Tochigi Prefecture Dam

0582-Yashio Dam/Yashiodamu

4.0
Tochigi Prefecture Dam
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Location: Momura, Nasushiobara City, Tochigi Prefecture; Shimoshio, Shiobara Town, Nasugun
Date of interview: 2010/04/26

Nasushiobara Station

Nasushiobara Station

The 9th Dam Web Ring Off-line Meeting "Yashio, Snake-tail Riverdam tourI went to the "Shinkansen" in Tokyo, Japan. I had to make a day trip because I had to work on the day before and after the trip. So I took the Shinkansen. However, it was not cost-effective because I could see only two units for the high cost of the trip........

After taking the Tokaido Shinkansen from Nagoya and transferring to the Tohoku Shinkansen at Tokyo, we arrived at Nasu Shiobara Station.

Board the bus

Board the bus

Then we boarded the bus that was waiting for us in front of the station.

Arrive at TEPCO Shiobara Land

Arrive at TEPCO Shiobara Land

We arrived at TEPCO Shiobara Land. Here we met up with TEPCO and the private car group.

The forbidden gate is opened...

The forbidden gate is opened...

The public is prohibited from entering beyond this point. Photos of this gate are often posted on the websites of other dam enthusiasts. However, today is special. This gate will be opened.

Arrival at Yashio Dam

Arrival at Yashio Dam

We climbed up the mountain road and arrived at the Yashio Dam.
The Yashio Dam is quite a climb because it serves as the upper reservoir for the Snake River pumped storage power plant.
By the way, the lower pond is the Snakeo River Dam.
Then, as soon as you get off the bus, a commentary by TEPCO will begin.

View of the dam lake from the right bank

View of the dam lake from the right bank

The lake is quiet.
Perhaps due to the high altitude, the scenery does not yet feel like spring, even though it is April.

View of the embankment on the lake side from the right bank

View of the embankment on the lake side from the right bank

The Yashio Dam is an "asphalt-facing fill dam," a rare type of dam in which the water barrier on the lake side is covered with asphalt. Moreover, it is the largest asphalt-facing fill dam in the world.

The different colors are because there are instruments under them.

View of the water intake gate

View of the water intake gate

The intake gate for power generation sits daintily at the dam site.
Below are the intake gate specs.
Net diameter x door height: 8.00m x 8.50m
Number of gates: 1
Opening/closing speed: 0.5m/min
Door weight: 121.4t
Date of production: November 1992
Production: Hitachi Zosen Corporation

View of the dam name monument and the embankment

View of the dam name monument and the embankment

There was a person who was eating his lunch using a monument with the name of the dam as a table (laugh).

View of the right bank from the center of the top edge

View of the right bank from the center of the top edge

It is a fairly wide top end.

View of the left bank from the center of the top edge

View of the left bank from the center of the top edge

There are no general tours, so there are no fences or anything like that.

View downstream from the top

View downstream from the top

And it is quite a steep slope. It is so steep that if you roll down it, you might end up at the bottom.

View of the conduit from the top edge

View of the conduit from the top edge

It is a relatively large conduit, although it is dedicated to pumped storage power generation, so it will rarely discharge water. I am more concerned about the truncated road.

View of the wall on the dam lake side from the top edge

View of the wall on the dam lake side from the top edge

Thinking back, I don't think I have ever seen asphalt facing up close like this.

View of the flood discharge from the top

View of the flood discharge from the top

This is a natural overflow flood discharge. I don't think it will have much chance to be used, as I think it can discharge enough electricity to generate power.

View of flood discharge

View of flood discharge

This type is often seen in rockfill dams.

View of the conduit

View of the conduit

The structure seems to be quite steep, and it is difficult to see what is ahead.

View of the levee downstream from near the entrance to the audit corridor on the left bank

View of the levee downstream from near the entrance to the audit corridor on the left bank

From here, it looks like a rock-fill dam.

View downstream from near the entrance to the audit corridor on the left bank

View downstream from near the entrance to the audit corridor on the left bank

The slope is quite steep.
Now it is time to enter the audit corridor.

Audit corridor (down stairs)

Audit corridor (down stairs)

We finally entered the audit corridor. The Yashio Dam does not have an elevator, and all patrols are on foot. Still, I can't see what's ahead...

Audit corridor (looking up on the way down)

Audit corridor (looking up on the way down)

I wonder how far we have come down.... Even though it was a downhill, my knees were shaky and my breath was wheezing.

Audit corridor (deepest part)

Audit corridor (deepest part)

I finally made it to the deepest point. It should be cold, but I am sweating.

laying a cornerstone (foundation stone)

laying a cornerstone (foundation stone)

What a place for a cornerstone!

Audit corridor (looking up stairs from the deepest part)

Audit corridor (looking up stairs from the deepest part)

Now, the next step is up.... Hell awaits you.

View of the embankment from the exit of the audit corridor on the right bank

View of the embankment from the exit of the audit corridor on the right bank

I ran all the way up the hill of hell (a lie) and out to heaven.
The other side is where you just entered.

View of the conduit from downstream

View of the conduit from downstream

And next we move directly downstream.
Very steep.conduitThe following is a list of the most common problems with the

View of the levee from downstream

View of the levee from downstream

The dike does not fit all the way in. By the way, the camera at this time was a Panasonic FZ-30.

View of the conduit wall

View of the conduit wall

Surprisingly small for such a steep conduit.sub-damAnd And.momentum reducerThe following is a list of the most common problems with the

View of the levee from downstream

View of the levee from downstream

The whole thing doesn't fit in and is cut off here and there.

Looking downstream

Looking downstream

The flow rate is not so high as to be called a river.

View of the flood discharge from downstream

View of the flood discharge from downstream

There are stairs by the conduit, but they must be heartbreaking stairs.

View toward the top edge from downstream

View toward the top edge from downstream

Hmmm, a bit oblique.
Still, the neatly arranged riprap is impressive.

Mysterious structure

Mysterious structure

Back to the top edge again. Mysterious structures around the dam lake...

administration office

administration office

This is the management office. I used the restroom here.

Shiobara Underground Power Station...

Shiobara Underground Power Station...

And next we will head to the Shiobara Underground Power Plant.

It's like a secret base.

It's like a secret base.

This is the entrance to the underground power plant. The entrance to the underground power plant is usually closed, and it is very strictly guarded. The atmosphere is quite austere. The trucks running in front of us are just passing companies, but they look strangely like them. It is an important base that supports the infrastructure of electricity, so they must be protecting it well.

We're heading to the secret base, too.

We're heading to the secret base, too.

Following the truck in front of us, we enter a secret base...or rather, an underground power plant.

In Shiobara Underground Power Plant

In Shiobara Underground Power Plant

It looks like a big gymnasium. I have seen this kind of power plant several times before, but it is still very spacious.

Experimental Water Car Runner

Experimental Water Car Runner

These exhibits are installed in the power plant and these are explained to the visitors.

Cross-section of Yashio Dam impervious wall

Cross-section of Yashio Dam impervious wall

A cross-section of the asphalt barrier wall of the Yashio Dam fits directly into this box.

power cable

power cable

In addition, power cables cut into rings are also exhibited.
The tour of the power plant ended with the following words.
Next, we will come to the Snake River Dam, but more on that later....

dam characteristics

River NameNaka River system Nabearisawa River
Objectivegeneration (e.g. power)
ModelAsphalt-facing fill dam
Bank height90.5m
Bank length263m
Dam volume2,109,000m3
Watershed Area2km2
Reservoir area47 ha
Total storage capacity11,900,000m3
Effective water storage capacity7,600,000m3
Dam operatorTokyo Electric Power Co.
Main body constructorMaeda, Taisei, Obayashi
Year of launch1980
Year Completed1995

Other facilities/observations

It is completely off-limits to the general public.
The PR exhibition hall is located near the "TEPCO Shiobara LandAlthough there is a "tour of the Shiobara Power Plant," it does not appear that tours of the Shiobara Power Plant are being conducted. →Closed.

Parking lot×
Toilet×
Park×
PR Exhibition Hall
Fishing×

Accommodations that may be close to Yashio Dam

This article was written by.
Shin Jinma

Dam enthusiast who loves Momosuke Fukuzawa / Dampedia and Dam News administrator / Certified Dammeister (01-018) by the Japan Dam Foundation / Started selling discharge caution goods.https://shop.dampedia.com

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