Niigata Prefecture Dam

0500-Okutadami Dam

0500-Okutadami Dam Niigata Prefecture Dam
This article can be read in about 7 minutes to read.

Date of interview: 2009/06/20
Location: Aza Otori, Yunotani Imokawa, Uonuma City, Niigata Prefecture

Okutadami Silver Line Entrance and Exit

I have wanted to visit Okutadami Dam for a long time! And the Okutadami Silver Line, which I had dreamed of! There are 19 tunnels in total, 18.1 km of tunnels out of 22.6 km of the Silver Line! Originally, it was a road for transporting materials for the Okutadami Dam construction, in other words, it leads to the Kurobe Dam's Kanden Tunnel.

I had wanted to run it, but when I came to it, I got tired of the tunnels that went on and on and on and on, and almost skipped it (sweat).

View of the embankment from the left bank downstream

So, after passing through the long tunnel, there is a large parking lot and you can see the dike first hand. I was surprised to see that it was quite a tourist attraction since the parking lot is quite large. I remembered that there was a tour of Okutadami on the advertisement of a local travel agency.

Okutadami Dam boasts the second largest total water storage capacity in Japan after Tokuyama Dam. It is also the fifth-highest gravity concrete dam in terms of embankment height and effective water storage capacity.


There is a sightseeing boat pier and an electric power building on the hill on the left bank, and able-bodied people can walk up the slope, but it is also possible to take the incline. The fare is 100 yen.

View of the downstream bank from the left bank

It's dignified, or whatever you want to call it. And even looking at it like this, it is quite tall. The height of the embankment is 157 meters.

View of the nameplate and embankment from the left bank

It is very unfortunate that it is cloudy after having come all this way.

View of the top edge from the left bank

It is quite a tourist attraction, but it is a very simple top end. There is nothing superfluous. It is like that.

Nameplate of the 100 dam lakes and power supply development

The dammed lake "Okutadami Lake" is certified as one of the 100 best dammed lakes. Well, it is not surprising that it is recognized as one of the 100 best dam lakes. Incidentally, the dam lake is also called "Ginzan Lake," which was named after a silver mine that once existed there. On the map, it is called "Okutadami Lake," which is the standard name.

View of Okutadamiko sightseeing boat

There is also a magnificent sightseeing boat on the dammed lake, again showing why it is a tourist attraction.

shrine receiving offerings of electricity

Walking further up the hill, you will see a power shrine on your left.

shrine receiving offerings of electricity

View of the embankment on the lake side of the dam from the high ground on the left bank

Climbing up here, you realize that that huge dike is supporting this abundance of water! You can really feel it.

Okutadami Denryokan

If you look closely, you can see that the electric power building itself is shaped like a water mill runner.

View downstream from the top

It is indeed high. Downstream, the road turns to the right and leads to the Otori Dam. The road downstream is off-limits to the public.

View of the substation from the top

This is the substation where the terrorists supposedly put up the parabolic antenna in the movie "Whiteout". I thought the actual location was different.

View of the dam lake from the top

Even though the Tokuyama Dam has lost the No. 1 position, it is still a large and huge dammed lake.

View of the top edge

The light blue line in the middle is just the border between Niigata and Fukushima prefectures. I went back and forth between Niigata and Fukushima prefectures. Come to think of it, I had never been to Fukushima Prefecture. My first visit to Fukushima Prefecture! I was deeply moved. Come to think of it, I used to work part-time at Kitakata Ramen when I was a student. Ever since then, I have always wanted to try the real Kitakata Ramen, but as you can imagine, it is impossible to do so here (lol).

Oh, and I had actually planned to stay overnight in Fukushima Prefecture to come to this dam, but Mr. Miyajima told me that I should not do that and that no one from the Kanto region would enter from Fukushima~. Later, I did some research and found out that the national road from the Fukushima Prefecture side is a bad road....

By the way, from this point on, you are not allowed to enter without permission.

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

It is so huge that the other side of the river looks very far away. What is that triangular pillar in the middle?

View of the water intake from the right bank

The Okutadami Dam has four intakes, one of which is relatively new, and the downstream outlet is also fairly new. A photo of that will come later...

View of the downstream bank from the right bank

All the buildings on the other side of the river look small. In this way, the souvenir shop and the cafeteria were standing on the edge of the cliff. The microbus that took us from the power station to the top of the river was on its side. It must have been very difficult for the bus as it had to turn around many times.

gantry crane

The gantry crane is also huge. The "IHI" logo is proudly displayed.

corridor connecting an annex to a pond-side building (in traditional palatial-style architecture)

Ah, this sensation! This coolness! This is what an audit corridor should be like! This unique sensation that you can never experience in your daily life or even when you come to visit the museum. This smell that somehow, someway, feels like a faint sense of pride in a closed space!

Inside the power plant

And when you enter the power plant, it looks like a huge gymnasium. In the center is a huge, not a trampoline. A generator is sitting in the middle. The generator is made by Tokyo Shibaura Electric ... Toshiba.


Because the power plant has such a large and high space, a crane is used to move heavy objects, and of course the wire used for the crane is also very large, thick, and long.

corridor connecting an annex to a pond-side building (in traditional palatial-style architecture)

Unlike the previous audit corridor, this one appears to be hand-carved. It looks more like a tunnel than an audit corridor. Incidentally, there are several Honda scooters at the back of the corridor, and it is said that the scooters are used to travel downstream to the Otori Dam. Of course, there are no holidays for electric power, so the scooters are used for inspection and troubleshooting during the winter, but since it snows heavily, the scooters cannot run outside, and the Otori Dam is connected by a narrow tunnel that can only fit one scooter! The outer wall of that tunnel can be seen on the way to Otori Dam.

I can just imagine the workers dutifully riding their scooters through those long, narrow tunnels in the middle of winter, and I am filled with awe that they are the ones who keep the power flowing! I am filled with awe. It's not the same as working overtime alone at the office.

Audit corridor near the entrance/exit just below the dike

Now, through here, just below the dam! I'm so excited!

Looking up at the embankment from directly below

As soon as they step outside, everyone is in awe. Everyone was taking pictures as they pleased. I also took many pictures, but after taking them, I kept looking at the scene. I looked at every detail of the building. And I remember the hard work that went into the construction of this huge building.

irrigation water discharge

The water is beautiful in this way. It is different from the water downstream in the city center.

View of the reduction work

If you look closely, you can see that the end of the conduit wall is sharp and has a really interesting shape. I would love to see the discharge of water from here.

Outlets from Units 1-3

The microbus then moved further downstream to the Otori Dam. On the way, we saw the outlet from Units 1-3. It is really old and has a tasteful atmosphere.

Discharge outlet from Unit 4

This is the discharge port from the latest Unit 4. This one is new and beautiful, but it is quite normal or simple.

Okutadami Dam Specifications

River NameAgano River System Tadami River
Objectivegeneration (e.g. power)
Modelgravity-fed concrete dam
Bank height157m
Bank length480m
Dam volume1,636,000m3
Watershed Area594.6 km2
Reservoir area1150 ha
Total storage capacity601,000,000m3
Effective water storage capacity458,000,000m3
Dam operatorPower Development Co.
Main body constructorKajima Construction
Year of launch1953.
Year Completed1960.
Name of Dam LakeLake Ginzanko

Other facilities/observations

It is a dam worth going to. It was indeed a long way... The parking lot is probably the largest of all the dams I have been to. Fishing is only allowed upstream of the dam lake, as the downstream area is off limits to the public.

Parking lot
PR Exhibition Hall

Books/DVDs that may be related to Okutadami Dam

Accommodations that may be close to Okutadami 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.

Follow Damapedia


  1. 名犬太一郎 says:

    I went to the Silver Line for the second time today. I went to the fence on the right bank and was overwhelmed. I have only been to Toyooka Dam in Suzaka City, Nagano Prefecture, and Omachi Dam and Kuroshi Dam in Nagano Prefecture, but I am secretly convinced by the recent increase in dam fans and my own targeted popularity of dams. Dams are truly amazing. I pray for the souls of the many people who were killed by these construction projects.

  2. 神馬 シン says:

    >Master Inu Taichiro-sama.
    Thanks for your comments. An amazingly long tunnel and an overwhelmingly high dam. I am honestly surprised to find that there are surprisingly many dam fans since I started Twitter. The scale of the dam is amazing, but we must not forget that it is an infrastructure that protects us. For that reason, I would definitely like to join hands with the cenotaph.

Copied title and URL