Rebirth of the eldest daughter

Chapter 1186 Using the flood itself to remove sediment? Is it possible?

Meng Ziang nodded: "That's right. The so-called source is the root cause of floods. One is heavy rain, and the other is the breach of river defenses and the bursting of embankments."

"We can't control the heavy rain, but we can intervene in the river course. In the past few days, I have been thinking whether we can completely solve the problem if we just let the river return to its original course."

"The answer is no. The carrying capacity of these barrier lakes is too large and there is still a risk of their banks bursting. Therefore, we must return the rivers to their original channels and reduce the burden on these barrier lakes."

"As long as our timing and sequence are correct, we can achieve the effect of killing two birds with one stone - while recirculating the river and reducing the risk of the barrier lake completely bursting, we can also use the flood itself to remove the silt deposited in the river."

Although Bai Mingwei is not as proficient in water conservancy as Meng Ziang, she has also dabbled in it. During this period, she used all available time to supplement a lot of water conservancy knowledge.

When Meng Ziang said this, she understood: "What Mr. Meng said is reasonable, and this is also a very important aspect."

"If we can use floods to remove the silt deposited in the rivers ourselves, we can save a lot of manpower. This will play a vital role in helping people recover as soon as possible after the disaster."

"But I can understand the return of rivers and the release of floods from barrier lakes, but I don't understand the strategy of using the flood itself to desilt. May I ask, sir, how exactly should this be done?"

Flood desilting is really new.

Although some people have proposed such a theory in ancient ancient books and classics in the past, there has never been any successful practice.

When it comes to flood discharge and dredging, everyone will choose traditional methods.

When Meng Ziang saw that Bai Mingwei didn't look at him strangely, he instantly felt like he had found a soulmate.

He seemed particularly excited and talked endlessly:

"Imagine that the diverted river returns to its original channel, and then the large amount of floodwater collected in more than a dozen barrier lakes is released in a reasonable and effective way."

"In this way, the water that fills the north of the river will recede little by little, and eventually flow along the river into the sea."

"The silt and sediment that blocked the river due to flooding were also removed smoothly. From then on, the river was smooth, and the north of the Yangtze River was no longer a flood-filled country."

Speaking of this, Meng Ziang paused and observed Bai Mingwei's expression.

Seeing that Bai Mingwei had no doubts, he continued:

"At this time, we are going back to the issue of dredging the barrier lake to discharge floods. Next, I will demonstrate to the general what the operating principle is."

"It's just that this approach is unprecedented. I have not seen any successful precedent recorded in any book. I am not sure whether it is definitely feasible."

Bai Ming said slightly: "Sir, I built a small dam here with stones a long time ago just to verify whether this is feasible. We can roughly estimate it after trying it a few times."

Meng Ziang was startled when he heard this, but soon returned to normal.

He explained slowly: "General, look, a small dam has been built up in the stream, blocking the flow of the stream, and a small pool is formed upstream of the small dam."

"If this situation is placed on a large river, what is formed upstream of the dam is a lake, which is what we often call a barrier lake."

Bai Ming nodded slightly: "I understand what you mean, sir. You are using this stream to simulate the situation of Lingjiang River."

Hearing this, Meng Ziang nodded: "That's exactly it."

Immediately afterwards, he pulled up the torch and approached the small embankment, motioning to Bai Mingwei to take a closer look. "General, look. After the barrier lake was formed, the flow rate of the upstream water dropped sharply or became stagnant."

As he spoke, Meng Ziang threw a few handfuls of sand into the small pool.

He continued: "When flash floods carry a huge amount of sediment into the barrier lake, the sediment will slowly accumulate and raise the water level."

"But as long as the dam is stable, the barrier lake will gradually cut off the water supply downstream, causing the water potential downstream of the barrier lake to slow down, the flow rate to decrease, and the water level to decrease."

Bai Mingwei heard the words and nodded slowly: "I understand what sir said."

Meng Ziang was silent, and then said: "But what I want to say next, I'm not sure whether I can explain it clearly."

Bai Mingwei brought another torch and nodded to Meng Ziang: "Sir, just tell me. If you don't understand, I will ask you."

Meng Ziang pointed to the upstream and downstream of the small dam and continued to explain:

"General, please see, at this time, the water level upstream of the barrier lake is higher than the water level downstream, forming a water head. At this water head, it will raise the river surface downstream, eventually creating backwater."

"The backwater here means that when the huge current rushes down from the embankment, it is blocked and cannot flow downstream smoothly for a while. If it is released smoothly, it will flow back toward the embankment or both sides."

"When the backflow becomes large and the downstream is still unable to discharge smoothly, the water level in the downstream section of the river will rise, and the water level will rise significantly, causing the width of the river to increase and overflow to both banks."

"The backflow slows down the flow rate of the downstream river, and the sedimentation rate of the entrained sediment will also increase. The accumulation of more sediment will raise the height of the downstream river bed."

"When the continuously flowing water passes over these sediments, new sediments are continuously produced. Eventually, the river channel is silted up, and the water spreads to the river bank..."

Hearing this, Bai Ming suddenly realized: "Isn't what the gentleman said exactly the current situation in Jiangbei?"

Meng Ziang nodded: "What I just talked about is the process of the formation of floods in most areas of Jiangbei."

"General, if you think about it, are the areas with the most serious floods related to these dozen barrier lakes?"

Bai Mingwei carefully recalled the hydrographic map of Jiangbei and the latest information sent by the secret guards.

Finally, she nodded: "What Mr. said is not unreasonable."

Meng Ziang's eyes were burning, as if he had seen the flood problem in Jiangbei being resolved.

He opened his mouth and revealed the key point of this entire initiative:

"At this time, if the upstream barrier lake suddenly bursts, huge floods will wash away the sediment deposited downstream."

"As long as the amount of water reaches a certain degree, it can produce a huge impact and wash away the accumulated sediment."

Bai Mingwei heard the words, was silent for a moment, and then asked him: "Sir, do you mean to destroy these dams?"

(End of this chapter)