Date of interview: Sunday, May 26, 2013

After the Tainai No. 2 Dam and the Oishi Dam, we visited the Iwafune Dam. This is another power plant dam owned by Arakawa Hydroelectric Corporation, which uses the Oishi Dam as a reservoir to generate hydroelectric power at the Oishi Power Station.

Incidentally, if you head from the Oishi Dam, you will find the Takanosu Dam before the Iwafune Dam, but for some reason I completely missed it at the time.

Downstream view of the levee from the left bank

The water was being discharged through one of the four roller gates.

Shooting over the fence

Unfortunately, however, it is off-limits, as is typical of dams owned by electric power companies. To the right is the spare gate door body used during maintenance.

View of the downstream face of the dike and the water intake from the left bank

On the left is the dike and on the right is the gate pier at the water intake. There are four roller gates on the embankment, but there seems to be another gate closest to the left bank. Is it a gate for river maintenance?

Water taken from the intake on the right is pumped to the Iwafune Power Plant located just downstream (in the foreground in the photo), where it produces up to 11,500 kW of electricity.

View of the downstream face of the dike and the water intake from the left bank

View of the top edge from the left bank

The gate pier is also quite high.

View of the intake gate from the left bank

The door is fully open, but can you see that the door body is quite large?

View of the upstream face of the dike and the water intake from upstream

It can be seen from upstream, but it may be a little difficult to see due to overgrown vegetation.

Iwafune Dam discharge animation

The discharge scene of the Iwafune Dam is summarized in the video. Please take a look at it as well.

Iwafune Dam Specifications

Location	Katakai, Sekikawa-mura, Iwafune-gun, Niigata
River Name	Arakawa River System Arakawa
Objective	P(Power generation)
Model	G(gravity-fed concrete dam)
Bank height	30.2m
Bank length	92.6m
Dam volume	27,000 m3
Watershed Area	766km2
Reservoir area	67 ha
Total storage capacity	5,875,000 m3
Effective water storage capacity	1,072,000 m3
Dam operator	Arakawa Hydroelectric Power Co.
Main body constructor	Kajima Construction
Year of launch	1960.
Year Completed	1961
Name of Dam Lake	-