Building a Movable Dam to Last a Hundred Years! Making Japanese Civil Engineering History with the Ohkozu Sluice-Gate Dam Project

Hydraulic Cylinders at the Heart of the Movable Dam Gates

IHI Corporation was selected to handle the reconstruction of the Ohkozu Sluice-Gate Dam, which has been in service since 1931 and has undergone severe aging.

"The average canal gates are said to have an operating life of about 50 years, but the Ohkozu Sluice-Gate Dam was in service for nearly 80 years and is a symbol of the region's history. The objective for the reconstruction was to exceed that with the creation of a movable dam that would last 100 years." (IHI Corporation point person)

Taking the scenery into account, the reconstructed movable dam would not open vertically, and it would instead adopt a radial gate design that rotates to limit the gates' height. The mechanisms at its heart would be enormous hydraulic cylinders approximately 1 meter in diameter and more than 10 meters long that open and close the gates. No manufacturers make hydraulic cylinders of that size in Japan, so the IHI Corporation point person made a list of several manufacturers mostly based in Europe (where water gate construction technology is advanced) and created an overseas research plan.

An Unprecedented New Challenge for ITO Corporation

ITO Corporation's involvement in the movable dam reconstruction project began by chance, when we heard about it during a visit to IHI to wish them a Happy New Year. Once Mr. Inoue heard about the project, he introduced Eaton Industries (Japan) Ltd., a manufacturing company specializing in hydraulic equipment, to IHI Corporation.

"Eaton, the hydraulics specialist, is a global company with branches all over the world. The hydraulic cylinders are manufactured in a Dutch factory by procuring excellent materials and parts from various European countries. I was confident that they could contribute to IHI Corporation's efforts." (Mr. Inoue)

The IHI point person, who had not initially planned to visit Eaton's Dutch factory, says he was surprised by Mr. Inoue's proposal.

"IHI and ITO Corporation have enjoyed a long business relationship, but I never thought they handled hydraulic cylinders. After hearing Inoue-san's enthusiastic proposal, we decided to add Eaton's factory to the itinerary for our overseas research trip." (IHI Corporation point person)

At the time, this was ITO Corporation's first proposal involving hydraulic cylinders. An order would mean an enormous business deal on a scale of several hundred million yen. It was a big challenge for Mr. Inoue, the point person, as well.

Getting the Order through Sincerity and Commitment, Despite the Lack of a Track Record with Hydraulic Cylinders

IHI Corporation's main priority during the manufacturer selection process was receiving ongoing support after the order. With long-term operation in mind, a support system on par with domestic suppliers was required even for international procurement. When the IHI Corporation point person visited Eaton's Dutch factory along with Mr. Inoue, he said something that happened during the presentation made a strong impression on him.

"The staff from the Dutch factory gave the presentation, but after they finished, a voice suddenly came from a small speaker in the room saying, "Thank you!" in Japanese. It turned out that Eaton's Japanese office had been on the line during the entire presentation. With the time difference, it would have been around 3 a.m. in Japan. I was both surprised and impressed by their commitment." (IHI Corporation point person)

This was something that ITO Corporation and Eaton's Japanese branch had decided on in order to quickly address issues in case of any miscommunications between IHI Corporation and the Dutch factory. Various other steps were taken to make up for the late start entering the market, such as preparing detailed diagrams to match the specifications before the presentation.

"Mr. Inoue always made a point of 'one day response times' to answer my questions or requests by the next day. ITO Corporation didn't have a track record for hydraulic cylinders, but the consistent record of sincerity and the commitment they showed during the Dutch factory visit played a large role in the decision to order from them." (IHI Corporation point person)

Contributing to Japanese Civil Engineering History

After repeated deliberation within IHI Corporation for sourcing the largest and most important part of the project, they accepted the proposal from Eaton and ITO Corporation and placed the order with us. After the order, the IHI Corporation point person and Mr. Inoue visited the Dutch factory multiple times to confirm the manufacturing process, check the quality of the materials procured from various European countries, and oversee the progress. Just before completion, they stayed at the factory and worked side-by-side with the other project members and local technicians for about three weeks to perform the final checks. These efforts paid off as the hydraulic cylinders were successfully delivered and safely installed in the water gates.

Crisis struck, however, before the water gates' field tests were completed. Torrential rains hit Niigata Prefecture and Fukushima Prefecture, including the Shinano River Basin, and the Ohkozu diversion channel also saw rising water levels. If the water gates were not opened, it could have led to significant damage. Despite the lack of testing, the water gates opened flawlessly and damage was minimized. In that moment, the quality of the hydraulic cylinders was proven. Having weathered the crisis, the new sluice-gate dam was completed in November 2011.

"The client (Hokuriku Regional Development Bureau) was very thankful during the heavy rains, and when we temporarily opened the movable dam during a ceremony after it was completed the words of appreciation we received from the local people made all of our hard work worth it." (IHI Corporation point person)

The success of the Ohkozu Sluice-Gate Dam contributed to an increase in IHI Corporation's water gate business performance, and ITO Corporation received a letter of gratitude from IHI Infrastructure Systems. Looking back on this massive project that has been said to be a part of Japan’s civil engineering history, Mr. Inoue reflects:

"The client, the manufacturer, and the trading company that connects them worked together on equal footing to create something big, rather than following a subordinate-superior relationship. We were able to build that kind of ideal relationship for this project, and the fact that we were able to maintain that relationship makes me very happy. That's why we at ITO Corporation will continue to do absolutely everything within our power to help, for maintenance and more." (Inoue)

Written with cooperation from: Hokuriku Regional Development Bureau Shinano River Office
IHI Infrastructure Systems Co., Ltd.