"I noticed something while observing the local terrain from the air," Jin began, spreading the photographs across the office table to begin his explanation.
"Something you noticed?" Lishia asked.
"Right. Look here... You can see that a massive amount of water is stored within the Great Shama Marshland, can't you?"
"Yes, that's true."
"Where do you think all that water comes from?"
"Eh...?" Lishia stared at the photographs Jin had laid out, eventually pointing to a specific spot. "Um, isn't it from around here?"
She was pointing to the section where the Naudo River emptied into the marshland.
"You're not entirely wrong, but that isn't the primary source." Jin shook his head with a small smile.
"It isn't?"
"No. Some of this is still just my own theory, so I'll need to conduct a proper survey afterward, but I believe the vast majority of the water in the Great Shama Marshland is actually subsurface flow."
"Subsurface flow... You mean water that flows underground?"
Jin nodded. "That's exactly right. Now, where do you think that flow originates?"
Lishia tilted her head, pondering the question.
"This is where my theory comes in. I believe it comes from the surrounding mountains."
Mountains stretched along the eastern and northern borders of the Great Shama Marshland. Moist winds blowing from the sea to the east of the former Leonard Kingdom would hit those eastern mountains, forming clouds and falling as rain.
Furthermore, the northern mountains weren't the ones immediately north of Toka Village, but the towering peaks situated north of Kaina Village.
"Glaciers cling to those peaks, and the mountains just south of them receive a high volume of precipitation. Not all of that water ends up in the Erme River."
"Ah, I think I understand what you're getting at."
"Right. And I know for a fact that there's a massive amount of groundwater beneath Kaina Village because I've surveyed it."
The fact that hot springs welled up there was a direct benefit of that subsurface flow.
"Given the sheer volume, it wouldn't be at all strange if that water traveled deep underground to reach the Great Shama Marshland."
"...I think I see where you're going with this." A look of hope flickered across Lishia's face as Jin's point began to dawn on her.
"In other words, you think there might be groundwater beneath Toka Village as well?"
Jin nodded firmly. "Precisely. But as I said, it’s just a theory until I investigate. I also don't know how much water we can actually draw out."
Naturally, if they extracted too much, it could negatively impact the environment.
"Even so, this is a real ray of hope."
"Alright, let's go test the theory right away."
Jin turned to head outside, then paused as a memory surfaced. Come to think of it...
He recalled making a magi-device for 'Ore Vein Prospecting' back in the world four hundred years in the future.
I should be able to make a magi-device for water vein and hot spring prospecting as well.
He remembered searching for hot springs in Reinhard's territory. He hurried outside and headed for the Konron 3, which was parked on the outskirts of the village. Using the spare parts and maintenance materials stored inside the craft, he set about constructing a 'Water Vein Prospecting' magi-device.
As he worked, further ideas occurred to him. It might be useful to make it switchable so it can also detect hot springs, minerals, or magi-crystals.
"U-Um, Jin-san?"
Lishia had followed him out when he suddenly bolted for the Konron 3, and she now stood there with a bewildered expression.
"Lishia-sama, Father is currently crafting a magi-device to locate underground water veins," Reiko explained.
"What!?"
Lishia was stunned by Reiko's explanation, but she quickly composed herself. It's Jin, she thought, so I shouldn't be surprised by anything he does.
"Alright, it's done."
Jin emerged from the Konron 3 holding a magi-device that resembled a large flashlight. Having made a similar device before—technically four hundred years in the future—he had completed the work with remarkable speed.
"Can you really find water veins with that?"
"Yeah. If you point this at the ground and activate it, this magi-crystal here will glow green if it detects a water vein. If it does, you flip this other switch, and the approximate depth will be displayed on this ultra-compact magi-screen."
The device utilized 'Sonar' to measure the depth of any discovered veins. Jin estimated the margin of error to be within roughly ten meters.
"Wow... That's incredible."
"Now, let's give it a try."
They started at the highest elevation point north of Toka Village. If they could find a water source here, distributing it would be easy.
"Time to wake it up... Oh, there it is."
"You found one!"
Neither of them had truly expected to strike gold on the very first attempt, and both Jin and Lishia were overjoyed.
"The depth is... 250 meters. That's quite deep."
Jin considered it deep for a water vein, but decided to try digging a test well anyway.
"Reiko, I'll handle the excavation. You apply 'Dissolute' to the shaft as I go."
"Understood. Leave it to me."
"Alright, here we go... 'Dig'!"
"'Dissolute'."
Working with even better coordination than he had shown with Reinhard, Jin and Reiko used 'Dig' and 'Dissolute' in perfect sync, reaching the water vein in a mere two minutes.
"We've reached it."
"Eh, already?"
Lishia peered into the twenty-centimeter diameter hole.
"Now, I wonder what the water pressure is like down there... Hm?"
"Kyaa!"
Suddenly, a geyser of water erupted from the hole.
Jin and Reiko were unfazed, but Lishia, who had been peering directly into the shaft, took the full force of the spray and was instantly drenched.
"Uuu... It's cold."
"You should change quickly... No, wait, this is faster. 'Dry'."
Since magi-craft generally has no effect on living tissue, Jin was able to dry Lishia's clothes without affecting her body. Had he used 'Heat,' there would have been a risk of the water reaching scalding temperatures and causing burns.
"Ah, thank you. That's much better." Lishia breathed a sigh of relief as the moisture vanished. "Wait—more importantly, the water actually welled up, didn't it?"
"Yeah. We're lucky it's under enough pressure to be self-spouting. That saves us the trouble of installing a pump."
As he spoke, Jin quickly excavated a reservoir to catch the water.
"Phew, that should do it."
The resulting pool was roughly the size of a twenty-five-meter swimming pool, with a depth of about two meters.
"Reiko, let's split up and reinforce the sides."
"Yes, Father."
They left the bottom as natural earth but lightly reinforced the walls to prevent them from collapsing.
"Next, I'll need to build a fence so no children accidentally fall in..."
"Ah, we will handle that ourselves," Lishia interjected. She felt guilty leaving absolutely everything to Jin.
"Fair enough. After that, you'll just need to manage the overflow."
That would require the installation of an outlet and a water gate for regulation.
"Yes, we can manage that as well."
It looked like it would take about two days for the reservoir to fill, which gave them plenty of time to prepare.
"Jin-san, thank you so much. This will completely change the lives of everyone in Toka Village."
"I'm glad. Just keep working hard."
With an abundant water supply, the village could grow a much wider variety of crops. It seemed even rice cultivation was now within their reach.
From this year forward, Toka Village's food self-sufficiency rate eventually climbed to well over 100 percent.