Date of interview: Wednesday, November 19, 2014
On this day, after visiting the Miyama Dam, the main part of the tour, via the Shiobara Dam (glimpse only) and Itamuro Dam (entrance only), the other main dam we visited was the Numappara Dam. This is also the upper reservoir of the Electric Power Development Co.,Ltd. Numappara Power Station, where pumped storage power generation is carried out. (The Miyama Dam is the lower reservoir.)
The Numappara Dam is normally off-limits to visitors, and the only way to view it is from the walking trail in the Numappara Marsh, but on this day, we were given special permission to visit the dam.
Incidentally, the Emperor Showa composed a poem entitled "Slope" on the theme "Saka" at the beginning of the 1976 Poetry Reading, in which he said, "If you climb up the slope in a forest of fragrant woods, you will see a broad dam.
Looking south from the south top edge
Since Numappara Dam does not have a flood discharge, I do not think there is a concept of downstream/upstream, so I would like to indicate this in terms of direction. A dam is always a fail-safe feature.Flood dischargeI was aware that there was an excess water discharge, but does this Numappara Dam have no flood discharge because the power generation is sufficient to discharge the water into the Miyama Dam?
Looking north from the south top edge
It was a windy day, and the water in the regulating pond was filled with white waves. The top elevation was about 1,240 m, and it felt quite cold because of the high altitude and the time, which was after 4:00 p.m.
Unlike ordinary dams, the Numappara Dam was constructed by digging into the earth and partially raising it. This creates a unique sight of a reservoir on top of a mountain. Moreover, it is a rare asphalt-facing fill dam.
Looking east from the south top edge
It was November, but snow was already visible here and there.
parapet
The top edge is not similar to a railing, and a parapet has been constructed.
Looking south from the north top edge
I doubt if it's really north to south because my memory is a bit fuzzy, but sorry if I'm wrong.
View of Numappara Marsh from the north top edge
To the north of the Numappara Dam is an expanse of marshland. It is open for walking, and the Numappara Dam is generally viewed from here and from the high ground to the west. The Emperor Showa also visited the site several times. (I think that is why he composed the poem at the opening ceremony of the poetry festival.)
Looking south from the north top edge with part of his car
The high altitude at dusk and the proximity of clouds create a fantastic landscape. This kind of scenery can only be seen here.
Looking west from the north top edge
I am grateful for the opportunity to visit a good dam at the end of the day. I had planned to leave for Fukushima and return home via Ibaraki, but I had to return to my home in a hurry, so I had to run back to the hotel.
Numappara Dam Specifications
Location | Nasushiobara City, Tochigi Prefecture |
River Name | Naka River System Naka River |
Objective | P(Power generation) |
Model | FA (Asphalt Facing Fill Dam) |
Bank height | 38m |
Bank length | 1,597m |
Dam volume | 1,260,000 m3 |
Watershed Area | -km2 |
Reservoir area | 18 ha |
Total storage capacity | 4,336,000 m3 |
Effective water storage capacity | 4,220,000 m3 |
Dam operator | Power Development Co. |
Main body constructor | Kajima Construction |
Year of launch | 1969. |
Year Completed | 1973 |
Name of Dam Lake | Lake Numahara |
Other facilities/observations
The parking lot and restrooms are in Numappara Park. The observatory seems to be a little elevated in some places, but it is not clear whether it can be called an observatory or not, so it is rated as a minus.
Parking lot | ○ |
Toilet | ○ |
Park | × |
PR Exhibition Hall | ○○ (Forest Power Generation Ohanashi Kan) |
Fishing | × |
Viewing platform | △ |
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