Inside Nishinomiya’s Huge 41m Underground Pit | Nishitsu Detective

Two years ago, Nishi2 wrote an article saying, “They’re building something along the JR tracks.”

This is the building↓

＜Photo from two years ago＞
Near where the JR tracks and the Tsutogawa River cross, some mysterious huge thing was being built!

That’s what we reported.

Here it is on the map↓

The address is 6 Jingikancho, Nishinomiya City, Hyogo Prefecture.

So!

Welcome to “Nishi2 Detective,” the series where Nishi2 writers investigate Nishinomiya’s mysteries and questions and turn them into articles.

The Nishi2 Detective has infiltrated the “mysterious huge thing” we reported on two years ago, so we’ll show you what it was like.

GATE3

We were contacted by someone from a certain organization, saying we could enter the mysterious facility we had previously written about.

To solve Nishinomiya’s mysteries and protect everyone’s smiles, Nishi2 headed to the site with the mission that “we have no choice but to go.”

Together with people from many organizations, we were drawn into that mysterious facility.

It says GETE3. Are there other entrances too?

Hm? Right after entering, there’s something there.

Fall arrest? Are we going to fall???

You can see an excavator in the back.

It’s huge. This was a massive facility big enough for an excavator to enter.

There’s a huge amount of what looks like soil in containers. From where? And what did they dig out?

Are they pouring something in?? The pipes are arranged in a complicated maze.

Could this be a nationally important facility?!

It looks like we’ve finally reached the spot in question.

The Mysterious Giant Hole

We stopped after going all the way to the back of this facility.

They’re peering down at something.

What could be there?

What on earth is this?!

That’s scary.

So, since some of you may have sort of figured it out from the quiz, here’s the reveal.

This↓

Daiho Corporation’s Phantom River “Under River Project”

It’s an underground storage pipe. When you type it in Japanese, the conversion suggests “storage hall” instead

You’re probably thinking, “A what?”

They’re digging a huge 1.7 km underground tunnel directly beneath the Tsutogawa River to store rainwater like this.

They’re building an underground facility to prevent flooding in the city. In other words, it becomes a river when heavy rain falls

In technical terms, it’s the “Class B River Higashigawa System Tsutogawa Underground Storage Pipe Development Project.” That’s a loooong string of kanji

Here it is on the map↓

The total length is 1.7 km. They’ve currently dug about 400 m

The facility is scheduled to be completed in September 2025. The excavation itself is expected to be finished around February next year

Scene of a sudden downpour around Nishinomiya-Kitaguchi

As you all know, the Tsutogawa River area has suffered flooding many times in the past.

Near National Route 171 in 2013↓

Serious flood damage occurred.

Once this facility is completed, it will reportedly be able to withstand heavy rain that occurs once every 20 years. Apparently, the current system can only handle rain that occurs once every 5 years

Also, as Nishinomiya locals, there’s something important to mention.

As you know, Miyamizu flows underground in Nishinomiya.

Miyamizu is the ultimate water for making sake: rich in minerals and low in iron. That’s the quality of Miyamizu. Hard water and soft water are naturally blended together

The construction is being carried out on the premise of preserving Miyamizu.

They were conducting a Miyamizu survey like this.

By installing the storage pipe underground in the clay layer 21 m to 41 m deep, below the Miyamizu aquifer located 2 to 6 m underground, the project is designed with consideration for the Miyamizu environment.

So!

Going Down into a 41 m Hole

We’re going down 41 m underground.

Do you know what this is?