"We don't produce water, we are just nature's porters." Where is the water being ported?

On April 22, 2023, the Science Popularization China Starry Sky Forum, with the theme of "Cherish the Earth and Share Beauty Together", invited 5 scientists from related fields to talk about the knowledge of the earth and nature from the perspectives of geology, geography, geophysics, and astronomy.

Shen Leyi, Director of the Ecological Restoration Division of the Planning and Natural Resources Bureau of Hangzhou City, Zhejiang Province, and the Most Beautiful Nature Guardian of 2021, gave a speech: "Protecting Green Waters and Green Mountains"

The following is an excerpt from Shen Leyi’s speech:

In addition to the beautiful West Lake, Hangzhou also has a nationally famous scenic spot - Chun'an Thousand Island Lake.

Chun'an Qiandao Lake, also known as Xin'anjiang Reservoir , was built in 1955 by intercepting the upper reaches of Xin'anjiang River in order to build Xin'anjiang Hydropower Station. Xin'anjiang Hydropower Station is China's first large-scale hydropower station designed, equipped and constructed by itself . It is known as the "experimental field of the Three Gorges of the Yangtze River" and is a monument in China's water conservancy and power industry.

Xin'anjiang Hydropower Station. Copyright image, no permission to reprint

After the Xin'anjiang Reservoir was filled with water, 85 mountains and the two counties of Chun'an and Su'an in Zhejiang Province were submerged. The former mountains became 1,078 islands, the largest of which is Jieshou Island, with an area of ​​21.7 square kilometers, and the smallest is Longzhu Island, with an area of ​​2,500 square meters.

Hidden deep underwater are two thousand-year-old ancient cities, "Shicheng and Hecheng". Photo courtesy: Shen Leyi

01

The lake with the most islands in the world

In 2009, Chun'an Qiandao Lake was selected into the world record as the lake with the most islands in the world.

There is also a little story behind this.

Some people say that there are 1,800 islands in the Thousand Islands Lake in Kingston, Canada. Chun'an Thousand Islands Lake is not the lake with the most islands in the world. Here we need to explain how big an island needs to be to be included in the statistical scope of Thousand Islands Lake.

When the water level of Qiandao Lake is 108 meters, the islands with a land area of ​​more than 2,500 square meters above the water can be included in the statistics. In other words, islands smaller than the Longzhu Island mentioned above cannot be included in the Qiandao Lake.

However, there are many mini islands smaller than 2,500 square meters in Qiandao Lake. If these are included, the number of islands of all sizes in Qiandao Lake will reach more than 2,000. Therefore, no matter which statistical method is used, Qiandao Lake is well-deserved.

Qiandao Lake. Copyrighted image, unauthorized reproduction

02

How to protect the "most beautiful water in the world"

In addition to its many islands, Qiandao Lake is also famous throughout the country for one thing - water.

There is a famous advertising slogan: "We don't produce water, we are just nature's porters." The first water this company transported was from Qiandao Lake.

Why is the water in Qiandao Lake so good? Because Qiandao Lake is a super-large reservoir in my country and the largest artificial freshwater lake in the Yangtze River Delta. The normal reservoir capacity is 17.8 billion cubic meters, equivalent to 3,184 West Lakes, with a water area of ​​567 square kilometers, an average depth of 34 meters, and the deepest point reaches 108 meters.

The water of Qiandao Lake is pure and sweet, with a maximum visibility of 12 meters. It contains natural mineral elements such as calcium, sodium, and magnesium, and is naturally weakly alkaline . Therefore, its water quality always remains at the forefront of key lakes and reservoirs in the country, and is praised by people as "the most beautiful water in the world."

In 2019, Zhejiang built the Qiandao Lake water distribution project, officially supplying water to more than 13 million people in the downstream cities of Hangzhou and Jiaxing. It can be seen that its status as a drinking water source is very important.

Photo courtesy: Shen Leyi

At the same time, Qiandao Lake, a 5A-level national scenic spot, has a county population of 460,000 and receives more than 18 million domestic and foreign tourists every year.

Compared with natural lakes that are thousands or tens of thousands of years old, Qiandao Lake, an artificial lake, faces the difficulty of being highly sensitive to water pollution due to the high intensity of human activities and relatively insufficient ecological self-purification capacity.

1. Agricultural non-point source pollution, including fertilizer application, pesticide spraying, domestic sewage, and ship sewage, all of which may lead to water quality deterioration, even eutrophication, and algae outbreaks;

2. In the early years when the economy and society were developing extensively, holiday apartments and other buildings near the lake occupied the water area, threatening the ecological security of the water environment, and some biological habitats in the basin were destroyed, posing a threat to biodiversity.

Photo courtesy: Shen Leyi

How to protect this beautiful lake is a difficult problem that needs to be solved urgently.

In 2018, we implemented the national pilot project for ecological protection and restoration of mountains, waters, forests, farmlands, lakes and grasslands at the source of the Qiantang River. The Qiandao Lake water environment protection and restoration project is an important part of it. Through three stages of source control, process control and end-of-pipe management , we carry out systematic management of the entire process.

As a nature guardian, I deeply feel that the protection and restoration of the integrated ecology of mountains, waters, forests, fields, lakes, grasses and sands is related to the construction of ecological civilization, the national ecological security, and the sustainable development of the Chinese nation. This is a systematic project, a national project, and a "virtuous" project that requires everyone's participation.

Starting from "me", starting from today, starting from the little things around us, each of us can become a guardian of nature and protect our green home.