Chapter Fifty-Five: Building Dams and Silt Fields

Wei Renshi chuckled and asked, “How did Secretary Liu know I came here specifically to see him?”

“The food at the courier station could never compare to the delicacies in the city’s taverns and restaurants. You left behind Fuchang and came here instead, so you must have another purpose.” Lin Sumian smiled and said, “From the moment you entered, your gaze was fixed on him, as if you recognized him. You also carefully observed how he spoke and conducted himself with others. Clearly, you came for him.”

“So both of you noticed?” Wei Renshi laughed. “He’s the future manager who will run my business in Luoyang.”

“But what about this damming and siltland…” Liu Yuxi pressed him.

Wei Renshi didn’t drink the water in his bowl, wary of parasites, and pushed it aside. He said, “That phrase needs to be split—one part is damming, the other is siltland.”

“Damming means building a dam. But this kind of dam is different from ordinary ones,” Wei Renshi explained to Liu Yuxi. “These dams don’t have to be built particularly high, but rather, are constructed in tiers, like steps. The location is not where ordinary dams are set, but rather within the overflow channels of rivers. Water flooding out descends step by step along the dams, lingering at each stage, allowing sediment in the water to settle. So, Secretary Liu, you may select narrow points in the small gullies and streams formed by floodwaters in Weinan, and from each side of the hills, build dams as high as the hilltops, completely blocking the gully. Then, construct smaller dams in tiers downstream. When floods come, the water will again pour into these channels, and you simply allow it to accumulate within the gullies.”

“And after that?” Liu Yuxi asked eagerly.

Wei Renshi replied, “The second step is creating siltland. As water accumulates, locals can use it for storage. Draining the water takes more than a day or two, so when drought strikes, the water stored in these small dams can be used by the people. Built in succession and supported by the original large dam, these dams can intercept and hold back water in layers. When floods hit, they serve as effective buffers, holding back the water above and protecting the land below, preventing the flood from carrying silt downstream and causing damage.”

Liu Yuxi’s face lit up with delight as he grasped the full import of the solution.

“Excellent! That’s precisely the effect!” Liu Yuxi praised him. “You, Master Wei, are truly a man of great talent to have devised such a method!”

Wei Renshi smiled. “That’s not all. With the gullies blocked by tiers of dams, river water accumulates in stages. The silt settles, gradually turning the area into flat land suitable for sowing autumn wheat. The land formed by river silt is all high ground—fertile, drought and flood resistant, and exceptionally high yielding.”

He continued, “Building dams along the Weigou channels can store water and retain silt; once the silt is cleaned out, it can be used as fertilizer, benefitting both agriculture and water management. The usual method of building large reservoirs to conserve water isn’t suitable for the Yellow River, as it carries too much silt, causing the reservoirs’ capacity to shrink too quickly. But if we disperse the effort into the gullies and ditches, it’s like having countless small reservoirs, enjoying the benefits without the drawbacks, and the silt can also be used to create fertile farmland. Secretary Liu, why not give it a try?”

Liu Yuxi, his eyes glimmering with excitement, had already begun to imagine countless new possibilities.

After a long while, Liu Yuxi sighed, looked at Wei Renshi, and said with a smile, “I have reached thirty, and have walked the world for almost twenty years, yet today I find myself wholeheartedly convinced by a young man not yet of age.”

Seeing Liu Yuxi’s sincere admiration, Wei Renshi felt a tinge of guilt. This method of damming and creating silt fields was truly the collective wisdom of the laborers from the Loess Plateau—a technique practiced since the Ming Dynasty to control drought, flood, and soil erosion, and it aligned perfectly with the later national policies of integrated watershed management.

Beside him, Lin Sumian let out a deep sigh. “That is what I call great skill. It seems what I have dabbled in all these years were but small tricks.”

Wei Renshi looked at him, puzzled.

Lin Sumian’s expression was slightly somber. “My family is originally from Putian in Fuzhou, a well-established clan. I, Lin Cen, am a concubine’s son, but I was the first to pass the exams as a tribute student. The family spared no effort to support my studies, and I have always hoped to benefit the people. But since childhood I was also fascinated by ingenious devices, and my family, considering such skills frivolous, often suppressed this interest. Later, I went to the capital and saw that scholars from all over the realm were either pedantic in youth or corrupt in old age, content only with empty discussions of poetry. Most of the officials I approached were idle and did nothing. Disheartened, I devoted myself to these so-called ‘ingenious devices’—which, to my mind, could truly help people, far more than any poetry or essays. Take Master Wei’s plow: as soon as it was built, countless people benefited at once. Can writing poetry in a study accomplish that? My clan was greatly disappointed in me, so they focused on my brothers instead and sent me to Weinan to manage the family business there.”

Wei Renshi had not realized that this seemingly forthright man harbored such feelings, and for a moment, he was silent. To be sent from Putian in Fuzhou all the way to Weinan—that was indeed far.

Lin Sumian went on, “Coming to Changgu this time has truly not been in vain! The plow you made, Master Wei, benefits countless people; your irrigation device does the same. Now you propose this dam-and-siltland plan, which not only controls flood and drought but also creates abundant new farmland. When I first saw your plow, I thought you were another person, like myself, obsessed with so-called ‘ingenious devices,’ and I wanted to meet you because of the cleverness of your design. But after hearing your damming and siltland plan, which brings blessings to the people and peace to the land, I realize your vision and ability far surpass mine. My own obsessions, I now see, are but petty skills; what you pursue, Master Wei, are the great arts that benefit the world!”

“I am merely standing on the shoulders of many great predecessors, and so I know some things that others do not at present,” Wei Renshi shook his head, murmuring something the two could not understand. After a pause, he smiled, “If you enjoy these ‘ingenious devices,’ Brother Lin, we can certainly exchange ideas more often in the future.”

Lin Sumian was taken aback, then overjoyed. He quickly raised his hand in salute. “Thank you, Brother Wei! Your generosity is something I will always remember!”

Liu Yuxi, standing nearby, laughed. “Master Wei, you possess such breadth and magnanimity; you are destined for greatness! When I return to Weinan, I will immediately begin experimenting with this dam-and-siltland method. If successful, it could benefit all of Guanzhong, bringing prosperity to countless people and adding vast new lands to our Tang Dynasty in Guanzhong!”

At that moment, however, Wei Renshi had already turned away, once again watching the performance of Old Sun’s nephew.

He had shared the dam-and-siltland method with Liu Yuxi simply because he liked the man. Who in later generations hadn’t learned a few of his poems? “Beside the wrecked boat, a thousand sails pass by; before the dying tree, ten thousand trees bloom with spring”—what breadth of mind, what resilience and hope!

Although Liu Yuxi had not yet written that poem, it did nothing to diminish Wei Renshi’s admiration for him as someone from a later age. Since they had met and become acquainted, he thought, why not help him if he could?

As for whether or how Liu Yuxi would carry out the plan, that was not something he could concern himself with—nor did he have the means, for now, to worry about such grand matters.

By now, the crowd had thinned, and Old Sun’s nephew was resting, sitting in a corner.

“You there, young man, come here a moment,” Wei Renshi called out to him.