds from all sectors of society, we’ve created a governance model that is based on participation and collaboration of the government, businesses and the general public and their sharing of benefits. In this model, the government takes the lead, businesses are the main players, and social organizations and the public participate together,” said Dong Liang, deputy commander of the Dali Erhai Lake Protection and Management and Basin Transformation Development Command.

According to Dong, to improve the quality of water flowing into the lake, he and his team strictly implement the river chief system and exercise ecological management of the rivers that flow into the lake. As a result, the water quality of all the 27 major rivers flowing into the lake has been rated excellent.

Yan Bingqi, known as the guardian of Erhai Lake, cleans up the lake shore.

Protecting Erhai with Technology

There are more than 10 expert teams in the Dali area who are dedicated to the research on lake protection. The Yunnan Dali Research Institute of Shanghai Jiao Tong University, located in the Haidong New District of Dali, was jointly set up by the Yunnan Provincial Science and Technology Department, Dali Bai Autonomous Prefecture People’s Government, and Shanghai Jiao Tong University. Based on the work of these teams, a national field scientific observation and research station for the ecological protection of Erhai Lake was officially approved for construction in 2021.

By making good use of the scientific research platforms of the Yunnan Dali Research Institute of Shanghai Jiao Tong University and the Erhai field scientific observation and research station, the local government has applied technologies to the lake management and is able to deepen research on water quality and ecological changes in the lake and tackle critical challenges such as agricultural source pollution control and sewage interception and treatment in the basin. A digital monitoring and service platform that integrates sky, air, land, and water sensing across the Erhai Lake basin is now in place, enabling the interconnection and deep integration of monitoring data, expert opinions, administrative decisions, and work measures. This provides scientific guidance for precision governance of the lake.

“It can be said we have technological ability to improve the environment around the lake from sky to land. In the sky, we have remote sensing images and unmanned-aerial-vehicle (UAV) patrols; on the water, we have scientific research vessels dedicated to protecting Erhai Lake; and then underwater, we’ve also introduced unmanned underwater patrol boats, which can measure water clarity and observe changes in benthic organisms,” explained Wang Xinze, president of the Yunnan Dali Research Institute of Shanghai Jiao Tong University. Wang then added that in addition to a range of online monitoring instruments, his team also has automatic monitoring stations for rivers flowing into the lake, helping the team better understand the surrounding conditions in real time.

With the help of these technological tools, the research team conducts three main tasks. First, it continuously tracks and analyzes the water quality and ecological changes of the lake, collects water samples, and analyzes water quality and algae one to three times a week in different areas of the lake. Second, it monitors the water quality of major rivers flowing into the lake, important drainage ditches, and the inflow and outflow of wastewater treatment plants in major nearby towns. This enables them to analyze the effectiveness of pollution reduction efforts across the basin. Third, it monitors projects like blue-green algae control and wetland ecological restoration once or twice each month to evaluate the effectiveness of ecological management measures, providing the decision-making basis for long-term conservation of the lake.

Additionally, the institute has developed several practical types of technology used in managing the lake and launched engineering demonstration projects to provide technical support for solving nonpoint source pollution issues in the Erhai Lake basin, water quality problems of the rivers flowing into the lake, and ecological restoration challenges in key lake bays, thus further enriching the technological reserves for supporting local conservation efforts.

“In 2003, the water clarity of Erhai Lake was just a little above 1.5 meters, and the total phosphorus concentration was 34 micrograms per liter, equivalent to Class III water quality. By 2023, the water clarity rose to around 2.1 meters, showing significant improvement. The total phosphorus concentration also dropped to 19 micrograms per liter,” Wang said. He noted that these achievements directly linked to the protection and management of the lake during recent years. It is obvious to the visitors that the water of Erhai Lake has become clearer, and its color turned back to deep beautiful blue.

Green Barrier Helps Maintain Ecological Stability

Signs and maps of the Erhai Lake Ecological Corridor have been set up along the lakefront to help visitors understand the history and environment around the lake. Along the way, visitors can observe shimmering waves and the stunning scenery of the lake surrounded by mountains. To restore the basin’s ecosystem, local authorities have built a 129-kilometer-long ecological corridor around the lake, which combines both ecological and scenic functions. The corridor connects the villages along the shore, greatly enhancing the sightseeing experience for visitors. It also creates a green ecological barrier for the lake.

“Significant changes have taken place over the past few years. Take our Gusheng Village for example, the number of visitors in the past was only in the hundreds, but now we have thousands. Visitors often comment about how much they enjoy the scenery here,” said Yan Bingqi, who has lived in the village for many years.

This ecological corridor has formed a pollution interception belt around the lake, significantly improving the biodiversity and the stability of its ecosystem. Meanwhile, local authorities have built an ecological monitoring passage, which helps workers monitor and manage the lake while also serving as a green trail around the lake. Thanks to this green barrier, the pollution load entering the lake has steadily decreased over the past years, and the overall water quality of the lake has remained stable.

The design of the Erhai Lake Ecological Corridor includes an ecological red line for the lake shore and a yellow line for the lake, dividing the Erhai Lake basin into a core ecological protection area, an ecological protection buffer zone, and a green development zone. This management strategy lays a solid foundation for clarifying the boundaries, principles, and requirements for long-term protection and management of the lake. Meanwhile, projects have also been launched to increase the greenage of the mountains on the eastern side of the lake and enhance the quality and efficiency of the basin’s wetlands and reservoirs, further strengthening their ecological barrier function.

Within the lake, the local government has also implemented a “grass, algae, fish, and silt” ecosystem restoration project, which includes regular fish stocking and release, ecological regulation, and aquatic plant planting. These efforts have effectively restored the ecological balance of the lake. In terms of pollution interception and treatment, according to data from the Dali Municipal Sewage Interception and Control Center, 12 sewage treatment plants, 3,400 kilometers of sewage collection pipelines, and 99,000 septic tanks have been built in the lake basin, establishing an initial sewage collection and treatment system for the entire basin. Since the system went into full operation on June 30, 2018, over 400 million cubic meters of domestic sewage have been collected and treated, ensuring the continued improvement of the water quality in Erhai Lake.

Recent years have witnessed the steady improvement in environment and water ecology of Erhai Lake. Ottelia acuminata, a native species growing in the basin, is an indicator plant as it requires high water quality and can only grow in Class III or even Class II water. With the improvement of water quality in Erhai Lake and its source waters, ottelia acuminata has made a comeback to the lake’s surface after disappearing for nearly a decade. Thanks to the wide public participation in Erhai Lake’s protection and management, Dali’s mother lake is brimming with renewed vitality and vigor.