I worked on a dam design team after joining Electric Power Development Co., Ltd.. My area of activities later expanded from hydroelectric power to include thermal power, nuclear power, wind power and other forms of civil engineering. I believe the accumulated technologies of the dam sector form the foundation of modern technology. All civil engineering technologies for a nuclear power plant, such as rock classification and bedrock testing for foundations, earthquake-response analyses of the ground and soil materials using finite element method, and excavating, bedrock cleaning followed by the geological mapping prior to the pouring of foundation concrete for reactor building foundations, apply technologies that were developed for dams. Moreover, head loss estimation for seawater cooling intakes and tunnels use the similar methods for hydroelectric power stations.
I have had involvement in the maintenance and management of existing dams and in ODA (Official development assistance by Japan) dam projects. However, my experience should not be compared with the rich dam-related experience, scholarship, and insight that all of you in JCOLD who came before me possess. Nonetheless, I intend to apply everything I have to the execution of my duties. I humbly request your guidance and support in this endeavor.In recent years, Japan has been afflicted by seemingly annual heavy rain disasters that have brought us great suffering. Examples include torrential rains in western Japan in 2018 and Typhoon Hagibis in 2019. Even now, there are many people who continue to live in difficult circumstances due to these disasters. I would like to extend to them my sincerest wishes for an early end to their plight.
The intensification of weather phenomena is beginning to have a real impact even in our crescent-shaped archipelago. In the case of last year’s Typhoon Hagibis, river levees failed at 140 locations. Thus, it seems that the very nature of weather-caused damage is changing. On the other hand, I am sure that none among you in Japan is unaware of the significant role that Yamba Dam played at that time. While experiencing a strange fate, the dam was completed thanks to the efforts of many who came before us and its stakeholders, and it functioned magnificently during its initial impoundment period. That so many citizens expressed appreciation for it reminds us that dams are extremely important infrastructure in modern society.
At the same time, the many dams that power companies constructed during Japan’s postwar recovery also continue to provide purely domestically-produced renewable energy as important infrastructure and have become accepted by the public. Although hydroelectric power supplies about 8-9% of Japan’s electrical power energy, it is little affected by the weather and thus provides a stable power supply. As the fluctuating power sources of solar power and wind power increase, it is predicted that the role of hydroelectric power in regulating power supply and demand will increase.
I understand that in 1964, when the previous Tokyo Olympic Games were held, there was a record drought that brought a serious water shortage. There are accounts stating that lake bottoms were exposed at Lake Okutama and Murayama Reservoir, and that water supply restrictions of as much as 50% were implemented in Tokyo just before the games began. This year we are experiencing a recorded low rainfall/snowfall winter. It is reported that snowfall is fairly low in the mountainous headwaters of the Tone River, Shinano River, Agano River, and other rivers on which numerous large dams exist. However, the capacity of dam reservoirs that supply Tokyo with water is several times larger than it was in 1964. Here again the value of dams as important infrastructure rises. I believe dams will receive more and more appreciation for their roles in ensuring river basin safety, supplying renewable energy, and supplying irrigation water, drinking water, and industrial water.
Against this backdrop, preparations are underway to use existing water utilization dams to ensure river basin safety. I believe there will be progress in making it possible to conduct efficient reservoir level management at existing facilities with full use of the latest weather forecasting technology and runoff analysis. Before that, however, I would like to receive in-depth discussion on the modification of existing facilities and proceed as projects so that existing dams can fulfill even higher functions. This could involve the improvement of spillways and discharge facilities or raising of dam heights, for example.
Many of Japan’s large dams have stood for nearly sixty years since their construction, and therefore their maintenance and management are important. In the area of sedimentation, the “maintenance and conservation of river environments” was added as an objective under the revised River Act of 1997, and “comprehensive sediment control” is now being promoted as a result. River and river basin environments must be improved. This includes improving the continuity of sediment movement at dam locations. If dams’ sustainability can be enhanced by comprehensive sediment control, a “win-win-win” situation among the environment, flood control, and water utilization will undoubtedly result. With several initiatives already beginning, it is expected that “comprehensive sediment control” will advance through cooperation among river managers, dam owners, and regional communities.
Major earthquakes thought to be highly imminent are also a concern. Most dams were planned and designed in accordance with dam design standards that are based on the pseudo static method. While they are believed to have seismic safety margins, a great deal of research is being on deformation predictions for dam body, foundation rock, and appurtenant structures such as gates in the event of an extreme earthquake. Dams are constantly being monitored using satellites, UAVs, lasers, and microtremor measurement. And steady efforts are continuing to ensure that the effects of displacement before and after earthquakes and changes in vibration characteristics can be confirmed and necessary measures can be taken precisely and swiftly. Artificial intelligence may be an effective tool in analyzing such big data. I therefore intend to pay close attention to the various R&D trends that surround dams.
The International Commission on Large Dams, of which JCOLD is a participant, holds annual meetings as well as triennial Congress. At the technical committees and symposiums there that tackle both “technical innovation” and “sustainability,” Japan’s outstanding engineers engage in passionate discussion with their counterparts from other countries on various themes, including hydrology, structures, materials, numerical analysis, geological features, water resources, sediment control, river environments, climate change, aseismic performance, monitoring, risk management, and river basin management. Moreover, JCOLD sets up a booth presenting Japan’s dam technologies at the meetings’ venues. Due to the hard work of everyone involved, the booth always attracts many visitors and is among the most popular displays.
“Dam tourism” has become highly popular in Japan in recent years. In fact, I heard that the first edition of a guidebook of dam tour titled Dam no Arukikata for which JCOLD was one of the contributors, sold out, leading to the printing of a second edition. Additionally, the closing credits of a recently released dramatic film that was partially filmed at Nagashima Dam and whose main character is a civil engineer included the text “Cooperation provided by the Japan Commission on Large Dams.” Because such activities are a good tool for helping people understand the significance of dams, I would like to continue them.
Although Japan’s dams face numerous challenges associated with advancing age, I believe they will continue playing a major role in the present and future. It is very likely that we are moving away from an age in which we benefit from our predecessors’ efforts in dam construction and toward a time of proper maintenance and management, redevelopment, and reorganization. Furthermore, as our dams grow older, so do our highly skilled dam engineers. I believe the continuation of dam technology is an important assignment of JCOLD.
I will do my utmost to fulfill my duties while seeking guidance, support, and cooperation from a broad range of people and organizations. They include such concerned administrative bodies as the Ministry of Land, Infrastructure, Transport and Tourism, Ministry of Agriculture, Forestry and Fisheries, Ministry of Economy, Trade and Industry, Japan Water Agency, and local governments as well as dam managers in power companies, construction companies and technical consultants, river basin managers, and other stakeholders. They also include JCOLD’s directors, among them former President Joji Yanagawa, Vice President Yoichi Miyamoto, Vice President Yoshiaki Morikita and Vice President TakashiTada, as well as all JCOLD members.
Thank you.
President
Japan Commission on Large Dams