After passing the Xuanmen Pass and continuing westward, Liu Xiang was unable to say a word at the ruins of Gongxian, Yanshi, and Luoyang, and the whole army was filled with indignation.
The Qingqi detachment searched this way, but did not find any large groups of bandits. They took care of the scattered thieves themselves, and the army only needed to concentrate on their journey.
When passing through Luoyang, Liu Xiang took Cao Cao to inspect the breached embankment. After four months of repairs, the original breach had been repaired, and more than ten thousand hard laborers were strengthening the embankments in other sections of the river.
Cao Cao was surprised. He wasted manpower and material resources to repair a river embankment that was not his territory. He didn't know how to evaluate it. Was he stupid? Or was he confident about going south? He didn't want to understand.
"Mengde, I am going to re-plan the river embankment and use the method of widening the river and strengthening the embankment to prevent floods."
“What is wide river embankment consolidation?”
"Build a stronger embankment on the outside of the existing river embankment and extend it ten miles back, and build a breakwater on the slope facing the water to prevent flooding. In this way, we can effectively prevent floods and wait until the floods pass.
, ordered people to clean up the river channel between the two embankments. The silt can fertilize the fields, the sand and gravel can be used for construction, and it can also slow down siltation."
Liu Xiangchang talked about his philosophy of regulating the Yellow River and couldn't help but muttered: "It's a pity that we can't build a sand control project in the middle reaches."
The construction of a thousand-mile dike was extremely costly and the consumption of manpower and material resources made Cao Cao's scalp numb. However, his courage to manage the Yellow River also made him admire him greatly.
While others are thinking about how to expand their territory and strengthen their power, this man is already thinking about how to regulate the Yellow River.
Such a big heart, able to make judgments!
Hearing the word sand regulation project, he was confused: "Sand regulation? How to regulate sand? Take the sand out of the water?"
Everyone knows that the Yellow River carries sediment, but the concept of sand regulation did not exist in the Han Dynasty. Cao Cao had never delved into water control. He couldn't figure out what sand regulation meant even if he tried hard.
The matter of sediment regulation is a very scientific matter, something too profound for Liu Xiang to understand, but he knows that the Sanmenxia Reservoir and Xiaolangdi Project can effectively reduce the sedimentation of downstream rivers. This kind of thing is to copy the questionnaire according to the answers.
, he still knows.
"Building a dam in Shaanxi County to form a reservoir will allow part of the sediment in the river to be deposited, and there will be less siltation downstream. However, if the Sanmenxia river course is raised too high, the Wei River will flow backwards, easily causing Sanfu flooding.
.
Therefore, another water dam must be built downstream to form a new reservoir. The two reservoirs are linked to block water and sediment, and reduce the sediment content of the river water. When there is too much sedimentation, artificial floods are created to flush out sediment and discharge sand.
.”
The reason is very simple, but the difficulty of the project is too high. How can it be built with the construction technology of the Han Dynasty? It is too difficult!
The Sanmenxia River section is a natural place where water collects and washes away sand. However, the flow rate of the downstream section is slow, so the sediment accumulation in the Luoyang section is particularly serious. If only the river bank is used to restrain it, an above-ground river will inevitably form. This is a natural problem of the Yellow River.
Floods must be artificially created to help remove sand and silt there.
He understands the truth, but technology cannot keep up.
Liu Xiang was very troubled.
Cao Cao was stunned, are you speaking human words? He knows about dams, and he also understands about blocking rivers, but how to block the Yellow River? Is that possible with human power? And artificially creating floods to impact river siltation, you are going crazy.
ah!
He didn't know how to persuade, or whether he should persuade, so he simply kept silent.
Liu Xiang rubbed his temples. There was no use worrying about it. Write it down first and wait until the technology is accumulated to that point. Even if you can't reach it in your lifetime, you can still write it down to serve as a reference for future generations.
No need to worry now.
Thinking of this, he turned around and said: "Let's talk about the sand control project later. First, use the method of widening the river and strengthening embankments to control the river. When Luoyang was rebuilt, the farmland ten miles on both sides of the river were all designated as official land for the purpose of building embankments.
We can start construction directly when the time comes to save trouble. Jizhou and Yanzhou downstream are already making adjustments."
"The general is still thoughtful." Cao Cao flattered him.
"Let's go, the vanguard has passed Gucheng and is about to enter Beikiao Road. Let's catch up quickly."
The land passage from Luoyang to Guanzhong must pass through the mountainous area of Mount Wei between the Yellow River and Luoshui River. There is a natural danger in the mountains called Hangu Pass, so this route is called the Weihan Passage.
The Xiaohan Road is centered on Sanmenxia. There is only one channel to the west of Sanmenxia and two channels to the east. The south side goes through the Luoshui River Valley and is called the South Xiaodao Road. The north side is naturally the North Xiaodao Road.
The 60,000-strong army had the guard camp led by Huang Zhong as the front, 40,000 troops led by Xia Houyuan, Cao Ren, Cai Mao, and Zhang Xun as the middle army, and the rest of the troops as the rear. The three groups of troops marched in a meandering way, spreading for more than 20 miles.
Pass through Gucheng and proceed towards Hangu Pass.
Hangu Pass in the Han Dynasty and Hangu Pass in the Qin Dynasty are not the same place. Although they are both in the mountainous area of Xiaoshan Mountain, they are three hundred miles apart from east to west.
Hanhan Valley Pass is located at the east entrance of the Xiaoshan Mountains, and Qinhan Valley Pass is located at Sangchoyuan to the west of Sanmenxia. Because during the Han Dynasty, the Yellow River was cut downwards, exposing the river beach to the north of Sangchouyuan, and it can be accessed directly from the river beach.
, so Qinhangu Pass lost its strategic value and was naturally abandoned.
During the reign of Emperor Wu, the site was re-selected and a new Hangu Pass was built.
Now, Hanhangu Pass was also destroyed by Dong Zhuo. The city was in ruins and no one was garrisoned for a long time.
After passing Han Valley, we passed by the ruins of Xin'an County and continued on to Yima, the place where Xiang Yu, the overlord of Chu, killed 200,000 Qin soldiers.
When passing by here, Lao Cao was inspired and kept talking for a long time, but unfortunately, he couldn't compose a poem.
Tsk, where is the great poet we promised?
Liu Xiang was very disappointed.
Continuing westward, we arrived at Mianchi County, and there was no one there. It wasn't that Dong Zhuo burned it down when he moved the people, but that Hu Zhen had stationed troops here before, and the people were robbed too hard. The people either died or ran away, and they couldn't survive.
Then the army couldn't get supplies and withdrew.
The same is true for Shaanxi County to the west of Mianchi.
All abandoned.
Liangzhou soldiers are really ruthless.
There is a ferry in Shaanxi County that leads to Hanoi County on the north bank, but the army did not cross the Yellow River north, but continued to march westward and entered Shaanxi.
Shaanxi is a place name that existed in the Zhou Dynasty. Due to the erosion of running water, the highlands in Shaanxi County are steep on all sides and flat in the middle. They are called plateaus. One of them is called Shaanxi plateau. During the period of King Cheng of Zhou Dynasty, Zhou Gong and Zhao Gong assisted in the government, and Shaanxi plateau was called Shaanxi plateau.
The east side is called Shaandong, governed by Duke Zhou, and the west side is called Shaanxi, governed by Duke Zhao. This is the origin of Shaanxi.
Liu Xiang was able to lead his army along the ancient Xiaohan Road at a leisurely pace of forty miles per day because he could get supplies from the other side at any time. However, Li Jue, Guo Si and others disappeared after fleeing and neither gathered troops nor horses.
, and did not win over the Qiang and Di. Anyway, they did not see any movement of their counterattack on Chang'an.
That's weird. He couldn't really run away incognito, right? What was this old bastard Jia Xu thinking?
Liu Xiang could no longer control where things would develop. Should he directly attack Chang'an and depose the emperor to establish himself on his own?
Actually, it's not impossible.
In the past, he was afraid of the scholar group headed by Yuan Shao, Yuan Shu, Cao Cao and others. He did not dare to touch the emperor's order to the princes.
Now, there is really nothing to worry about. I want to use the power of Li Jue and Guo Si to attack Chang'an, just to save some energy and not to ruin my reputation.
After all, regicide, usurping the throne, etc., do not sound good and will hinder the win-win of people's hearts.
Liu Xiang, who walked out of Xiaohan Road and came to Taolinsai, frowned and looked at the defenders on the wall, wondering what to do next.
He believed that Jia Xu had a plan, but he hadn't seen it yet.