Yin Qingfeng was only surprised for a while and then agreed to the task assigned by Li Shimin to him.

After returning to the study room of the West Courtyard, he immediately found a pen ruler and started drawing. On the way back, he had already thought about it. Since he wanted to play, he would play with a big one.

What he wanted to play was a problem that had been highly valued in ancient Chinese urban construction: urban water supply issues.

As early as the Spring and Autumn Period and the Warring States Period, there was a strict theory about urban water supply: the mountains on both sides and the water flows around the river, and the inside was written as the canals, which were summed up by the river. In other words, ancient Chinese cities must be built in a water network area with canals across to facilitate water supply and drainage.

Chang'an City itself is known as "Eight Waters surround Chang'an", so the water source of Chang'an City can be said to be very rich.

When the Sui Dynasty built the predecessor of Chang'an City, "Daxing City", relying on the eight surrounding water veins, three canals, "Longshou Canal", "Qingming Canal" and "Yong'an Canal". After the founding of the Tang Dynasty, Huang Canal and Cao Canal were dug.

There are five water canals throughout Chang'an City. Then each main water canal is divided into several tributaries.

In this way, the entire Chang'an City has become an unprecedented city with water networks. From the imperial city gardens to various cities, you can see the rapid water flowing canals. This powerful water supply condition has not been seen in various cities in China before.

In addition to the canals, the well water in Chang'an City was also very developed, and there were wells in various lifangs. The daily drinking water of Chang'an citizens was mainly based on well water. Moreover, in Chang'an City at that time, water wells were also everywhere around the main palaces. In addition to providing drinking water, they also had fire emergency functions.

In addition to the canals and well water, Chang'an City has another water supply model: lakes. The well-connected Chang'an Canal also brings together many water flows to form large lakes, such as the release pond in the East and West City, the Longchi in Xingqing Palace, the Qujiang Pond in Furong Garden and the Taiye Pond in the Daming Palace, etc.

The water supply problem was successfully solved in the water supply problem, the most prosperous metropolis of the ancient Eastern world, and the most prosperous metropolis in the ancient Eastern world.

If someone has been to Suzhou and has seen Chang'an, he will definitely compare the two.

Unlike Chang'an's artificial axe, Suzhou, the center of the Jiangnan water network and the area with the densest rivers in the country, is completely a city built using the favorable conditions given by nature.

Not only are there rivers in Suzhou City, but there are also many lakes: Taihu Lake and Cao Lake in the west; Dianshan Lake and Cheng Lake in the east; Kuncheng Lake in the north; Yangcheng Lake, Jinji Lake and Dushu Lake in the middle.

Therefore, there is no water supply problem in Suzhou, nor is there a drainage problem.

But Chang'an is different.

The water supply system of Chang'an City can indeed be regarded as a successful example of city construction, but like modern Chinese cities, it does not pay attention to drainage.

In modern news, we often hear that a certain city has flooded after rapid rain. The root cause of this problem is not only to put a certain responsibility on the ancients, but also to cause short-sightedness to modern officials.

It describes the experience of Kou Zhong and Xu Ziling passing through the sewer or Yang Xuangan's secret passage in Luoyang City, but that is the author's nonsense. In the history of urban construction in China, drainage has never been paid attention to.

Including Chang'an and Suzhou, the drainage systems of ancient Chinese cities were actually mixed with the water supply system. Domestic wastewater and domestic water were flowing in the same canal and river. The result is conceivable.

The ancients did not pay attention to drainage. In addition to their lack of consciousness, they were probably related to their concepts. The ancients believed that above the earth was the world, and below the earth was another world. Since it was another aristocratic family, then as a human being in the world, don’t easily destroy it--in addition to the need to bury relatives.

In human history, modern Europeans really attached great importance to drainage issues.

In the 19th century, with the development of industrialization, Germany's urbanization process accelerated and the urban health system was overwhelmed. Cholera, typhoid fever and other diseases frequently broke out in German cities. Establishing a complete urban water supply and drainage system became an inevitable choice.

In 1842, under the planning of British engineers, Hamburg took the lead in building the initial urban drainage system and the first sewage treatment plant.

Although the equipment was simple at that time and did not completely solve the problem of water pollution, such a design concept was still milestone and was soon learned by some cities in Europe and the United States.

In 1867, Frankfurt became the first systematic modern sewer system. The system classified sewage, finally discharged into the river, and integrated with the drainage system of the entire city, greatly improving efficiency. It can be said that Germany opened a new starting point for the modernization of urban drainage systems.

When Yin Qingfeng was in the Eastern Palace, he advised Li Shimin to use the Furong Pool as the starting point to supply water to the city, but after he took the task, he changed his mind.

Not counting the garrison, the current population of Chang'an City is only more than 300,000. Moreover, among these more than 300,000 people, most of them are the families of those officials and their servants. There is not much surplus labor force that can be mobilized.

Similarly, there are not many free people around Chang'an City. The residents outside the city are more tenant slaves from the families of various nobles.

If construction starts at the same time inside and outside the city, after the "regulation" is lifted, it will be difficult to recruit enough personnel with official power - unless the nobles are willing to send out the tenant slaves.

But Yin Qingfeng is different. In addition to controlling the tenant slaves in Wutong New Village, he can also control the tenant slaves of the sixteen martial arts families.

Considering that September was a rainy season, he planned to start building the drainage system after autumn and then use five to six months to complete it.

The drainage system in the city is not as simple as digging a few sewers. It refers to the overall combination of drainage collection, transportation, water quality treatment and discharge facilities in a certain way. Only by combining drainage ditches at all levels, underground reservoirs, drainage gates, pumping and drainage pump stations and drainage discharge areas, etc. can a complete drainage system be built.

The working procedure of the drainage system is: after the excess water in the drainage area is transferred into drainage ditches at all levels or through underground reservoirs, it is then discharged from the drainage gate or extraction station to the discharge area.

Now the Nansipaifang District in Chang'an City is an unmanned area, either a cemetery, an orchard, or farmland. He plans to dig one or several of the cemetery into underground reservoirs, and then cover it with prefabricated boards and then backfilling it.

This approach is to improve the drainage system and save living space. As the Tang Dynasty became more and more prosperous, the Nansipai Fang District would sooner or later be full of people. Moreover, the excavated soil can be burned into bricks on the spot, which can save a lot of working hours.

After the drainage pipes and underground reservoirs are completed, the final discharge of wastewater must be considered.

The terrain of Chang'an City is high in the east, south and low in the west and north. The north is the imperial palace, so the drainage system can only find an exit from the northwest.

His plan was to restore the Kunming Canal of the Han Dynasty, the upper channel section would be the inlet canal in the city, and the lower channel section would be the discharge canal. In this way, a long underground passage would need to be dug.

With the dense underground drainage pipes in the city, he didn't know whether the Tang people could accept this behavior of "destroying Feng Shui". Although there was no such thing as "dragon vein" at this time, metaphysics was studied, and some people would come out to defeat him, a guy who "destroys the fate of the Tang Dynasty."

Fortunately, Lu Cai, a Feng Shui expert living in his family, could consult Lu Cai before he made a statement to Li Shimin. If Lu Cai thought it was okay, he boldly proposed to Li Shimin about building underground drainage pipes. If Lu Cai thought it was not possible, then convince Lu Cai and then let Lu Cai come forward to argue with the opponents.

After solving the idea of ​​the drainage system, Yin Qingfeng was wondering whether to create a "tap water" system in Chang'an City.

Flying canals are also called flying canals and troughs, also known as crossing bridges, elevated canals and water transport bridges.

It is called a trench, which is the current aqueduct. In ancient times, flying canals were mostly made of wooden. It records that there was a "flying canal to divert water into the city" in the southwest of Chang'an of the Han Dynasty, which is the first aqueduct in my country recorded.

The two ends of the flying canal are connected to the channel. The water flow of the transport channel spans rivers, valleys, depressions and overhead sinks. They are generally used for irrigation and water transfer, and are also used for flood discharge, sand discharge, etc. Large aqueducts can also be navigated. The aqueducts are mainly made of materials such as stone masonry, concrete and reinforced concrete.

The earliest aqueduct in the world was born in the Middle East and West Asia. In 703 BC, the king of Assyrian king ordered the construction of a 483-kilometer-long aqueduct to divert water to the capital Nineveh. The aqueduct was built on a stone wall and crossed the valley of Zewen. The stone wall was 21 meters wide and nine meters high, and a total of more than two million stones were used. There were five small bridges under the aqueduct, allowing the stream to flow through.

Many cities in ancient Greece also had good aqueducts, but the ancient Romans were the most serious and regarded the water supply system as an important part of public health facilities.

The first water supply aqueduct in Rome was the Api Aqueduct built in 312 BC; the tenth and last one was the Alexandria Aqueduct built in 226 AD; the longest and most spectacular one was the Marcia Aqueduct built in 114 BC.

Under the existing conditions, if he wanted to build a tap water system, he had to use flying canals and water towers.

The water source of "tap water" in Chang'an still comes from Furong Pool: flying canals are set up from Furong Pool to each yard area, inject water into the water towers of each yard area, and then water inlet pipes are laid from each water tower to each household.

After Yin Qingfeng sketched according to his ideas, he realized that things were not as simple as he imagined.

If he had imagined, the entire sky above Chang'an would be covered with crisscrossing flying canals. He imagined this scene and felt that there was only one: Li Yuan and Li Shimin would not let him do this even if they were beaten to death.

Not to destroy the underground Feng Shui, but let the emperor drill from the flying canal when traveling. Is this a good thing?

So Yin Qingfeng had to give up this idea. He should honestly think about how to complete the tasks assigned by Li Shimin.

But the problem arises again: Yin Qingfeng doesn't want to become a "contractor", and someone else has to take the blame.

Although the status of industry and commerce was not as outrageous as it was in the early Tang Dynasty, he had no time.

A group of naughty kids had to watch and teach. Ma Zhou broke into the door from time to time and explained the arguments with him. Now Lu Cai has started learning and will come to him from time to time for advice.

After thinking about it, he might as well invite Xu Xiaode, who is newly married.
Chapter completed!