I was going to publish this article last year, but it was all too late and the year has come and gone. Hi, it's time for the Dumb Log.
Last November 2021, Yahagi Dam was conducting an alternative discharge for power plant inspections, and I was invited by Masaki Hagiwara, an infrastructure YouTuber and dam photographer, who said he would be covering the event on video at the right time. I immediately said "I'll go!
Sato no Eki Cafe
In the morning I visited Kuroda Dam and Tominaga Dam for the first time in a while and had lunch at Satonoeki Cafe in Kushihara, Ena City. It was very delicious and I recommend it.
Looking downstream from the right bank
Arrived at Yahagi Dam. Arch dams are cool after all! This is not just any arch dam, but the first parabolic arch in Japan (and probably the first in the world). The Yahagi Dam is truly a milestone in the history of arch dams. In addition, the Yahagi Dam is one of the only dams in the world to use a two-stage pumped storage reservoir for hydroelectric power generation. In addition, the Yahagi Dam is the dam that awakened me to become a dam enthusiast.
Meet up with Mr. Hagiwara
We will meet Mr. Hagiwara at the parking lot on the right bank and head for the management office. Mr. Hagiwara will continue to take photos of the materials while we are there.
View of the discharge from the conduit gate from the top edge
This is a view of the discharge from the conduit gate at the top end. The Yahagi Dam is often seen discharging water through a conduit gate, including alternative discharge, so it may not be that unusual, but it is still a powerful sight to see.
In Yahagi Dam Management Office
I went to the control center, greeted the director and other staff members, and went to the operation room. The Kronoro-which I saw during the tour at the 12th Gathering with Dam Lovers when it was flooded by Typhoon No. 24 in 2008-was gone, but I was reminded that this was the front line during floods.
The Yahagi Dam serves as the lower reservoir of a two-stage pumped storage power plant, which is rare in the world. Chubu Electric Power does not contact the management office when they use or stop water for power generation or when they pump up to Tominaga Dam, so they have to monitor the actual water level. I was a bit surprised by this.
elevator
There was a sign on the elevator that said, "Private conversations are strictly prohibited. This was not to concentrate on work, but to prevent new coronavirus infection.
staircase in an audit corridor
It is hard to tell from the picture whether it is going up or down, but it is a down staircase. Can we go down? but Mr. Hagiwara was adamant about it, so we decided not to go down. If it were me, I would go down the stairs.
Normal course catwalk
This is the angle that you will be shown when you sign up for an official tour. On this day, the discharge was 14.69 m3/s.
I took my son to see this when he was still small, and it brought back memories of him crying because he could see underneath due to the perforated metal floor and the roar of the water discharge that scared him.
Incidentally, the gate on the right bank is fully opened, but it is due to an inspection.
Up close and personal with discharge from conduit gate
Here comes the special stage! We were shown the conduit gate at close range. This is the first time I have ever seen a discharge this close up.
View of the abatement pond from the catwalk
How amazing (vocabulary)!
I can't believe I got to see it from this distance...
I had seen the conduit gate when it was not discharging water at close range at the meeting with dam enthusiasts, but I never expected to see it during discharge.
Catwalk on the way to the conduit gate operation room
Next, you will be shown the conduit gate operation room. Once there, you will take the elevator up and take the catwalk stairs down.
Conduit gate operation room
The hydraulic cylinders are impressive in this room. Just at this time, I heard a "gong gong..." sound, which seemed to be the closing of a conduit gate that had been fully opened for inspection. I regretted a little that I should have seen it.
View of the discharge from the catwalk between the gate operation rooms
This is the first time I've seen the discharge from this angle.
Fence of crest gate operation room at top end
We came to the top end through a conduit gate on the downstream face. This fence was installed very recently.
Entrance to the Crestgate operation room
What a treat to be shown the inside of the Crestgate operation room! This room is not directly connected to the control center by a passageway, but you have to go outside the control center, walk along the top edge, open the hatch, and go down by a ladder. It would be very difficult to operate the crest gate from the side of the gate, but it must have been extremely difficult to get here in the torrential downpour. The only time in the 50-year history of the Yahagi Dam that the crest gate was actually operated was during the torrential rainstorm in Tokai (Enan) that occurred in 2000.
Crestgate operation room interior
It is a very small room, about four and a half tatami mats in size. About one-third of the room is occupied by the machine-side operation panel, which can be seen on the left, and the green thing on the lower right is the shaft of the radial gate. As I have said many times before, it is really hard to come to such a place in heavy rain.
crest gate
This is the first time I've seen the crest gate of the Yahagi Dam from this angle. It's cool, but I'd rather not use it if I could.crest gateI love it. The mechanical look is also super cool. Incidentally, the color of the DamPedia site is blue, which I took from the color of the Yahagi Dam, which is where I first became interested in dams.(Half of this is a lie. I just came up with the idea to make it that way)
Selective water intake system
Selective intake facility at Yahagi Dam. Water taken in from this facility is fed to the power plant downstream. This time, there were people working on the selective intake system, perhaps because it is being maintained as part of the inspection of the power plant.
I have been to the Yahagi Dam many times, but hearing again about the torrential rains in Tokai and how hard it is to manage the dam made my head spin. And thank you for showing us places and angles we had never seen before!
The video of the event was uploaded to Mr. Hagiwara's YouTube channel, SiphonTV, so be sure to watch it as well. (Don't forget to like and subscribe to the channel!)
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