Great Song Dynasty Writer

Chapter 127 "Water Window"

Lu Beigu's idea was not complicated.

When he went to Ganzhou, Jiangxi Province for a meeting in modern times, he visited the Fushougou Museum there.

The so-called Fushou Ditch refers to a set of urban flood control and drainage water conservancy projects built during the Xining period of the Northern Song Dynasty. It was presided over by Liu Yi, the local prefect and water conservancy expert who served as the director of water management several times. It was named after the two drainage main systems that were built, which resembled the ancient seal script characters "Fu" (福, meaning fortune) and "Shou" (寿, meaning longevity). The whole project consists of three parts: a ditch that is more than 20 miles long, nearly 100 ponds in the city that regulate the capacity of rainwater, and 12 water gates to prevent the backflow of river water.

This water conservancy project has been in use from the Northern Song Dynasty to the present day. It has not only saved Ganzhou, which is surrounded by water on three sides, from urban flooding, but also withstood the test of that great flood.

The most exquisite part of Fushougou is not the drainage ditches and ponds within the city, which anyone can dig, but the "water windows".

Liu Yi's invention, the "water window," was a simple one-way wooden gate designed at the drainage outlet. It used the gravity of the water flow inside the city to open the drainage channel. When the river water level rose higher than that inside the city, the water pressure automatically closed the gate to prevent backflow.

It belongs to the category of water conservancy equipment with an extremely ingenious design but a fairly simple principle.

Most importantly, the construction of the water windows was entirely in line with the craftsmanship of that era, without any technical difficulties, and it has stood the test of time in Ganzhou, a city with a similar topography to Luzhou.

Therefore, Lu Beigu was confident that he could use this to initially alleviate the city's flooding.

We must first solve the flooding problem so that people are not left homeless before we can talk about anything else.

After all, once people lose their fixed abode and stay in the rain for a long time, they will soon fall ill in large numbers due to the cold.

"This thing alone can ensure that the Tuojiang River water won't flow back in?"

Li Pan examined the "water window" structure diagram drawn by Lu Beigu with a brush on the paper, somewhat doubtful.

Liu Yi was a Jinshi (successful candidate in the highest imperial examination) during the Qingli era. At that time, he should still be serving as the magistrate of Qushan County. Water windows certainly had not yet come into existence. However, Lu Beigu did not intend to steal other people's inventions, so he simply told him.

"Definitely!"

Lu Beigu's voice was resolute and exceptionally clear in the noisy government office.

"This device is called a 'water window,' invented by Liu Yi, a Jinshi (successful candidate in the highest imperial examination) during the Qingli era. I learned about it by chance. Its ingenuity lies in the principle of 'the window opens when the water recedes and closes when the water rises.' The water accumulated inside the city has potential energy, which can push the sluice gate to open and discharge the water into the Tuojiang River. Once the water level of the Tuojiang River rises and is higher than that inside the city, the pressure of the river water itself will force the sluice gate to close tightly, preventing any backflow! This is using water to control water, leveraging the momentum of the water!"

He pointed to the seemingly simple wooden sluice gate structure on the blueprint: "The materials only require hardwood, iron axles, and stone troughs. The craftsmanship is also not difficult; the carpenters and masons in the city can easily handle it. Just select a few key locations at each water gate and modify them, and the results will be immediate!"

Li Pan's gaze swept back and forth between the blueprints and Lu Beigu's resolute face.

He didn't care who invented it, nor how Lu Beigu found out. As a pragmatist, Li Pan was now considering the pros and cons of this matter for him, and only then for Luchuan City.

After thinking for a moment, Li Pan said, "Of course I believe you, but this matter is of great importance, concerning the safety of the entire city, so we need Prefect Liu's approval first."

Li Pan then led him to the room of Liu Yong, the prefect of Luzhou, which was not far away.

Liu Yong was worried about the flooding in the city, the high grain prices, and the surging river water outside the city.

Hearing that Lu Beigu, whom he had met once before, had come to offer advice, he did not refuse.

After listening to the details, Liu Yong hesitated.

The rain outside the window was like a waterfall, and the disaster situation inside the city was urgent.

Inside and outside the prefectural government office, colleagues were in a state of panic, and their solutions were limited to raising the dikes, organizing manpower to bail water, and praying for clear skies—all merely treating the symptoms, not the root cause. This "water window" method carried the risk of being unknown, but if it truly proved successful, it would be an excellent remedy for the immediate crisis!

Seeing the prefect hesitate, Lu Beigu said, "Now that the principle is clear, the most urgent task is to order the craftsmen to make a small sample according to the design. We'll know the result after one test! I am willing to personally supervise the construction!"

"it is good!"

Liu Yong truly lived up to his reputation as an official who dared to personally venture deep into the mountains of southern Sichuan to persuade the Liao people to surrender; in times of crisis, he indeed displayed considerable courage and decisiveness.

He slammed his hand on the table, causing the documents on it to jump.

"Lu Beigu, I'm entrusting you with the task of producing the prototype! I will immediately issue an order to allocate the necessary craftsmen and materials to you! Liu San, the clerk in the prefectural government, is familiar with the crafts and livelihoods in the city; he will be at your disposal!"

He picked up his pen and wrote rapidly, the ink dripping: "Remember, first make a small sample. Choose a not-so-important drainage ditch in the city to test it. Be very careful! If the sample is successful, report to me immediately, and then we can promote it further!"

Lu Beigu felt relieved and solemnly accepted the order: "This student obeys!"

"Go quickly!" Liu Yong waved his hand, his gaze once again falling on the mountain of official documents, the worry between his brows still lingering. "I hope your 'water window' can truly solve my predicament in Luchuan."

Lu Beigu said no more, bowed deeply, turned around and strode out of the government office.

Li Pan led him to the clerk Liu San. After hearing the prefect's order and the judge's instructions, Liu San did not dare to be negligent and simply said, "I will do as you command, Scholar Lu."

"Liu the clerk, there's no time to lose!"

Lu Beigu spread the blueprints out under the eaves to make sure they wouldn't get wet in the rain.

Looking at the peculiar gate structure on the blueprint, Liu San's surprise deepened; it seemed that the students from this state really knew something about it.

"Immediately summon three of the city's best carpenters and stonemasons, and prepare hardwood, iron, chisels, ropes, and other materials. We need to find a place with a drainage ditch that is relatively secluded, so that even if the experiment fails, the impact will be minimal! If the experiment succeeds, then we can build behind the water gate."

"There's an old ditch at the foot of the north city wall that leads to a small puddle. It usually only drains rainwater and sewage. The terrain is high enough that it's far enough away from the Tuo River and the Yangtze River that it won't overflow. It might be worth a try! The craftsmen and materials will arrive within half an hour!"

"Alright! Thank you, Clerk Liu! I'll go inspect that ditch first!"

Lu Beigu tightened his raincoat and stepped into the torrential rain again without hesitation.

On his way to the north city wall, he heard a woman holding a child, hiding under a high porch, murmuring to the crying baby in her arms, "My child, just bear with it a little longer."

The voice was so hollow it was heartbreaking.

Lu Beigu gritted his teeth, quickened his pace, and kept recalling the details of the water window in his mind to ensure that his replica would be flawless.

He had not only seen the physical reconstruction of the water window in the museum, but he had also studied the reconstructed water window in detail. With his memory, he was certain that he could perfectly replicate it!

Once inside the north city wall, he saw the old ditch, filled with rainwater and almost level with the road surface.

The murky water was slowly flowing out of the city through a narrow, moss-covered brick culvert.

At the exit of the culvert, one can vaguely see that the low-lying area outside the city has long been a swamp.

(End of this chapter)