The Uppermost Dam of the Inari River Works
The Kogomedaira Sabo Dam (小米平砂防堰堤) is an erosion control dam on the Inari River of 1931 in Nikko, Nikko City, Tochigi Prefecture, and was registered as a Registered Tangible Cultural Property (structure) on January 31, 2003 (Agency for Cultural Affairs).
The Agency records a gravity concrete dam 34 metres long and 13 metres high; registration number 09-0066.
A Masonry Dam Keyed into a Rocky Gorge
The Kogomedaira Sabo Dam is a gravity dam of mortared masonry on the Inari River, a left-bank tributary of the Daiya River, which rises on Mount Nyoho (Agency for Cultural Affairs). It uses the bedrock of a narrow point in the river and is laid in diagonal masonry. It is the uppermost of the dams built in the Inari River erosion control works of the Home Ministry era.
According to the Nikko Sabo Office, the first government-built erosion control dam in Nikko, Inari River Dam No. 1 of 1919, was dry stone and washed away in a flood about two months after completion. Dam No. 2 of the following year was the first to use rubble concrete, and its success led to the expansion of the works. The Kogomedaira dam was registered on January 31, 2003, together with the Kamagasawa dam and others.
Why It Was Registered
The Agency notes it as one of the key structures of modern erosion control on the Inari River, and registered it for its contribution to the historic landscape.
What to Look For
Look at the diagonal masonry of the dam set into the bedrock of the gorge (Agency for Cultural Affairs).
Visiting
It is owned by the national government (Ministry of Land, Infrastructure, Transport and Tourism) (Agency for Cultural Affairs). No official information on public access was found.
Q&A
- When was the dam built?
- In 1931 (Agency for Cultural Affairs).
- Which river is it on?
- The Inari River, a tributary of the Daiya River.
- How big is it?
- 34 metres long and 13 metres high.
- Where does it sit among the Inari River dams?
- It is the uppermost of the Home Ministry era dams.
- When was the Kogomedaira Sabo Dam registered?
- On January 31, 2003 (Agency for Cultural Affairs).
Basic Information
| Name | Kogomedaira Sabo Dam (小米平砂防堰堤) |
|---|---|
| Location | Nikko, Nikko City, Tochigi Prefecture |
| Designation | Registered Tangible Cultural Property (Structure) |
| Year Designated | Registered 2003/01/31 (Heisei 15) |
| Quantity | 1 structure |
| Dimensions | Gravity concrete dam, 34 m long, 13 m high |
| Owner | Japanese Government (MLIT) |
| Public Access | No official information on access |
References
- Kogomedaira Sabo Dam (Database of National Cultural Properties, Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/heritage/detail/101/00003061
- Registered Tangible Cultural Properties: History of the Sabo Dams (Nikko Sabo Office, MLIT)
- https://www.ktr.mlit.go.jp/nikko/nikko00038.html
Last verified: 2026.10.23