Arakawa Seventh Dam

What the Arakawa Seventh Dam Is

The Arakawa Seventh Dam (荒川第七堰堤, Arakawa Dai-nana Entei) is a gravity-type concrete sabo dam built in 1951 on the Arakawa River at Yasumiba, Tsuchiyu Onsen-cho, in Fukushima City, Fukushima Prefecture, and registered as a Registered Tangible Cultural Property (structure) of Japan on March 7, 2008. It is 69 meters long and 12 meters high, and Fukushima City lists the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) as the owner.

One of the 15 registered Arakawa River Sabo Dams, it sits about 200 meters above Kawakami First Dam and about 400 meters below the Arakawa Eighth Dam, in the middle of a short run of three closely spaced dams. It was registered as a Registered Tangible Cultural Property in 2008 under number 07-0090.

A Plaque on the Right Wing

Set into the top of the dam's right wing is an inscribed plaque. According to the Agency for Cultural Affairs, it gives three things: the dam's name, the body that built it and the year of construction, all cut into the stone in incised lettering.

The wings are the raised shoulders on either side of the spillway notch in the middle of a dam. They stay above water in most floods, which presumably made them the natural place for a plaque. "Right" follows the river convention: it is the right-hand side when you face downstream, so the right bank.

Of the Agency's descriptions for all 15 registered dams, only the one for the Arakawa Seventh Dam mentions a plaque. The structure carries its own record of who built it and when.

How the Arakawa Seventh Dam Is Built

The section follows the group's standard slopes, 1 to 0.45 on the upstream face and 1 to 0.2 downstream. The upstream face is cobble masonry of rounded river stones and the downstream face is Nunozumi, coursed stone with level joints. That pairing repeats the Arakawa Sixth Dam, completed the year before.

The Seventh also belongs to a set of three built in sequence with Kawakami First Dam (1946) below it and the Arakawa Eighth Dam (1952) above. In its description of the Eighth, the Agency explains that the three were built one after another to ease the gradient of the streambed and steady its banks. Three dams in roughly 600 meters turn the slope of the bed into a series of steps.

Seeing the Arakawa Seventh Dam

The Arakawa Seventh Dam is a working sabo structure. Viewing is free from the surrounding ground; you cannot walk on the dam or enter the riverbed.

The plaque is the main thing to find. Facing the dam from downstream, the right bank is on your left, so look to the top of the left-hand wing as you see it.

The dam lies in the hills above Tsuchiyu Onsen, and you can compare it with Kawakami First Dam and the Arakawa Eighth Dam over a short distance. Paths narrow as you go upstream, so wear sturdy shoes, and stay out of the valley after rain. Directions are on the Arakawa River Sabo Dams page.