Stone-Lined Channels Back to the Sato River
The Gami Power Plant Outfall and Spillway (賀美発電所放水路及び余水路) are the water channels of a hydroelectric station built in 1919 in Kamifukaogi-cho, Hitachiota City, Ibaraki Prefecture, and were registered as a Registered Tangible Cultural Property (structure) on November 8, 2004. They are owned by the Tokyo Electric Generation Company.
The Agency for Cultural Affairs records them as concrete channels 299 m in total length with a reinforced concrete bridge; the registration number is 08-0141.
Why They Were Registered
The Gami Power Plant Outfall and Spillway were registered as structures that contribute to the historic landscape of the country. According to the Agency for Cultural Affairs, they consist of the outfall channel running from a segmental-arch outlet east of the powerhouse to the Sato River, and a spillway carrying overflow from the head tank to join it.
The channel walls are finely laid in stone set diagonally in the tanizumi pattern, battered at a slope of about 3 in 10. Near the river, a segmental-arch reinforced concrete service bridge crosses the channel, its side walls faced in horizontally coursed stone (Agency for Cultural Affairs).
What to Look For
Look for the segmental-arch outlet on the east side of the powerhouse and the stone-lined channel leading from it to the Sato River. The diagonally set stones of the tanizumi walls line both sides in neat rows.
Near the river, the service bridge is a reinforced concrete segmental arch with walls of horizontally coursed nunozumi stonework (Agency for Cultural Affairs). Compare the two styles of masonry.
Visiting the Gami Power Plant Outfall and Spillway
The Gami Power Plant Outfall and Spillway are part of a working power station. No official information on viewing points or parking could be confirmed. Do not enter the facility, and follow posted guidance when viewing from outside. The Gami Power Plant page covers the station as a whole.
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Q&A
- When were the Gami Power Plant Outfall and Spillway built?
- In 1919.
- When were they registered as a cultural property?
- On November 8, 2004.
- What is the difference between the outfall and the spillway?
- The outfall returns water from the powerhouse outlet to the Sato River; the spillway carries overflow from the head tank to join the outfall.
- How long are the channels?
- 299 m in total.
- Can you visit them?
- They are part of a working power station; follow posted guidance when viewing from outside.
Basic Information
| Name | Gami Power Plant Outfall and Spillway (賀美発電所放水路及び余水路) |
|---|---|
| Location | Kamifukaogi-cho, Hitachiota City, Ibaraki Prefecture |
| Designation | Registered Tangible Cultural Property (Structure) |
| Year Designated | Registered 2004/11/8 (Heisei 16) |
| Quantity | 1 site |
| Dimensions | Concrete, 299 m long, with reinforced concrete bridge |
| Owner | Tokyo Electric Generation Company |
| Public Access | Part of a working power station |
References
- Gami Power Plant Outfall and Spillway (Database of National Cultural Properties, Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/heritage/detail/101/00004311
- Cultural properties (Tokyo Electric Generation Company)
- https://tokyohatsuden.co.jp/csr/cultural_property/
- Sato River hydroelectric plants (JSCE Civil Engineering Heritage)
- https://committees.jsce.or.jp/heritage/node/956
Last verified: 2026.10.06
