Shohoji River Minamizawa No. 14 Stone Dam

Shobojigawa Minamisawa Dam No. 14

At thirty-one metres, Dam No. 14 is the longest in the Minamisawa. It was raised on levelling concrete poured over bedrock, with stone-faced earth banks carried out to either side.

In 1913 a great flood tore through the Shobojigawa valley. In response, Yamagata Prefecture spent the years from 1922 to 1927 building masonry check dams through the ravines above Shimo-Oginoto in Tendo City. The stream drains through the Kuratsugawa into the Mogami River.

About eighty metres below No. 13, and at thirty-one metres the longest dam in the group. It rests on a bed of levelling concrete poured over the rock foundation, and earth banks faced with finely fitted stone flank both ends to add strength.

Why It Matters

In all, the works comprise sixteen dams on the north branch, three on the Tanuki, and ten on the south, joined by gabion structures that steer the current. The idea was not one great wall but many modest ones in series, easing the gradient of a scoured torrent little by little.

The stonework is tanizumi, laid on the diagonal to spread the load, and nerizumi, mortared at the joints so the wall acts as one. Diagonal coursing of this kind resists water and earth pressure and suits a dam set in a fast mountain stream. The downstream face carries a 3-bu batter.

The dams were entered on the register of tangible cultural properties in 2005, valued as a record of early modern sabo engineering and as part of the fabric of the ravine landscape.

Seeing It Today

This is rough country on the edge of Tendo City, with no paved walkways. Visit only after checking the weather and the flow, and keep within safe bounds. Up close you can read the worked faces of the masonry, still holding water after a century, and the moss on the stone.

The dam measures 31 metres along its crest and stands 3.0 metres high. It belongs to the Minamisawa branch and was completed in 1927.