Author and Researcher Jiayang Song on the Future of Yunnan’s Dianchi Lake

By That's, January 23, 2020

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During the Chinese Cultural Revolution, Puren Tan, the Political Commissioner of Kunming’s Military District and the Director of Yunnan’s Revolutionary Committee (a position similar to the premiere), superstitiously believed that his life was filled with the so-called “fire element,” and therefore was restrained by the vast “water element” in Yunnan. As intellectual as he was, he decided to use the reason of increasing farming yield to call up 100,000 citizens to fill in the wetlands around Dianchi Lake’s inner sea (草海). 

A wetland is vital to a lake’s ecosystem as it acts like a lake’s kidney: It filters and prevents harmful sediments (such as nitrogen and phosphorus) from accumulating, which can cause algae blooms. Unsurprisingly, with much of the wetlands gone, Dianchi was not able to filter out the excessive sediments later expelled by polluting industries. As a result, blue-green algae blooms in Dianchi every summer to this date. 

Although the local government has been encouraging the ecological recovery of Dianchi through the ideology of ‘returning farmland to the wetland’ in the past ten years, the water quality only meagerly improved. It is possible to say that if the wetlands remained untouched, Dianchi’s eutrophication (the unwanted growth of algae caused by excessive nutrients in a body of water) would have been less severe. 

Industrial pollution was and still is a primary point source polluting factor (an identifiable and locatable source) that contributes to Dianchi's eutrophication. In the late 20th century, Yunnan’s officials had not yet realized the importance of preserving the environment. Therefore strict environmental regulations were not implemented. 

During these decades, polluting industries, such as Kunming Chemical Fertilizer Plant, Kunming Phosphate Fertilizer Plant, Fubao Paper Mill and Yunnan Printing House, directly released their industrial wastewater into the lake without basic treatments. Since either the product of these industries or the method of production of their products contained nitrogen and phosphorus, the release of their industrial wastewater increased Dianchi’s level of nitrogen and phosphorus, which gave rise to the sickening algae bloom today. These industrial wastewaters were also rich in sodium tripolyphosphate, carboxymethyl cellulose, oil stains and various alien microorganisms. Upon entering the water system, these additives caused the ecosystem to collapse, killing native fish species who used to consume the algae and kept the algae population under control. 

Thanks to both the citizens and the government for their efforts in valuing Dianchi’s water issues, the majority of these industries had been closed down, but the spontaneous birth of multiple golf courses took up the original wetlands. Without the wetlands, Dianchi is unlikely to regain its original beauty. 

Kunming’s immense population bloom also endangered Dianchi’s water quality. Dianchi’s water became the most polluted in the 1980s and 1990s, which was at the same time Kunming’s population boomed due to the Chinese economic reform. 

According to the United Nations – World Population Prospects, Kunming’s population increase spiked to 8.61% in 1983 from 1.75% in 1982. This was especially bad for Dianchi for two reasons: Firstly, Kunming is located north of Dianchi, and Dianchi’s water flows south, and secondly, the citizens were poorly educated and had absolutely zero knowledge about pollution. In the 1980s, Kunming’s municipal wastewater was directly released into Dianchi. Wastewater included human feces and urine, which was incredibly rich in nitrogen – a great source of nutrition for the algae. Also, since the city was located northeast of the lake and the water flows south, the nutrients accumulated throughout the entire lake, even polluting water sources for cities located south of Dianchi. 

Additionally, the citizens of Kunming did not have environmental awareness. The protection of Dianchi was and still is not emphasized in local textbooks. Kunming locals rarely visit Dianchi nowadays for entertainment as there are better-protected lakes nearby such as Cuihu and Yeyahu. Therefore, the new generation of Kunming is less aware of Dianchi’s crucial status in Yunnan culture. 

Furthermore, the local government’s effort to raise public awareness is meager. The environmental propaganda posters have no correlations with the environment – the latest one exhibits a pink pattern with “Human, environment, co-exist” written under it, having absolutely nothing to do with water protection. 

Up to 2015, China has spent more than RMB20 billion to revive Dianchi’s water quality, but it has only improved slightly. The local government’s attitude towards the rejuvenation project correlates with this. Upon visiting Dianchi, it can be observed that local elders are volunteering to clean Dianchi on the government’s behalf. These voluntary actions delay the clean-up as these elderly volunteers have never been trained nor do they participate in the project for a long time. In short, these cleaners are just unskilled cheap labor that harm Dianchi’s water quality. In conclusion, in order for Dianchi’s water quality to recover, the government must bring the citizens’ hearts together to take environmentally friendly actions on the municipal level. 

Dianchi’s natural attributes also contribute to its eutrophication. Firstly, Dianchi was a product of a convergent boundary clash: It is located among mountain ranges, therefore there is a rain shadow effect (when water vapor in the moist air condenses to form clouds and produces rain as it rises with the mountains). This rain falls on the nearside of the mountain, causing the air that continues on the farside of the mountain to be dry. There is also over-forestation (plant roots hold the soil together; without them, soil run-off occurs more often when water runs through the earth), causing nitrogen-rich mountain soil to be washed into the lake more often, increasing nutrient levels in the lake. 

Unluckily, Dianchi Lake has been shrinking since its existence, making the lake relatively shallow (easier for sediments to accumulate) and its surrounding soils extremely rich in nutrients. As a result, when the farmers decided to fill the surrounding wetlands in order to grow crops, the soil turned out to be so fertile that it murdered the grown crops. Even worse, the irrigated water was lead directly into the lake without basic treatments, making the lake water excessively rich in potassium and nitrogen. Once they entered the lake, the nutrients accumulated because of the semi-closed Dianchi’s natural water cycle cycling extremely slow. 

Kunming is an awkward city. As the capital of Yunnan, it has the mission to lift Yunnan’s economy, but at the same time, due to its natural beauty, it is a significant city for tourism. Being the provincial capital, it cannot entirely become a tourist city, like Lijiang or Dali, but being a transition city between others in Yunnan and the rest of the world, Kunming developed many ‘fast’ tourism specialties for visitors to experience without having to spend much time. The flower industry is an iconic example. Kunming is honored to be the ‘flower city’ of China – it sells flowers by kilograms! The Dounan Flower Market, with the overturn reaching RMB2.5 million daily and supporting 70% of all domestic markets, lays just beside Dianchi. A total of 138 square kilometers of flower greenhouses exist just northwest of Dianchi. Before regulations would be gradually set in the past 20 years, these flower farmers, mostly environmentally unaware due to lack of education, would release the nitrogen- and phosphorus-rich irrigated water into the lake directly. Years passed and the regulations were set, but the nutrient had naturally sedimented into the soil. Today, the nutrients erode into Dianchi during rainy seasons and usher algae blooms later. 

With the majority of the wetlands gone, Dianchi Lake was not able to commend the introduced polluting water and run-offs. The blue-green algae were then able to reproduce exponentially, causing Dianchi eutrophication pollution and making the lake water green every summer since. On the positive side, the Kunming municipal government has been implementing strict fines to districts that exceed the regulated pollution limit in their municipal waste. Dianchi’s eutrophication problem will be a continuous problem in the future. Although the improvement seems meagre, the future of the water is bright.

[Cover image via Pixabay]

Jiayang Song is an amateur author in the field of environmental science. Song obtained his highest degree of education from Richmond Secondary School – a high school in Richmond, British Columbia. He has one published original article in the finest journal in the area of his study. His research interests include (but are not limited to) environmental science, anthropology and history.

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