What Is Bannai River No. 13 Sabo Dam?

Bannai River No. 13 Sabo Dam (万内川十三号堰堤, Bannaigawa Jūsangō Entei) is a concrete gravity sabo dam built around 1934 on the Bannai River in Nishinoya, Myoko City, Niigata Prefecture, and was registered as a Registered Tangible Cultural Property on March 18, 2003.

A sabo dam is a check dam that traps sediment in a mountain stream. Bannai River No. 13 Sabo Dam is 35 meters long at the crest and 5.9 meters high, the tallest of the registered Bannai dams, with revetments on both banks downstream. Its downstream face has a batter of 1:0.2 and its upstream face 1:0.3, and it is built as a gravity dam of mortared stone.

It was added above the Taisho-era series in the middle reach after a flood in 1933, a sign that the project begun in 1921 was pushed further upstream when new disasters struck in the Showa era.

Why It Was Registered

The dam was registered as a structure contributing to the historic landscape of the country. The Agency for Cultural Affairs points to the spillway notch set in the center of Bannai River No. 13 Sabo Dam, which gives it an almost symmetrical form, and to the well-preserved Tanizumi revetments on both banks below it.

A Japan Society of Civil Engineers nomination document classes No. 3 through No. 12 as dry-stone gravity dams of local stone (strengthened with mortar in the early Showa era) and No. 13 and No. 14 as concrete gravity dams faced in mortared stone. Within a single valley, the Bannai dams show construction shifting from Taisho dry stone to Showa mortar and concrete, and Bannai River No. 13 Sabo Dam stands for that later phase.

What to Look For

At 5.9 meters, No. 13 is nearly twice the height of several of the Taisho dams downstream. Walk up through the reach of low stepped dams and then stand before this one, and you can sense the heavier stance of a dam built in response to the 1933 flood.

From the front the dam is balanced on its central notch. Compare it with No. 14 just upstream, built around the same time: both share a symmetrical plan, but their cross-sections differ, and No. 14 has a row of arched drain openings across its front.

Look, too, at the tanizumi revetments on both banks below the dam. Their angled stones, switching direction course by course, give a different texture from the mortared masonry of the dam itself.

How to Visit

Bannai River No. 13 Sabo Dam stands above the Taisho-era series, beyond No. 12. The upper dams are reached by following the riverside path up from Bannai River Sabo Park. Check the on-site map for how far the maintained path runs, and do not continue onto the riverbed or slopes where it ends.

Bannai River No. 13 Sabo Dam stands in the open and can be viewed freely from the path; neither the prefecture nor the city lists any restriction on photography. It is a working sabo structure, so stay off the crest and the spillway notch, and keep back from the water after heavy rain. Opening season and directions to Bannai River Sabo Park are covered on the Bannai River Sabo Facilities page.

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Q&A

QWhen and why was Bannai River No. 13 Sabo Dam built?
AIt was built around 1934, above the earlier Taisho-era dams, in response to a flood in 1933.
QWhy is Bannai River No. 13 Sabo Dam a Registered Tangible Cultural Property?
AIt was registered on March 18, 2003, as a structure contributing to the historic landscape. Its near-symmetrical form around a central notch and the well-preserved tanizumi revetments on both banks are cited.
QHow big is Bannai River No. 13 Sabo Dam?
AIt is 35 meters long at the crest and 5.9 meters high, the tallest of the registered dams on the Bannai River.
QCan I visit Bannai River No. 13 Sabo Dam, and is there a fee?
AYes. It is outdoors and can be seen freely from the path. Bannai River Sabo Park is open from April to November and there is no charge.
QWhere is Bannai River No. 13 Sabo Dam?
ABannai River No. Directions to Bannai River Sabo Park are on the Bannai River Sabo Facilities page.

Basic Information

NameBannai River No. 13 Sabo Dam (万内川十三号堰堤)
LocationNishinoya, Myoko City, Niigata Prefecture
DesignationRegistered Tangible Cultural Property (Structure), Registration No. 15-0153
Year DesignatedRegistered 2003/3/18 (Heisei 15)
Quantity1 structure
DimensionsCrest length 35 meters, height 5.9 meters
OwnerNiigata Prefecture
Public AccessOutdoors and freely viewable; Bannai River Sabo Park is open April to November, free of charge

References

Agency for Cultural Affairs, Database of National Cultural Properties: 万内川十三号堰堤
https://kunishitei.bunka.go.jp/bsys/maindetails/101/00003220
Cultural Heritage Online: Bannai River No. 13 Sabo Dam
https://bunka.nii.ac.jp/heritages/detail/187950
Niigata Prefecture: Bannai River stone sabo dams (Registered Tangible Cultural Properties)
https://www.pref.niigata.lg.jp/sec/jouetsu_sabou/bunkazai-bannai.html
JSCE Kanto Branch: Bannai River sabo dams and Hikagesawa ground sills
https://www.jsce.or.jp/branch/kanto/04_isan/h29/h29_8.html

Last verified: 2026.09.24