Zhang Zhaohua said so many words, only the last sentence shocked everyone to change color.

The ancestral tomb is the actual burial place of the great ancestor, great-grandfather, grandfather and grandfather of Emperor Taizu Gao, located in Sizhou City, this place is the southern port of the two banks of the Huai River and the North-South Grand Canal from the Huai River into the Bianhe River, if it is according to the method of Huang Chuze, a large number of diversion on the south bank of the Yellow River will lead to the direct threat of the ancestral tomb, and if the Yellow River takes the Bianbian into the Huai, the city of Sizhou will suffer a catastrophe.

"Then you say," said the people in Xishan, "what should we do if the Yellow River can't go south?"

"The Yellow River must go south, from Huai to the sea. Zhang Zhaohua sighed in her heart, this is because of the background of Caoyun at this time, and she has no way to change it for the time being: "But it must not be diverted, my method is to harness the water and attack the sand." ”

As soon as this word came out, no one could understand it, but Lin Fang was not ashamed to ask and asked her to explain very patiently. Zhang Zhaohua cleared his thoughts and said: "The method of relying on manpower to dredge the Yellow River is too labor-intensive. Because of such a big Yellow River, in this section of Cao County, the water depth is six or seven zhang, the shallow place is also three or four zhang, the river is one or two miles wide, and the narrow place is also one or two hundred zhang. I wonder if there are tens of millions of buckets of sediment, can we dig them up by manpower? Even if we can do it, if we don't build an embankment, the next time the flood arrives, there will be another breach and overflow, and the riverbed will soon be filled with sediment and silt.

Restraining water and attacking sand, this is the most essence of the concept of taming the river in the late Ming Dynasty, relying on the natural force of the Yellow River, borrowing water to brush the sand, the specific method is to stabilize the river channel through the embankment, relatively narrow the river cross-section, increase the flow rate, improve the ability of the water flow to carry sand, use the hydraulic brush deep river channel, artificially speed up the discharge rate, so that the sediment not only does not deposit, but also scours the bottom of the river, and deepens the river.

Before she could finish speaking, someone shook their heads.

"It's a good idea," Huang Chu said, "but how wide should the embankment be? ”

"Yes, the river water has a wet period, the dry period, the embankment is wide, the dry season does not play the role of restraining the water, can not attack the sand; it is narrow, the pressure during the flood period is too great, and the embankment is burst at every turn, how to solve it?" Lin Fang also shook her head.

Zhang Zhaohua picked up the pen and paper on the table, drew a river, and drew two straight lines on both sides of the river to represent the embankment: "Build a double embankment." ”

The embankment is a bundle of embankments built on the riverside, with the purpose of narrowing the river channel and binding the river to penetrate the riverbed. The remote embankment is built two or three miles away from the embankment, in order to prevent the flood from flooding after the river floodplain or the embankment is washed away. This method has been used by later generations since it was proposed by Pan Jitao, and even in Zhang Zhaohua's time, the embankment in the lower reaches of the Yellow River was this practice.

Pan Jitao's most admirable one is to store and clear the Yellow River, that is, to block the Hongze Lake embankment in the upper reaches of the Qingkou, build the Gaojiayan embankment, and store the water of the Huai River in the Hongze Lake, so that the clear water of the Huai River can be cleared and flow into the Yellow River, so as to achieve the purpose of scouring and clearing the mouth - but it is not applicable to now.

Because it was at the beginning of Wanli, the Yellow River broke Cui Town to the north, the Huai River broke to the east of Gaojiayan, the Qingkou at the intersection of the Huang, Huai and Yun was silted, and the Yellow River below the Qingkou was also seriously silted up, leaving only a ditch of water, and it was impossible to manually clear the mouth, Pan Jitao came up with such a bold method after field investigation, this genius method created Hongze Lake, that is, the Hongze Lake in later generations was actually a large-scale water conservancy hub artificially formed after Pan Jitao implemented the policy of storing Huai and brushing the yellow.

This method can not be implemented for the time being, but it proposes the strategy of "water storage" and "flood control", can be used, Pan Jitao built the flood reservoir reflects the prototype of modern artificial reservoirs, it has included the main components of modern artificial reservoirs at that time: reservoir area, water retaining buildings, water intakes, spillways, these can be built slowly.

Zhang Zhaohua laboriously recounted her proposal to set up remote embankments on both sides of the Yellow River and return the river to the trough, and among several officials, some nodded, some shook their heads, some were absent-minded, and two or three looked at the door from time to time, as if they were about to go out to eat when she finished speaking.

To Zhang Zhaohua's disappointment, Lin Fang, who was very patient, didn't seem to be very interested in her methods, and said: "Is there anyone in the world who can come up with a strange plan to restrain the water of the Yellow River? I think Madame Zun's idea is too naïve, and it is still not advisable! You still listen to the official's words, it is better to carve out a place in Xu Huai, let him wander and overflow, and just try your best to protect the luck." ”

These words were said to Yang Shiqi, which made Yang Shiqi's face blush, but he naturally would not follow the other officials to nod, but what made him curious was that how could a deep palace maid like the crown princess know so much about the situation in the Yellow River?

Zhang Zhaohua never thought that Lin Fang would be able to do it as long as the canal was unblocked, the Yellow River overflowed, and what was the point of flooding, in fact, she should also know that the new method of ruling the river has not been tried or practiced, and it sounds like a fantasy, which can only be imagined, so the officials can't believe it, and they can't take risks - at this time, the general rule that the officials who govern the river is Song Lian's method, which flows from north to south. But what has changed slightly is that the north bank cannot be passed, because the canal is not smooth like the Hongwu time. But it is possible to flow southward, as long as the current trend of the Yellow River, Heying and Vortex two waters enter the Huai, you can "kill the river potential" and discharge the flood.

And Lin Fang also said meaningfully, the Yellow River has many branches to drain down, even if there is more sediment deposits, it will not flood Sizhou, unless the small lakes around Sizhou rise - this is exactly the result of Zhang Zhaohua's desire to implement the storage and clearing of the Yellow River after the water and sand attack, and it is also the reason for the failure of Pan Ji's taming of the river.

To a certain extent, Lin Fang is actually right.

Zhang Zhaohua couldn't say a word, she turned her head and left the shed. There was a burst of laughter behind him, and Lin Fang laughed and said, "Lord Yang, your lady is very temperamental." ”

Zhang Zhaohua sat on the embankment and looked at the gentle river, I don't know how long it took to hear Yang Shiqi's voice, and he also sat on the embankment.

"What did you discuss?" Zhang Zhaohua asked calmly.

"Build an embankment," Yang Shiqi said: "On the north bank of the main stream of the Yellow River, from Lihua County, Changyuan, Dongming, Caozhou, and Cao County to the boundary of Yucheng County, build a long embankment, about 360 li, to block the river from going north. ”

Zhang Zhaohua's eyes lit up slightly, and said: "Taihang Dike - count him Lin Fang still has a little vision." ”

In fact, there is a levee that Yang Shiqi said just now, which is called the Taihang embankment, but in history, it was built by Bai Ang when he presided over the river during the Hongzhi period, and this embankment was very effective, and it did block the river from going north and maintain the stability of the canal.

"This embankment is not enough," Zhang Zhaohua said: "To the south of the embankment, it is necessary to build a 60-mile inner embankment from Yujiadian through Jinglongkou, Tongwaxiang, and Chenqiao to Xiaosong Bridge, and the two embankments at the front and back complement each other to block the river and become the two lines of defense on the north bank of the Yellow River." ”