Chapter 627: A Thousand-Li Dike

As the Commandant of Water Resources upon whom the Son of Heaven had placed great hopes, Du Shi was in truth more skilled at harnessing water than at controlling floods.

To live up to the Emperor's weighty trust, he had spent the past several years poring over books on flood control — works like the ancient "Yu Gong Map," the "Classic of Mountains and Seas" compiled by Liu Xin, and the "Records of the Grand Historian: Treatise on Rivers and Canals," which comprehensively summarized canal and dike projects from high antiquity down to the reign of Emperor Wu of Han. Diwu Lun had also opened the Tianlu Pavilion to him, letting Du Shi search freely for useful materials.

In the "Classic of Mountains and Seas," Du Shi had come across a story: in high antiquity, when floodwaters surged to the heavens, Gun stole the Lord of Heaven's self-renewing soil to block the floods and was executed for it. Gun's posthumous son, Yu the Great, upon reaching adulthood, took up his father's work, continuing the struggle against the overflowing great river — and he too made use of the self-renewing soil.

At the time, Du Shi had wondered: just what kind of divine substance was this self-renewing soil? And in another book of vast learning, the "Huainanzi," he found his answer.

It was said that this self-renewing soil, when built into dikes, could grow of its own accord with the rising waters, inexhaustibly and without limit — and thus it could block the floods.

Du Shi felt both longing and regret. The nightmare of the great flood had descended once more; the Yellow River had run wild across the realm for over twenty years, but the self-renewing soil had long since vanished into the mists of high antiquity. No one could clearly say where it came from or where it had gone, let alone put it to use.

Diwu Lun, however, held an entirely different view. He had once said to Du Shi: "Though the self-renewing soil of old cannot be found, let us then bring our wits and wisdom to bear and create the self-renewing soil of our own age!"

He meant what he said, and he actually managed to concoct a "self-renewing soil." This substance was made by mixing and firing clam-lime — plentiful along the seashore — with clay; limestone could also be used. When blended with the right amount of water, it became a rather soft slurry. Left to dry in the sun and wind, the slurry's strength increased dramatically by the hour, losing its plasticity and turning into a dense solid that could not flow. When Du Shi touched it, it felt like pressing against hard, unyielding stone.

And when mixed with sand and gravel, this "self-renewing soil" could bind them tightly together into a solid whole. The entire process could be described by a term Diwu Lun had coined —

"Concretion."

Exactly — concretion! This utterly unremarkable-looking gray mortar could, in a short time, form walls with a hardness rivaling stone. Diwu Lun had directly turned his soon-to-rise "Eastern Capital Traveling Palace" into a testing ground. He had artisans collect clam shells, limestone, and the like, fire them on site, and then mix them with clay in varying proportions to concoct "self-renewing soils" for different functions.

The Emperor said to Du Shi with a cheerful laugh, "I expect that among these, quite a few will prove useful in controlling the floods."

Useful? That was putting it far too mildly!

Greatly stirred, Du Shi said to Diwu Lun: "Your Majesty, in past flood control efforts — such as the blocking of the breach at Huzi Mouth in the second year of Yuanfeng under Emperor Wu of Han — bundles of firewood and bamboo baskets woven from Qiyuan bamboo were filled with stones and used to plug the gap. The two 'Songs of Huzi' may be majestic in spirit, but bamboo and wood rot easily. In as little as half a year, or at most a few years, they inevitably decay, and once the stones lose their binding, the waters scatter them and the breach is imperiled once more."

"And in ancient times, when building dikes along the great river, the earliest method was rammed-earth embankments. Yet no matter how solidly rammed, earthen walls soaked year after year would still soften and crumble. By the Han dynasty, stone dikes began to be built. I have walked them myself — following the old course of the great river, from Henei north to Liyang, east to Pinggang in Dong Commandery, northeast to Jinbei in Dong Commandery, and northwest to Zhaoyang in Wei Commandery — all are stone dikes. Yet stone dikes are difficult to stack tightly; they have many gaps. Moreover, with centuries of silt buildup from the great river, the riverbed has risen higher and higher — and that is precisely why the great river so often breaches."

This "self-renewing soil" had a plasticity comparable to rammed earth, yet its hardness and imperviousness to water could rival solid rock. Combining the strengths of both, Diwu Lun had without doubt given Du Shi a supremely powerful tool!

This instantly filled Du Shi, who still harbored misgivings in his heart, with confidence. The next day, having stayed up all night, he reported an even more detailed river-control plan to Diwu Lun.

"In the time of Emperor Cheng of Han, a man named Jia Rang proposed three strategies — upper, middle, and lower — for controlling the river."

Du Shi said: "His lower strategy was to repair the old dikes along the great river's winding course, raising the low sections and doubling the thin ones — minor mending and patching. But this strategy entailed endless labor and expense, with disasters striking repeatedly, and could only maintain peace for a few decades. Sure enough, twenty years later, the great river breached."

"His middle strategy was to dig many diversion canals, slightly dividing the water's force — enough to preserve stability for at least a hundred years."

"And his upper strategy was to abandon the low-lying coastal areas of Ji Province and Qing Province, relocate a million people, and deliberately breach the river, letting the great river find a new course to the sea."

On the face of it, this upper strategy sounded like a colossal joke, no different from lying down to drown. But one had to consider the reality at the end of the Han: after a thousand years of silt accumulation, the Yellow River had become an elevated river, held back entirely by the dikes along its banks. In truth, the water's surface had long since risen higher than the houses. It hung over people's heads like a sword of Damocles. Even if the lower strategy patched things up, even if the middle strategy steered away from harm and toward benefit, the day of catastrophe would still come, sooner or later!

"Thus Jia Rang held that, although this measure would ruin walled cities, fields, dwellings, and graves by the tens of thousands, it would be enough to resolve the peril of the suspended river. Once the river was settled and the people secure, there would be no calamity for a thousand years."

Du Shi said with deep sorrow: "Now the great river has been breached for over twenty years. Its waters can no longer return to their old course; instead, they have found a new path of their own through the lowlands. Though still unstable, submerging ten thousand mu of good farmland and countless walled cities, and causing a million souls to flee or perish, it has indeed achieved the effect of Jia Rang's upper strategy."

At the very least, that insoluble "elevated river" was finally gone. This was truly the "upper strategy" bought at the most ruinous cost — but it also gave Diwu Lun the chance to start everything anew!

"All things have a beginning. In my judgment, river control must start with the Bian Canal."

Du Shi presented a sketch he had drawn. Diwu Lun bade him come forward, and ruler and minister bent together over a low table.

This Bian Canal was in fact the upper reach of the Honggou, diverting the Yellow River's waters southeastward and ultimately flowing into the Huai River system. Yet since Han times, the Yellow River's floods had frequently invaded its tributaries, with the Honggou and the Ji River suffering the most. When the court still maintained order, it could repair the dikes and manage things, but ever since the chaos of Wang Mang's Xin dynasty, the canals had become motherless children. Turbid waters surged in, and downstream from the Yingyang canal mouth, a vast expanse of marshland had formed.

Diwu Lun nodded. "The Honggou is close to the Central Capital, Luoyang. The dozen or so counties nearby produce abundant grain and cannot be neglected. It also bears on military farms and water transport north of the Huai, so it must be given priority."

To make the Yellow River obediently stay in its new course, they not only had to guard against it invading the Ji River but also had to strangle in the cradle any possibility of it using the Honggou to invade the Huai. Though Diwu Lun was at war with Liu Xiu, he had no wish to use water as a weapon.

Du Shi reported that the greatest difficulty in managing the Honggou was the Yingyang canal mouth. This was the diversion point, and it required a sluice gate to control the volume of water entering the Bian Canal.

Using the bamboo slips on the table as an analogy, he explained: stone would be added atop an earthen dam, linking it to the Yellow River's dikes, leaving only an opening a few zhang wide. Thick planks would be slotted in to serve as a water gate. When the Yellow River ran high, the gate would be opened; when the water was low, it would be closed — thus controlling the flow entering the Honggou.

"And in building the dikes and sluice gates at this canal mouth, the self-renewing soil will be of immense use!"

Du Shi envisioned with excitement: since the self-renewing soil was so highly plastic, it could not only reinforce dikes at critical points but also be used to make "concretion sluice gates" to replace the wooden gates that rotted so easily!

"If the Yingyang canal mouth of the Honggou can be properly repaired, then for a thousand li downstream, every canal mouth can employ this method. By slightly dividing the water's force, the people can irrigate their fields. This will leach out the salt and damp, increase silt and fertility, allow the planting of wheat and rice, and moreover bring the convenience of transport barges and boats. Thus a harmful river becomes a beneficial one — enriching the state, securing the people, promoting gain, and eliminating harm."

Of course, this was only a mid-scale project, requiring tens of thousands of laborers — something the various provinces and commanderies could still bear. The true test, however, was a grand project that made even Diwu Lun's heart tremble when he heard of it!

"The most urgent matter at present is still to stabilize the great river's new course. Therefore, the river-spanning dikes must be rebuilt using the current-blocking method."

Taking up a brush, Du Shi drew a line on the map: from Yingyang in the Sili region all the way to the Qiancheng estuary in Qing Province, where they now stood — long dikes must be built to hold back the waters.

Diwu Lun narrowed his eyes and studied this line several times over. He asked Du Shi, "How many li in all?"

"By rough estimate, over a thousand li!"

That meant a great wall over four hundred kilometers long — and not just one, but two of them!

They must stand flanking the river, like defenses against raiders, penning in this giant dragon that loved to twist and thrash! Only then would the subsequent work — dredging the channel, cutting bends and straightening curves, chiseling high ground and filling low — to make the river flow more smoothly, only then would all that become possible.

It would be a project of incomparable grandeur. The Yellow River dikes of ancient times had been built up little by little over a thousand years; the Han dynasty had merely linked together the river dikes of the Warring States states of Zhao, Wei, and Qi.

But now, they would rise from flat ground! Starting from nothing! Even with the use of cement, the enormous cost could hardly be smoothed away.

Diwu Lun sighed with emotion. "No wonder you said that to quell the floods, it would take hundreds of thousands of men, ten years of labor, and coin and silk counted in the hundreds of millions!"

Not every ruler could resolve to undertake so great a task. Emperor Cheng of Han, Wang Mang, and even the emperors of peaceful eras before them — all must surely have faced such a moment. But before a challenge so immense, with its outcome so uncertain, they had all recoiled, halted, and chosen instead the lower strategy of minor mending and patching, leaving the problem for their descendants to "solve."

If that was so in times of peace, how much more so now, when the realm was not yet unified and the state treasuries still stood empty?

Du Shi understood the difficulties too, and his words were earnest: "But if it can be done, it will secure the great river for several hundred years!"

"Several hundred years, is it?" Diwu Lun pondered at length, then finally smiled. "Enough grand talk. Go and do it. The self-renewing soil is yours, the manpower is yours, the coin, silk, grain, and fodder are yours too. Before unification, first repair the Honggou canal mouth and the stone dikes at the river's juncture with the Ji for me."

"As for what comes after — I will support you. Do your utmost. If you can accomplish it within my lifetime, what would it matter to grant you a marquisate of a thousand households?"

With that, Diwu Lun clapped Du Shi on the shoulder and left the hall.

Du Shi bowed low behind him. It was not that he coveted the promise of a "thousand-household marquisate" Diwu Lun had dangled... Well, all right — it was indeed an immense incentive. After all, under the Great Wei system, a civil official or technical bureaucrat with no military merit might manage to earn a viscountcy, a barony, or even a countship, but a marquisate was still precious.

"I am willing to spend my whole life accomplishing this task!"

Du Shi swore a vow in his heart.

"Let the great river, within the span of our dynasty's mandate, never breach again."

……

Joyous events lift the spirit. In the summer of the fourth year of Wude (AD 28), what gladdened Diwu Lun's heart was not only the establishment of the Eastern Capital and the settling of the river-control plans. In the height of summer, the sixth month, as Diwu Lun made an inspection tour to Puyang in Dong Commandery, a third piece of good news arrived in quick succession.

Wang Hong, the newly appointed Inspector of Yan Province, came to report: under the province and commandery's vigorous famine relief and military farming, the Red Eyebrows bandits in Taishan Commandery had lost the support of the surrounding populace. Forced by hunger to descend from the mountains and pillage, they had been trapped by Ju Wuba in a small township. The Red Eyebrows' last leader, Xu Xuan, beset by troubles within and without, had finally agreed to surrender to the Wei army.

More than that — when he heard the last few words of the letter, Feng Yan, the Grand Herald who had found the journey with the imperial entourage rather dull, actually rose straight up from his sitting mat!

"The strategist Fang Wang, traveling among the various warlords, urged Zhang Bu and others to form an alliance against Wei. Later, when our army attacked Lu, he fled with the Red Eyebrows and hid in Mount Tai. Now that Xu Xuan has surrendered, he has been captured along with him and presented to us!"