989-Taiwu Dam/Yasooka Dam

Location: Taifu Village, Shimoina-gun, Nagano Prefecture
Date of interview：2011/03/24 (Thursday)

View of the levee from the plaza downstream on the right bank

March 11, 2011... Japanese people were shaken by an unprecedented earthquake. The Great East Japan Earthquake. That was the name given to the massive earthquake that occurred on that day. The tsunami generated by the earthquake hit the Fukushima Daiichi Nuclear Power Plant, resulting in a devastating nuclear accident.

This has led to a crisis of power shortages in TEPCO's service area.

I'll try to get a little closer to the dike.

At this time, Chubu Electric Power Co. Electricity in Japan is generally divided into 50Hz and 60Hz zones in the east and west, with 60Hz in the area under the jurisdiction of Chubu Electric Power Company and 50Hz in the area under the jurisdiction of Tokyo Electric Power Company. Moreover, only a maximum of 1,000,000 kW can be mutually transmitted.

Therefore, Chubu Electric Power Company modified the facilities at the Taifuji Hydroelectric Power Station, where the Taifuji Dam is located, and began transmitting 20,000 KW of electricity to Tokyo Electric Power Company on March 22, 2011.

I'll try to get closer to the dike.

In other words, we switched from 60 Hz operation to 50 Hz operation and began transmitting power. And in April, another 40,000 KW will be transmitted.

When I saw the news on March 23, I couldn't stand still and went to the Taifu Dam the day after I read the article to admire the sight of the dam.

Chubu Electric Power is also providing various other assistance to TEPCO.
>Chubu Electric Power Company Press Release "Consideration of Conversion Capacity Improvement as an Emergency Measure for Higashi-Seimizu FC

View of the Taifu Hydroelectric Power Station and the turret bridge

Now, I have to preface this a bit. Let us return to the introduction of the Taifu Dam.

Momosuke Fukuzawa, who led the successful development of hydroelectric power generation on the Kiso River, also embarked on the development of hydroelectric power generation on the Tenryu River. Although Momosuke had nothing to do with the Taifu Dam, it was completed in 1935 by Yahagi Hydro Co.

It is sobering to think that 50 Hz power generation is taking place there.

View of Gate Pier

The Taifu Dam has been selected as one of the "2000 Most Important Civil Engineering Structures in Japan," and the smooth curves of the embankment and the construction of this gate pier are also indicative of why the dam was selected.

View of the conduit on the left bank

The Tenryu River is a river with a large inflow of sediment due to the influence of the Fossa Magna. Moreover, the grain size is said to be rough. The coarse-grained sediments scrape the surface of the embankment, which is why the concrete surface is so white.

In the past, the coarse-grained sediment of the Taifu Dam chipped away an average of 20 cm of concrete on the surface of the embankment, and although the stability of the embankment was not a problem, repair work was carried out from 1969 to 1970 to place concrete on the worn surface.

Indeed, there is not even moss on the embankment.

Plum blossoms and embankment

It was late March, but the plum blossoms were in bloom.

Discharge warning sign #1

Power generation dams with many gates certainly have the image of frequent releases.

Discharge warning sign No. 2

An orange discharge warning sign is also placed right next to it.

Tree planting in commemoration of Chairman Inoue

Chairman Inoue" refers to Goro Inoue, the first president and chairman of Chubu Electric Power Co.

View of surge tank

We have moved from the right bank to the left bank across the turret bridge. The surge tank stands out even from a distance, but it is still very large when seen up close. Incidentally, the JR Iida line runs right next to the surge tank.

View of hydraulic iron pipe

On the other side of the building, a hydraulic iron pipe can be seen extending toward the power plant building.

Taifu Hydroelectric Power Plant Building

Is this building still the same as when it was built? The small round window at the top gives it an early Showa period look.

Tributaries on the right bank

I didn't pay much attention to it at the time of the photo shoot, but this spot on the right bank seemed to be an excellent spot for the photo.

View of the levee downstream from the left bank

The Taifu Dam has a total of 12 radial gates in the crest. And the color of the gates is a stable Chuden Red.

Control center?

It looks like a management office, but there is also a management office in the back....

Explanatory signboard #1

This is a relatively new explanatory sign. Also, I was actually a little worried about whether we were allowed to freely pass through this area, but these signs seem to indicate that it is okay to visit.

Explanatory signboard No. 2

This is a signboard showing the hydroelectric power stations along the Tenryu River. There are 24 hydroelectric power plants along the main stream and its tributaries.

Taifu Dam Management Station, Chubu Electric Power Co.

This is a newer control center than the control center-like building we saw earlier. But where do you enter from...?

Looking downstream (JR Iida Line on the left)

Further in the back, you will see this kind of scenery. It is rare to find a railroad track right next to a dam like this.

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

The downstream side is a red radial gate, while the dam lake side is black like Kansai Electric Power Co. The original gate was 8.760 m wide and 7.350 m high, but in May 2001, it was replaced by a gate with a net diameter of 8.800 m, a door height of 8.000 m, and a door weight of 24.8 tons.

View of the levee downstream from the left bank

At this location, "Thank you, Taifu Dam.and I remember posting it on Instagram.

View of the conduit from the left bank

The beauty of these smooth curves. It is a beauty created by the collision of artificiality and nature.

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

At any rate, it was a deeply moving visit to the Taifu Dam. Thank you, Taifu Dam.

Taifu Dam Specifications

Other facilities/observations

Parking near the levee would be in an open space on the side of the road.

Accommodations that may be close to Taifu Dam