1057-Oi Dam

Location: Aza Okudo, Oimachi, Ena City, Gifu Prefecture
Date of interview: Thursday, March 10, 2011

View of the levee downstream from Shinonome Bridge

Oi Dam is a dedicated power generation dam owned by Kansai Electric Power Co. and has a long history, dating back to the Taisho Era (1912-1926) when it was completed.

Shinonome Bridge" located downstream of Oi Dam

Immediately below the Oi Dam, there is a bridge called Shinonomebashi (Shinonome Bridge), which is a mixture of a girder bridge, a steel bolstered truss bridge, and a reinforced concrete girder bridge. However, because of the narrow width of this bridge and the difficulty of alternating traffic, a new Shinonome Bridge (tentative name) is scheduled to be built downstream along with a bypass road (as of December 2012).

So far I have not heard anything about what will happen to this bridge after the new Shin-Tonome Bridge is completed, but I do not want it to be removed because without it, we will not be able to see the Oi Dam from directly in front of us like this....

Chubu Electric Power Company Okudo Power Plant

There is a small hydroelectric power station on the right side of the Oi Dam from Shinonome Bridge. The Okudo Power Station in the photo is owned by Chubu Electric Power Company and its water intake is upstream from the Agi River, which joins the Kiso River, so it is not directly related to Kansai Electric Power Company's Oi Dam.

View of KEPCO's Oi Power Station and Shin-Oi Power Station buildings from Shinonome Bridge

These are the buildings of the power plant with history and style. In the foreground on the left is the building that was constructed during the Taisho era, and on the right is the new Oi Power Station, which was newly constructed in 1983.

Oi Power Station Building, Kansai Electric Power Co.

Finally, we will go to the dike. It is possible to drive to the dike a little higher than the top level (near the switchyard), but it is recommended to walk along the observation path from here. However, depending on the season, the grass may be overgrown with weeds and cobwebs, so drive up to the top as soon as possible in that case.

sign (e.g. roadside, in park, etc.)

But if you are on foot, you will be climbing up a slope there, so it is not recommended for those with weak legs and feet.

They have a time capsule.

I heard that a time capsule is buried in the site of the power plant. 2097...I wonder if even my son will be alive, let alone me (lol).

observation corridor

I really appreciate the fact that a dam dedicated to power generation has a pathway for visitors like this.
It is also a dam with high historical value, as it is a modern civil engineering heritage and one of the 100 dammed lakes, so it is not surprising.

hydraulic iron pipe

As you continue down the passageway, you will see a large hydraulic iron pipe on your left. This is the point where I always have trouble taking pictures because I cannot get the whole picture. When you reach this point, you can hear the distinctive "boom" sound of the power plant.

Shin-Oi Power Plant

When you come to the end of the passage, you will see the Shin-Oi Power Plant building at the end of the passage.

Oi Power Plant

Little by little, we approach the embankment.
A full view of the Oi Power Plant building can be seen. The Shin-Tonome Bridge can be seen behind it, and the construction site of the new Shin-Tonome Bridge can be seen further behind it.

Surge tank top

The surge tank is located above the hydraulic iron pipe seen on the left side of the previous passageway, the top of which is visible at this position.

View of the levee downstream from the observation walkway on the right bank

And looking back, the embankment of the Oi Dam.

shrine honouring war dead

A shrine called Okutatari Shrine is enshrined in the middle of the pathway for visitors. I am more interested in "A bear has come out! I am more interested in the

View of the levee from the side of the gate for water intake control

We have finally reached the top level. We would like to get close to the dike right away, but before we do, there are many things to see on the right bank side.

Fumyoshosema "Oi Power Plant Kigong Monument" (Oi Power Plant Kigong Monument)

First of all, this is the "Oi Power Plant Kigong Monument". It reads "Fumyosekene wo terasu" ("The Fumyosekene is the best place to live."). It reads "Fumyo Seken wo Terasu" ("Brightly Illuminate the World"). It means "to shine a bright light on the world at large," indicating how important this hydroelectric power generation project was to Momosuke. It was selected by Momosuke Fukuzawa and written by Norihiro Iwasaki.

Below that, an outline of the power plant construction is written in the old script. The original and translated text here is from Hisa'sHydraulics.com has a description.Please refer to this page for more information.

Portraits of Momosuke Fukuzawa and other construction workers are embedded in relief on the reverse side of the monument.

Also, the stone on the side of the monument is actually a...oh, let's keep this a secret since you have avoided mentioning it on other websites.

Momosuke Fukuzawa, President

President of Daido Denryoku and also known as the "King of Electricity in JapanMomosuke FukuzawaThe construction of the Oi Dam was a difficult task. The construction of the Oi Dam was quite challenging, but with the help of Madame Sadayakko, Japan's first actress, who was also his business partner rather than his mistress, he was able to make the construction a success.

Eijiro Ishikawa, Deputy Director

Eijiro Ishikawa was involved in the design of the Oi Dam, and has been involved in many other hydroelectric projects, including the Kasagi Dam, Imawatari Dam, Kaneyama Hydroelectric Power Station, and Yaotsu Power Station.

Vice President Jiro Masuda

Jiro Masuda was originally a bureaucrat who entered the Ministry of Home Affairs and served as secretary to the president of the Railway Board, and in 1915 he became a member of the House of Representatives from the Rikken Doshikai. He then moved into business and was vice president of Daido Electric Power Co. at the time of the Oi Dam construction, becoming president of Daido Electric Power Co. in 1928 and the first president of Japan Power Transmission Co. in 1939.

Weir Chief Tomonaga Somezo

Tomonaga Somezo was an engineer in Tottori City and the designer of the Mitami weir. He was assigned to Oi Dam as the weir chief under the direction of Tojiro Sano (see below).

Mitsuhiro Ota, Managing Director

Mitsuhiro Ota was an official of the Ministry of Railways who joined Keihan Electric Railway shortly after its establishment and was appointed manager of the General Affairs Section. He later served as director and managing director, and was appointed president of the company in 1925. He also served as president of Mie Godo Denki.

Director and Manager Sueichi Murase

Sueichi Murase was in charge of local measures to develop the Kiso River and later became vice president of Daido Electric Power Co. Murase, who was from a samurai family, lost his family's stipend after the Meiji Restoration and was destitute, but he entered Keio Gijuku.

After graduation, he joined Furukawa Mining Co., and although he temporarily served in the military, he became a lecturer at Keio University after his discharge. He then joined Tokyo Electric Power Co. In 1913, he met Momosuke Fukuzawa, who was the managing director of Nagoya Electric Light, which led Murase to join Nagoya Electric Light as well.

When Kiso Electric Steel Company was established, Murase became the manager and was involved in the development of the Kiso River. He demonstrated his skills at the Okuwa, Yomiuri, Oigawa, and Ochiai power plants, and the suspension bridge near the Ochiai Dam was named Murase Bridge after Murase in honor of his achievements, which shows that he was a major player in Kiso River development.

Civil Engineering Advisor Tojiro Sano

Tojiro Sano is an engineer from Nagoya who is well known (?) to dam lovers. Sano Tojiro, who was born in Nagoya, is an engineer who is well known among dam enthusiasts. He is an indispensable figure in the story of modern waterworks projects. He was involved in the construction of the Tachigahata Dam, the Nunobiki-Gohonmatsu Dam, and the Toyotoshi Pond Dam. No wonder there are so many fascinating dams.

Yoshinobu Hatakeyama, Director

Yoshinobu Hatakeyama, who was also the second director of the Oi Dam, wrote a paper on the expansion and contraction of the embankment due to changes in outside temperature, which led to the introduction of "contraction joints" to prevent this problem. He was also dispatched to the U.S. to conduct research on the Oi Dam construction project.

Electricity Section Chief Takeo Saeki

I have no information about Takeruo Saeki....

General Affairs Section Chief: Tagaji Yokoyama

Tagaji Yokoyama later served as the mayor of Sohara Village (present-day Sohara, Kakamigahara City) and the first chairman of the Kakamigahara Water Supply Land Improvement District.

Foreign Bond Underwriter Clerance Giron

Clarence Giron (Dillon) was an American investor and president of Dillon, Reed & Co. He is also known as the man who revived the French wine Chateau Haut-Brion. He also later produced C. Douglas Dillon, former U.S. Ambassador to France.

Clifton M. Miller, Foreign Bond Underwriter

Sorry, I didn't have the information.

Construction Advisor F. M. Thiebaud

Sorry, I didn't have the information.

Panel embedded in the back of the monument

You can see that we relied a lot on foreign power.

Momosuke Fukuzawa and Sadayakko Kawakami

A precious photo of Momosuke and Sadayakko. Around them also seem to be pictures of people related to the Oi Dam, who are thought to be the people in the relief.

Monument of Yukichi Fukuzawa "Independence and Self-Respect

The inscription here is often mistaken for Momosuke, but it is that Yukichi Fukuzawa of the 10,000 yen bill. The inscription on the nameplate includes an explanation of the inscription.
Yukichi Fukuzawa widely advocated the rise of industry through hydroelectric power generation in the early Meiji era. His adopted son, Momosuke Fukuzawa, was inspired by him and realized his ideals by opening a channel in the Kiso River, building a dam, and generating electricity. In commemoration of the completion of the Oi Power Station, Japan's first dam-type power station, his portrait and his motto, "Independence and Self-Respect," are engraved on the wall in permanent commemoration.
In other words, Momosuke may have been Yukichi's best disciple.

Looking toward the control center from the right bank dam site

I remember that we used to be able to enter from here, but the gate is now closed. Incidentally, there is a silver post box on the left side. If it is in stock, there should be a KEPCO original folded dam card in it. Unfortunately, they were out of stock at that time (I even called to confirm...).

Water intake control gate door (roller gate with steel bypass valve) for Shin-Oi Hydroelectric Power Station

It is a gate with a kind of cool name.

Below are these specs.

Type and number of gates: 1 roller gate with steel bypass valve (watertight system, watertight on rear 4 sides, 2 valves Φ20cm)
Net spacing x net height: Front 5.994m Rear 5.712m x 5.35m
Gate width x gate height: 6.06m x 5.79m
Maximum design depth: 14.965m
Hoist output: 3.7KW
Winding speed: 0.3m/min at all times, 6.0m/min during rapid descent
Lift: 18.70 m
Door material: SS41, SM41A
Door weight: 28.0t
Date of production: December 1981
Name of manufacturer: Marushima Water Gate Manufacturing Co.

View of the levee downstream from the right bank

The Oi Dam and power plant were recognized as a Heritage of Industrial Modernization by the Ministry of Economy, Trade and Industry on November 30, 2007 as "a group of industrial heritage sites that tell the story of power supply development in the Chubu mountain region that supported the economy of the Kinki region and manufacturing in the Chubu region - hydropower related facilities on the Kiso River.

View of the levee downstream from the right bank

The neatly arranged gates are cool from all angles.

Looking downstream from the right bank

Does Momosuke also see this scenery?

Looking downstream from the right bank toward the dam lake

The perfectly aligned figure is very dignified.

View of the top edge from the right bank

Since the gate was repaired during the Showa period (1926-1989), it is difficult to see the Taisho period on the right side of the photo (downstream side), but the left side (lake side) retains a very Taisho period atmosphere with the design of the top railings.

View of the dam lake from the top

Mt. Ena can be seen beyond the dam lake. Oi Dam Lake has been recognized as one of the 100 best dam lakes by the Japan Dam and Water Environment Improvement Center.

View of the administration office from the top

The right side looks a bit like a factory, although there seems to be a dust remover and some other machinery.

Top edge lighting

Retro lighting goes well with retro dams.

Looking downstream from the top

Downstream of this dam is the Kasagi Dam and the Maruyama Dam.

railing at the top of a roof

The design of the railings is also quite unique. It has a tasteful atmosphere not found in other dams.

View of the top edge from the left bank

The top of the embankment is 275.8 m long, as you can see.

View of the power plant from the left bank

The old Oi Power Plant on the left and the new Oi Power Plant on the right.

View of the top edge from the left bank

Not limited to the Oi Dam, but I always want to take a photo of a line of things lined up in a row like this (lol).

View of the ceiling railing from the left bank

This is another photo of a lineup of people (lol).

Looking from the top to the left bank of the lake side of the dam

The left bank on the dam lake side is a walking trail.

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

The rows of Kanden black radial gates are spectacular.

Walkway on the left bank

As mentioned earlier, the left bank is a promenade. It is a good walking course.

offices of a public or governmental organization (organisation)

Back to the right bank and up the slope, there is an open/closed station. On this day, there was some kind of construction work going on.

Looking downstream from the observation walkway

We return again to the downstream viewing corridor. It seems that we had been there for quite a long time, and the sunlight reflected off the surface of the Kiso River, giving it a twilight color.

View of the levee

Here is a maximum telephoto view of the embankment on the way. This is an old dam from the Taisho era, but it also has a nice taste. The copper-brown color seems to be seeping out of the iron in the aggregate.

View of the structure on the downstream left bank side

It is a complex shaped structure. It may be like footings. It has a shape that you could look at for a long time and never get tired of it.

View of the top of the surge tank

Back to the observation corridor. There is a surge tank on top of the hydraulic iron pipe introduced at the beginning of this tour, and this is also Kanden black.

Surplus water discharge from surge tank?

At the far left before the entrance to the first observation corridor, there is a mysterious structure extending from the back of the surge tank. It may be some kind of residual water discharge. There is no sign of water flowing for a long time, but it is built in such a way that it flows into the Wada River just beside it.

At any rate, the Oi Dam is a dam with many sights to see, but why don't you come and feel the Taisho Romanticism? Why not feel the breath of Momosuke and Sadayakko as well?

Oi Dam Specifications

Other facilities/observations

Parking is available around the opening/closing station on the right bank elevation and downstream just beside the Shinonome Bridge. I don't think there were any restrooms.

Map around Oi Dam

Weather around Oi Dam

Accommodations that may be close to Oi Dam