Chapter 64: Water Reservoir

The damp air mixed with the scent of earth and grass came in waves from beneath the door crack, as if making this gradually hot May return to the lush days of spring.

The rain gradually ceased.

Chen Mu led Wei Dalei, He Ying, and Tang Jing out through the door crack to the outdoors to conduct an on‑site inspection of the upcoming water diversion project.

The others, limited in self‑defense ability, remained inside the house.

"Considering Chen Mu's current limited ability, my idea is to use this rainwater downpipe to conduct diversion."

Tang Jing spoke, extending her hand to point at a white rainwater pipe standing vertically on the exterior wall of the storeroom.

The so‑called rainwater downpipe, commonly known as a rainwater drainpipe, is a pipe installed on the exterior wall of a building to drain rainwater from the roof.

"Should we collect all the water it drains and then divert it indoors?" He Ying asked.

"Of course not." Tang Jing laughed: "We simply cannot control that amount of water, and if we collect it at the bottom, the height might be insufficient."

"Height?"

"Without a pump as a power device, to divert water we can only rely on gravity, but the problem is that we not only need to bring water in, we also need to discharge it out; therefore, without a certain height difference, it is very difficult to achieve."

"Alright, but I still don't understand—how exactly would we implement it?"

"The general idea is that I intend to make an opening in this rainwater pipe, then connect a pipe; after this pipe enters indoors, it loops around and then connects back outdoors."

"Then we open an opening on the pipe that leads indoors, and additionally branch off a water pipe for our use. We do this because once it rains, the water volume inside the original rainwater drainpipe will become large enough to exceed our control, so we need a transitional measure."

Chen Mu pondered for a moment and asked: "If we open an opening on the vertical drainpipe, and if it's a light rain with insufficient water volume, could we still collect water?"

Tang Jing nodded: "Yes, the water inside the downpipe can hardly undergo free fall; instead it flows along the pipe wall in a spiral downward, so this is not a problem."

He Ying then asked: "But if that's the case, aren't we only able to use water on rainy days?"

Tang Jing smiled: "So we still need to build a water reservoir."

"A water reservoir…"

"It's not just a water reservoir, because this water, after gathering on the roof and draining down, will certainly contain many impurities, so we also need to carry out some simple treatment."

"For example?"

"For example, we cannot use the rainwater from the first ten minutes; we let it drain away. Additionally, at the front of the water reservoir I will add a screen and a sedimentation tank."

Everyone heard these terms.

Instantly, there arose a feeling of unreality.

"Don't be afraid; although it sounds complex, it's actually not that troublesome. In genuine water treatment, coarse and fine screens are mostly used in wastewater treatment—two large sets of equipment meant to ensure that the water entering the pump is of sufficient quality not to affect equipment operation. But for us, we only need to make a simple filter with a precision of under 0.1 mm. Moreover, the sedimentation tank need not be as long as the standards require; for drinking water, before boiling we can simply add an extra sedimentation step. As for the method of boiling water…"

"Stop!"

Everyone spoke in unison, interrupting Tang Jing's speech.

"Good grief, do you think we can understand this or what?" Wei Dalei felt his head buzzing.

Chen Mu roughly understood the idea, but terms like coarse screen and sedimentation tank left him bewildered.

He Ying vexedly said: "Tang Jing, be honest—did you spend all our sleeping time studying? Besides, school never taught us these things, right?"

Tang Jing, rarely feeling a bit embarrassed, smiled: "Then let me put it simply?"

"No need to explain; whenever you give orders, we'll just follow them."

Chen Mu also felt a bit helpless, but he was ultimately a bit quicker‑witted than Wei Dalei and He Ying, and immediately thought of a question:

"How big should the water reservoir be?"

Tang Jing said: "I've calculated this too. According to Shangshi residents' per‑person water usage, the daily domestic water quota is 120–180 L per person, which includes drinking, bathing, laundry, flushing toilets, etc. We'll take a round figure of 200 L, so each person's daily usage is 0.2 ml."

"We currently have 12 people, but we must also consider development, so we calculate for 50 people, which gives 10 ml per day. Based on Shangshi's rainfall frequency and recurrence interval over the past 20 years, I suggest storing water for 30 days, which comes to 300 ml."

"How much is 300 ml?" Wei Dalei asked.

"About the size of a small bottle of mineral water."

"That seems okay too."

"The water reservoir must be sealed to prevent evaporation, opened only when water is let in or out, but there will still be loss during use. Taking various margins into account, I propose building a water tank with an effective capacity of 400 ml, an actual volume of about 650 ml, and dimensions of 8 cm by 8 cm in length and width and 10 cm in height."

Tang Jing finished speaking.

The scene fell silent again.

Everyone was mentally estimating what such a tank would look like.

Chen Mu had long been accustomed to Tang Jing's erudition, but he still felt a bit unreal; he had thought of several possibilities, and had tried to ask a few times, but never found the chance to speak.

At this moment he hesitated a while, but in the end he held back.

Afterward he asked again: "Since the plan is already this clear, shall we start work right away?"

"That fast?" Wei Dalei blinked.

"Such a big project will surely take a long time." He Ying said.

"Well, the most important thing is to see how far Chen Mu and Da Lei's abilities have progressed." Tang Jing said this, then asked: "Chen Mu, pipes like this shouldn't be a problem for you, right?"

"Pretty much."

Chen Mu pondered a moment and said: "Moreover, the thicker the pipe, the easier it might be."

"That's not really a big deal; in plumbing work the greatest difficulty lies in connecting the pipes, fittings, etc. If it's plastic pipe, without hot‑melt conditions it's actually hard to achieve a seamless joint, but for you this is not a problem, so the precision required of the pipe itself isn't high—just don't let it leak."

"I'll do my best."

"As for the water tank, I actually think it's not a big problem—it's basically just an enlarged version of a room, and even the details are easier, at least no door is needed."

"But a water tank 10 cm high is still somewhat difficult for us, isn't it?"

"Well, I'll think of a way; if it really can't be done, we might need to erect a simple scaffold."

Tang Jing said this, seeing everyone look at her with frightened eyes, she laughed: "It's only 10 cm—it won't kill anyone if you fall; don't imagine it as the former 10 m, that's a completely different matter."

Everyone, recalling the many times we'd discussed the danger of falling from height, gradually felt relieved.

"Since that's the case, better early than late—let's get to work now."

Chen Mu extended his hands, which had been tucked in his pants pocket all along.

If we could actually build such a project with our own hands.

It would also be quite fulfilling.