Akatan Sabo Dams

What the Akatan Sabo Dams Are

The Akatan Sabo Dams (アカタン砂防堰堤群, Akatan Sabō Enteigun) are nine erosion-control dams built from 1900 on the Akatani River in Furuki, Minamiechizen, Fukui Prefecture, as the prefecture's first sediment-control project, and all nine were registered together as Registered Tangible Cultural Property on July 23, 2004.

"Sabo" is the Japanese engineering term for controlling the soil, gravel and boulders that mountain streams carry downhill in heavy rain, and it has passed into international usage. The Akatani is a small side stream of the Takura River, itself a tributary of the Hino. Locals call it simply "Akatan," and the name stuck to the dams. Seven are built of stacked stone; two are embankments of rammed earth. They are spaced out along the valley, from the Obira Mizuya Upper Dam at the top to Dam No. 9 at the bottom.

The national database of the Agency for Cultural Affairs dates all nine to the fourth decade of the Meiji era (1897 to 1906) and numbers them 18-0027 through 18-0035 in order from upstream. Each was registered under the same criterion: a structure that contributes to the historic landscape of the country.

Built After a Run of Disasters

Heavy rains between 1895 and 1897 tore through the upper Akatani, around an area known as Obira (大平, Ōbira), and set off landslides that choked the valley. Fukui Prefecture responded by making the stream the site of its first sabo program, breaking ground in the fiscal year that began in 1900. The prefecture's own leaflet gives the construction period as 1900 to 1906.

Fukui had no sabo specialists of its own at the time. According to the prefectural account, sabo specialists and skilled stonemasons were brought over from neighboring Gifu Prefecture, and between 200 and 300 people from the village and beyond worked on the site each day. Women are said to have built the earth dams by senbon-tsuki, a method in which a crowd rams the fill down with poles, while men handled the stonework. There was no heavy machinery; the stone came from the riverbed and the surrounding rock.

Nine Dams Working as One System

The Akatan Sabo Dams were laid out with the whole valley in mind rather than as separate structures. Upstream, they hold the streambed and banks in place; downstream, they trap the sediment that still gets through. The five Obira dams sit within roughly 500 meters of one another near the head of the valley. Below them come the Matsugahana and Oku-no-Higashi dams, and then, where the valley widens, two big earth dams. The largest, Dam No. 8, runs 112 meters across and stands 11 meters high.

All the stone dams are dry-stone work, laid without mortar, and many rest directly on exposed bedrock. Several push their spillway notch against one side of the valley and add a stone training wall at a right angle, steering floodwater onto solid rock. The Japan Civil Engineering Consultants Association notes that smaller dams and channel works survive farther upstream as well.

Forgotten, Then Found Again

Once finished, the dams did their job quietly for decades, and as trees grew over them they slipped out of local memory. A feature by the Minamiechizen tourism association describes how residents, working from the recollections of village elders, spent about seven years tracking down all nine, then felled trees and cut back brush until the stonework could be seen as it was built. Their group, the Takuragawa to Kurashi no Kai (Takura River and Livelihood Association), was founded in 1998.

At Retreat Takura, a community activity center downstream on the Akatani, the association runs a small exhibit it calls the Akatan Sabo Eco-Museum, with maps of the dams and records of its work. A stone marker and an information board at the trailhead note the dams' status as Registered Tangible Cultural Property.

Getting There and Walking the Trail

A car is the practical way to reach the Akatan Sabo Dams. From Imajo Interchange on the Hokuriku Expressway, take Route 365 south for about 2 kilometers, turn left at the Hiuchi intersection, and follow Route 476 east for about 6 kilometers. From Nanjo Smart Interchange the drive takes about 20 minutes. The nearest station is Imajo on the Hapi-Line Fukui, roughly 10 kilometers away by road.

Park at Retreat Takura. A walking trail of about 3.5 kilometers starts beside the information board and follows the Akatani upstream past all nine dams. Fukui Prefecture puts the round trip from Retreat Takura to the Obira Mizuya Upper Dam, the highest of the group, at about 2 hours. Cars can drive as far as Dam No. 8.

The dams can be visited from April through November; the trail is closed to visitors in the snowy winter months. Expect steps and slopes, wear sturdy shoes, and view the dams from safe ground rather than climbing on them. Partway along the forest road a wire-mesh gate keeps out wild animals; close it behind you. Guided walks with a storyteller from the local association can be arranged in advance through Retreat Takura (phone 0778-45-1310).