Starting from the former Seibu Plant site, it looks like construction is beginning on an “underground tunnel to store rainwater.”
(Information provided by Hank @ Nishi2 sp)
Here it is↓
It’s the site of the former waste treatment plant next to Soyora Nishinomiya-Imazu〜
Here it is on the map↓
The address is 3 Hamamatsubara-cho, Nishinomiya City.
目次
What is the construction for? 💡
It appears to be work to install a large storage pipe underground, temporarily holding rainwater during heavy rain to prevent sewage from overflowing and reduce flooding⛏️
More specifically, it looks like this↓
Flood prevention
Temporarily stores rainwater that cannot be drained during heavy rain, preventing it from overflowing onto the ground surface.Improving combined sewer systems
Stores water so that untreated sewage does not flow into rivers or the sea when sewage treatment cannot keep up, then releases it after treatment.Disaster preparedness
Even if sewage treatment facilities stop during a disaster, rainwater and wastewater can be stored temporarily to reduce damage.
Where is the construction area? 🗺
On the map, the following are shown:
- Current construction area (red line): Hamamatsubara-cho to Koshien 9-ban-cho
- Future construction area (green line): Former Seibu Plant site to the east, and other areas
- Completed area (black line): Higashi High School to the south, and Higashi High School to the east
This time, the construction will cover the area marked by the red line, from the “former Seibu Plant site to Nishinomiya Municipal Nishinomiya Higashi High School”〜
A quick look at the work 🔧
Shaft construction: Building vertical shafts that serve as the “entrance” or “access points” for underground work
- Location: Hamamatsubara-cho (former Seibu Plant site)
- Diameter: Approx. 15 m
- Depth: Approx. 35 m
Shield tunneling work: Excavating a “horizontal underground tunnel” that carries rainwater
- Location: Between the former Seibu Plant site and Nishinomiya Municipal Nishinomiya Higashi High School
- Pipe diameter: 3.25 m (outer diameter 3.6 m)
- Depth: 18-24 m
- Length: Approx. 2,080 m (2 km)
The underground tunnel being dug this time is over 2 km long! If you include the completed sections and the future sections too, just how long will it end up being? 😳
By the way, separate from this construction, a similar underground storage pipe is also being built under the Tsutogawa River as a heavy rain countermeasure. We previously wrote an article about how that construction is going〜. It’s seriously massive!
Here it is↓
How long will construction take? 📅
The construction period for this section is from October 2025 to around December 2029. It is scheduled for completion in 2029, and is expected to take about four years.
The future sections to be built from 2030 onward are expected to take until around fiscal 2044 at the latest.
Finally
Once this construction, which will continue overall until fiscal 2044, is completed, it should be able to handle heavy rain that occurs once every 10 years (55 mm of rainfall in one hour). It’s surprising to think such a massive project is moving forward underground! It really is a big project protecting the city from places we can’t see〜
※Hank @ Nishi2 sp, thank you for the information!!
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