Who can help me introduce the drainage system of the Summer Palace? It is said to be amazing!

Drainage system of the Summer Palace (explanation)

One day more than 300 years ago, a group of construction workers were taken to the foot of Yuquan Mountain in the suburbs of Beijing and started a huge project. They work day and night. Finally, in the twenty-ninth year of Qianlong, a large-scale natural landscape garden with Wanshou Mountain and Kunming Lake as the main body, the Summer Palace, rose from the ground. She is beautiful and dignified, surrounded by mountains and waters, and is the peak of her separation from the palace. However, even the people who built her don't know that under her elegant lakes and mountains, she carries some unknown secrets.

Title: "Secrets under Lakes and Mountains"

Aisingiorro Hongli, Emperor Gaozong Qianlong of the Qing Dynasty, was the fourth emperor after entering the Qing Dynasty. He pushed the prosperity of the Qing Dynasty to the peak, and also built the Yuanmingyuan and the Summer Palace, the two most praised gardens in the Forbidden City. However, the birth of the Summer Palace was not as smooth as expected. The most important reason is that Emperor Qianlong built Yuanmingyuan, which is called the Garden of Ten Thousand Gardens. Later, he told the world: "Later generations will not give up this point and spend a lot of money to create a garden, but I am deeply grateful to the French emperor for his thrift." He announced that he would never build a garden again. However, what caused Qianlong to risk being accused by everyone in the world and spend huge sums of money to build this world-famous royal garden in just six years? Is it really "the joy of mountains and rivers, can't you forget it?" What else, other meaning?

According to historical records, the 16th year of Qianlong, that is, the first year when the Summer Palace broke ground, coincided with the 60th birthday of Queen Mother Niu Zhilu. Qianlong, who has always been "ruling the world with filial piety", took this opportunity to rename the original Wengshan Mountain Wanshou Mountain as a birthday gift for his mother. However, is it really just a birthday that can make the emperor dare to go back on his word and build a new building?

We looked at the map of the Summer Palace when it broke ground and were surprised to find that the construction of the Summer Palace was unprecedented. The original water surface of Kunming Lake was only a quarter of that of the present, but after the completion of the Summer Palace, Kunming Lake was widened and deepened, and the water surface was greatly increased, forming a broad vision; Dredged silt was piled up on the mound originally called Wengshan Mountain, and according to the meaning of Qianlong, a unique Wanshou Mountain was formed. Therefore, the whole construction process of the Summer Palace is a process of digging lakes and piling mountains. Although this is not unprecedented in the history of landscape architecture, it is also rare. It's just for mom's birthday, so why be so extravagant. Is it really that Emperor Qianlong expressed his affection for the landscape of the West Lake and wanted to imitate the landscape of the northern mountains and southern waters of Hangzhou in the south of the Yangtze River in Beijing, and then build a West Lake clause? Or, did Emperor Qianlong just use his birthday as a cover and have another purpose?

By chance, we found a strange phenomenon of Beijing topography, which gave us great inspiration. Beijing is located in the North China Plain, and the roads in the whole city are gentle, but not completely level. The whole region presents a subtle difference between the west and the east. Although there is only a gap of 30 meters at both ends, the whole city is orderly. The Summer Palace is the highest point to the west of this gentle slope. On the other hand, the water system of the Summer Palace is closely connected with other water systems in Beijing. The water in Kunming Lake joins Yuyuantan and Jishuitan through Wanquan River and Fuhai in Yuanmingyuan respectively, and runs through things in Beijing through Beihai, moat and Tonghui River. Two unique phenomena give us an important revelation, that is, water. Through the exploration of the water in the Summer Palace, it seems that we can find some unique things to explain the secret under the water waves and the unknown mentality of the emperor 300 years ago.

We entered the Summer Palace from the East Palace Gate and came to the square outside Renshou Hall. Soon, experts at the scene pointed out that the water supply and drainage method of this square depends on the height difference of the ground to make rainwater flow downwards, and a rainwater outlet is set at the lower part of the courtyard, and finally it is discharged to the outside of the courtyard through a concealed pipe. What puzzles us, however, is that such a large square has chosen this way of using slope drainage, and rainwater will inevitably cause cumulative erosion to the square, which is obviously unscientific. After consulting the information, it was found that the whole square was covered with a lot of vegetation, and only the middle section was used for walking. After the rainwater is buffered by vegetation, there is little power left, and the drainage effect can be naturally completed. This incident makes us suddenly realize that the Summer Palace today is completely different from the situation in the Qianlong period. If you want to get the truth of that year, you must restore everything.

Passing through the palace at the entrance of the East Palace, I came to a rockery made of bluestone, which separated the palace area of the Summer Palace from the lake area and played a role in shielding the scenery. Rockery composed of large pieces of bluestones seems to be forcibly staggered, attracting people to the depths. But judging from the height of the ground here, it happens to be a high slope, which has become the watershed between the Lake District and the Palace District of the Summer Palace. Before that, the water flowed out of the East Palace gate along the slope formed by the palace and gathered in the crescent river outside the gate; After that, water flowed into Kunming Lake in a series of ingenious ways.

After the rockery, the time suddenly became clear, and the beauty of Kunming Lake swept away the formality of the palace area before, blending the lakes and mountains into the sight of tourists. Cypress trees have framed the scenery of the lake area into moving pictures, and unconsciously, these pictures have also diverted the attention of tourists. At the foot of tourists, the water also flows along the height difference of the ground and gathers in Kunming Lake.

We came to a place by the lake called Zhichun Island, a duck-shaped island, which is the best scenic spot in the Summer Palace. We took Su Dongpo's famous sentence, the duck prophet who warmed the river on the riverside. On Zhichun Pavilion, we divide the whole Summer Palace into four parts: the buildings under the mountain, the buildings on the mountain, the wild areas between the mountains and the long dike area by the lake. According to the geomorphological characteristics of different buildings, the distribution of water system is studied, and then the secrets of that year are revealed.

Buildings under the Mountain (Subtitle)

We turned back along the original road and came to the mountain complex, which is a courtyard composed of a series of buildings, such as Yulantang, Yiyun Pavilion and Jiaqian Tower. In the yard, we can easily find a cross-shaped road, and the center of the road is the center of the yard. Through the ingenious design of the road, the courtyard has become a structure with high middle and low periphery, and the water flows into the surrounding manhole along the height of the ground. However, where is the water flowing into the sewer discharged from?

With this question, we searched along the courtyard and unconsciously came to Kunming Lake, but found no place to drain. Did the water disappear into the yard by itself? Or, use a deep and long pipeline to transport it directly to the outside of the Summer Palace?

Suddenly, an eagle-eyed man found a brick with some gaps on one side. After careful observation, we learned that the water was collected into Kunming Lake unintentionally by tourists through the gaps between bricks on the wall. Seeing all this, we are not only full of admiration for the designers of the Summer Palace, but also full of curiosity about the construction purpose of the Summer Palace.

Buildings on the Mountain (Subtitle)

The buildings on the mountain are mainly composed of a series of buildings, such as the Foreigner Peak, the Humorous Garden, the picturesque world tour, the Paiyun Hall and so on. These buildings are scattered all over the mountains. Facing the impact of water flow, they all show their magical powers and use all available resources to form a set of regular and systematic drainage methods.

The first weapon: blocking (subtitle)

Outside Yang Renfeng, a long ditch lies across the building, and the water flowing through it is intercepted outside the building and flows into Kunming Lake at the foot of the mountain along the direction of the ditch.

The second weapon: block (subtitle)

On the mountain road, these humble stones can be seen everywhere. Sometimes tourists are tired and can sit down and have a rest. These stones are indispensable water retaining stones for drainage of mountain buildings. When they rush down, they block the big water flow, effectively reducing the kinetic energy of the water flow and alleviating the power of the water flow.

The Third Weapon: Powder (Subtitle)

In addition to these large water retaining stones, there are some slender and towering stones in the mountains. Although these scattered stones can not directly hinder the downward rush of water flow, they can divide large water flow into small water flows and play a role in dispersing power. This is the effect of diversion.

The fourth weapon: storage (subtitle)

Many times, the water will carry a lot of sediment, and if it is directly discharged into Kunming Lake, it will cause sludge deposition. Therefore, a small reservoir is often placed next to a large water body to precipitate this part of the water with sediment and then send it to the large water body through a pipeline. In mountain buildings, the small foot gourd river plays a role in storing water. It is its existence that keeps the bottom of Kunming Lake at a relatively stable level, so that it will not be dredged every year.

Fifth Weapon: Platoon (Subtitle)

After the treatment of the first four weapons, the stagnant water still flows into the open waters through pipelines or surface runoff, which is the process of drainage and the last weapon.

The building area on the mountain is blocked, blocked, divided, stored and discharged, which will flow into Kunming Lake in an orderly manner.

Interesting Things in Shan Ye (Subtitles)

The back hill of the Summer Palace is a mountain with almost no buildings, where small animals live freely and are full of natural interest. In what way do these places guide their water flow direction?

We happened to meet a group of students from Beijing Forestry University in Houshan. Knowing our intention, the teacher Wang Peiyong, who led the team, gladly walked with us and acted as a commentator in Houshan.

Dialogue with Teacher Wang (introduction of Houshan)

We explored along the mountain road and found a very unique valley.

Dialogue with Teacher Wang (Gu Fang, Shan Shi)

It turns out that Houshan returned the water to Houxi River in the north in this way.

After studying the building area under the mountain, the building area on the mountain and the wild area behind the mountain, we suddenly found a very unique phenomenon. All the water in the Summer Palace flows into Kunming Lake in front of the mountain and Houxi River behind the mountain in various ways, and Houxi River is connected with Kunming Lake. For an instant, we seemed to remember something. With this unformed question, we came to the last river embankment area for our final exploration.

We found a very interesting phenomenon on the long embankment by the river. The edge of the whole river bank is deformed inward. What makes this long embankment so strange? Did the builders of the building deliberately pile it up? After analysis and research, we found that it was the cold expansion and heat contraction of the river. Every winter, the river freezes and the river area increases, but in summer, it returns to its present state. Time and time again, every year, the river bank is pressed into its current curved state. At that time, we not only admired the solidity of this dike. However, this embankment is only a few meters wide. Why build such a narrow bank to withstand such strength? According to experience, only dams will adopt this unique structure.

We walked along the lake and found an interesting door. We explored it with great interest and found that there was an abandoned stone gate inside, and the water in Kunming Lake slowly flowed out along the stone crack. In an instant, it seems that all the problems have been solved. It turns out that the whole Kunming Lake is a reservoir. Through the ingenious design of the Summer Palace, it collects water into the lake, and then flows to every corner of Beijing through the Crescent River and Wanquan River. The whole long dike is the dam of this waterway, and the gate is the abandoned Erlongmen.

We came to the fence outside the gate of Erlong Mountain and found that a line outside the wall formed a gap inside and outside the courtyard, while outside the garden was an abandoned reed. After historical research, it was once a large paddy field, and this discovery once again confirmed our speculation.

The purpose of Qianlong's construction of the Summer Palace was to irrigate this paddy field that provides Beijing's staple food and the water system that connects the whole of Beijing. The imperial garden on the surface of the Summer Palace is just to cover up the real purpose of its reservoir. This is the real reason why Emperor Qianlong is willing to accept the responsibility of the whole people.

Today, the Summer Palace has become a famous tourist attraction at home and abroad. Every year and every day, thousands of people come here. Although everyone is praising the gardens and landscapes here, they have not found the hidden secrets under the lakes and mountains. It is the attachment and love of wise men and gentlemen to the world.