Japan's First Landslide Drainage Well
The Tochigahara Landslide No. 1 Collection Well (栃ヶ原地すべり第一号集水井) is a reinforced-concrete well for draining a landslide of 1955 in Tochigahara, Takayanagi-cho, Kashiwazaki City, Niigata Prefecture, and was registered as a Registered Tangible Cultural Property (structure) on December 5, 2019 (Agency for Cultural Affairs).
The Agency records a reinforced-concrete structure with an area of 13 square metres; registration number 15-0506.
It stands in the hills at the south-eastern edge of Kashiwazaki (Agency for Cultural Affairs), and according to Niigata Prefecture it was completed in December 1955 as the first such well in Japan. A collection well, also called a water catchment well, gathers the groundwater that sets a landslide moving and drains it away.
How the Shaft Drains the Slope
The Tochigahara Landslide No. 1 Collection Well is a reinforced-concrete shaft 4.0 metres across and 18 metres deep. It was sunk to 2 metres below the surface of the bedrock, and horizontal bores fan out from its wall to draw in the surrounding groundwater (Agency for Cultural Affairs).
Records from the time describe the shaft as a body that resists the sliding ground while drainage bores drilled through its wall carry the water off in one place (Niigata Prefecture). The design asks one concrete cylinder to do both jobs.
It was devised by a Niigata prefectural engineer, 湊元光春. According to the prefecture's leaflet, he took his cue from a radial well and a Manchurian well described in a book he read at a library of the occupation forces.
Why It Was Registered
The Agency registered it as a model of design, describing it as the first collection well in Japan, developed from ideas such as the Manchurian well. Niigata Prefecture points out that it became the prototype for the more than 6,000 landslide collection wells now found across the country.
In 2020 the Japan Society of Civil Engineers also selected it as Civil Engineering Heritage, as the first well of its kind and the work that spread the method nationwide.
A Shaft Sunk by Hand
Large machines were not available, and most of the work was done by hand (Niigata Prefecture). Workers dug the soil out from inside the concrete ring so that its own weight carried it down, then cast the next ring on top and repeated the cycle. This self-sinking method is still used to build collection wells today.
When the shaft stopped moving, weights were loaded onto it; when that failed, water was fed around the outside through bores to cut the friction. The top 10 metres or so were dug as an open pit to ease the earth pressure, and local barrel makers lent their skill to the round formwork (Niigata Prefecture). Many people from Tochigahara worked on the site.
At first the well had no concrete lid, and the groundwater it gathered was pumped to a tank and used as household water (Niigata Prefecture).
What to Look For
The shaft is a cylinder 4.0 metres across, and most of its 18-metre depth lies underground. Standing beside it, it is worth keeping in mind how little of the structure shows above the surface.
Two plaques mark the site, one for the registration and one for the Civil Engineering Heritage award (Niigata Prefecture). Water gathered by the No. 3 well, 100 metres to the south-west, runs through a buried pipe into the Tochigahara Landslide No. 1 Collection Well.
Visiting
The Tochigahara Landslide No. 1 Collection Well is a landslide prevention facility owned by Niigata Prefecture. No official information on interior visits or photography was found; the prefecture has run guided visits with local partners such as Takayanagi Elementary School.
Q&A
- When was the Tochigahara Landslide No. 1 Collection Well built?
- It was completed in December 1955 and was the first collection well built in Japan (Niigata Prefecture).
- How big is the Tochigahara Landslide No. 1 Collection Well?
- It is a reinforced-concrete shaft 4.0 metres across and 18 metres deep, sunk 2 metres into the bedrock (Agency for Cultural Affairs).
- Who designed the Tochigahara Landslide No. 1 Collection Well?
- A Niigata prefectural engineer, 湊元光春, who drew on the radial well and the Manchurian well (Niigata Prefecture).
- Can I go inside the Tochigahara Landslide No. 1 Collection Well?
- No official information on interior visits was found. The prefecture has held guided visits with local schools.
- When was the Tochigahara Landslide No. 1 Collection Well registered?
- On December 5, 2019 (Agency for Cultural Affairs).
Basic Information
| Name | Tochigahara Landslide No. 1 Collection Well (栃ヶ原地すべり第一号集水井) |
|---|---|
| Location | 2668-5 Osugi, Tochigahara, Takayanagi-cho, Kashiwazaki City, Niigata Prefecture |
| Designation | Registered Tangible Cultural Property (Structure) |
| Year Designated | Registered 2019/12/05 (Reiwa 1) |
| Quantity | 1 well |
| Dimensions | Reinforced concrete, 13 m², outer diameter 4.0 m, depth 18 m |
| Owner | Niigata Prefecture |
| Public Access | Exterior only (no information on interior access) |
References
- Tochigahara Landslide No. 1 Collection Well (Database of National Cultural Properties, Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/heritage/detail/101/00013065
- Tochigahara Landslide No. 1 Collection Well (Cultural Heritage Online, Japanese)
- https://online.bunka.go.jp/heritages/detail/380244
- Tochigahara Landslide Collection Wells, Registered Tangible Cultural Property and Civil Engineering Heritage (Niigata Prefecture, Japanese)
- https://www.pref.niigata.lg.jp/sec/kashiwazaki_seibi/tochigaharayukei.html
- Tochigahara Landslide Collection Wells, leaflet (Niigata Prefecture, March 2020, Japanese)
- https://www.pref.niigata.lg.jp/uploaded/attachment/228546.pdf
- Civil Engineering Heritage selected in 2020 (Japan Society of Civil Engineers, Japanese)
- https://next.committees.jsce.or.jp/doboku_isan/system/files/2020_tablept.pdf
Last verified: 2026.11.05
