Field trip to Yanba Dam – Day 1

By Liu Chang

Hello everyone, this is Liu Chang writing about our field trip to Yanba Dam from 3^rd September to 4^th September. Just for your information, Yanba Dam is a dam project that is under construction in Naganohara, Agatsuma District, Gunma Prefecture, Japan. The project is currently under construction, with completion slated for 2019. Planning for the dam began in 1947, and it was planned to be completed by 2015. The dam is famous for its construction causing local opposition and ballooning budget.

Trip Map from Google Map: https://maps.google.co.jp/

As we can see from the trip map above, we get together at 8:30 at Ikebukuro station. After taking some more members at Takazaki station, we finally arrived at Hometown Hotel (八ッ場ダムふるさと館). There we have an interesting lunch which is known as Dam Curry (ダムカレー). The name was from its special shape imitating Yanba Dam.

Dam Curry

After having lunch, we find some interesting posters in the hotel which describes the history of construction of Yanba Dam. As it shows below, it has taken a lot of time discussing and communicating with residents, which makes it one of the most time-consuming dams.

Posters about construction history

When we drive to the dam site, we see Yanba Dam from the windows.

Then we get to the Construction Office, where a brief introduction was given. Yanba Dam is built to be a gravity dam. A gravity dam is a dam constructed from concrete or stone masonry and designed to hold back water by primarily using the weight of the material alone to resist the horizontal pressure of water pushing against it. With a height of 116 m, Yanba Dam is the 50^th highest dam in Japan. And it will be designed to apply 11,700 kw electricity with controlling a discharge range from 3,000 to 200 m³/s. A lot of techniques are being used to complete the construction, one of the most impressive is the Cruise RCD (巡航RCD工法). This technique built the stone in the middle first and then cover it with concrete.

Cruise RCD from Iwakigawa Dam Integrated Management Office:  http://www.thr.mlit.go.jp/tugaru/specifi/rcd3.html

Later, we get another chance to go near to the construction site and see the details. From the detailed trip we see that to facilitate the construction, a long rail was built to transport the aggregate. And the rock was taken from a small mountain nearby. After one or multiple times of comminution, the rock was departure due to different size. Because of classification reason, we are not supposed to post any photos.

Then we finally get to the Kusatsu Hotel. Before dinner we have a small group work on three themes about the usage and future of Yanba Dam. Our group chose to discuss about how to arrange some activities of Yanba Dam. Finally, Haga-san gave a fascinating presentation about 1) some boat sightseeing on dam river; 2) project mapping on dam; 3) climbing activity on dam.

Discussion on group work

Finally, we had a relaxing party with members and staffs. The food is so delicious. Although we must stop for a while for digest and some brief introduction about our lab.

Introduction of REEL

One more interesting thing is at the ending of party, Kawasaki-sensei taught us a new style of Banzai. It is some gestures imitating a strong dam trying to lift some heavy water. And by the way, the hot spring is really hot for a foreigner like me!