From October 1^st to 4^th, 2018, the INTERPRAEVENT International Symposium 2018 in the Pacific Rim was held in Toyama (Japan). Following Matsumoto (2002), Niigata (2006), and Nara (2014), Japan hosted the 4^th symposium with 492 participants from 27 countries and regions. It was the largest INTERPRAEVENT symposium held in Japan and the third largest INTERPRAEVENT congresses.

Following the opening addresses by Prof. Yoshiharu Ishikawa, Chairperson of the symposium’s local organizing committee, Mr. Kurt Rohner, Chairperson of INTERPRAEVENT, Mr. Jun-ichi Kurihara, Director General of Sabo Department, Ministry of Land, Infrastructure, Transport and Tourism, Dr. Masahiro Kaibori, Chairman of the Japan Society of Erosion Control Engineering, Dr. Hubert Heiss, Ambassador of the Embassy of the Republic of Austria in Japan made their greetings. Finally, Mr.Takakazu Ishii, Governor of Toyama Prefecture, gave his strong message concerning Tateyama Sabo which has protected Toyama for a long time.

In the following days, 10 keynote speeches, 30 oral presentations, 115 poster presentations, the panel discussion with 4 panelists and 1 coordinator and excursions were held with the main theme, "Large scale sediment disasters in orogenic zones and countermeasures". Thirteen exhibitions by sponsors and 31 panels by public sectors were shown. The roll-ups for the 50th anniversary of the Interpraevent, a poster of announcement of the IP2020 Bergen and a poster of the we4DRR for gender equality were also shown.

In the last day, there were comprehensive panel discussions on ways and means to success sustainable development even under the conditions where large scale sediment disasters could occur in orogenic zones by the experts from Italy, Switzerland, Taiwan and Japan.

On the day between the main sessions, one-day excursions (5 courses) took place. In course 1, participants visited the Tateyama Caldera where the Tateyama Sabo Project has been conducted almost for a century. Participants enjoyed riding on trolley trail for Sabo workers. In course 2, participants visited Tateyama Sabo Museum and sabo facilities along the Joganji River, such as Hongu Sabo dam, which has the largest sediment capacity in Japan. In course 3, participants visited sabo and river facilities along the Kurobe River, which is known to be a very rapid and steep river, to the sea coast. In course 4, participants visited the upper stream areas of the Jinzu River where unstable geo-tectonics and thick volcanic ejecta may cause severe sediment yield. Participants went up to the Mt. Hodaka by funicular line. In course 5, participants visited around touristic places in Toyama, such as the world heritage "Gokayama Ainokura Gassho-style Village"(steeply-pitched thatched roofs unique to heavy snowy areas),

The participants had chance to see the present state of sediment-related disaster prevention measures in Japan and experienced the Japanese culture and history through these tours.

In the closing ceremony, following the poster award ceremony, the summary and declaration of the symposium, the Toyama Declaration, was presented by Dr. Yoshiharu Ishikawa with emphasizing that the symposium recognized that the results of the symposium strengthen the contribution to the Sendai Framework 2015-2030 and the outstanding universal value of the Tateyama Sabo which has protected the host city for a century.

The upcoming congress INTERPRAEVENT 2020 in Bergen, Norway was announced by Dr. Aart Verhage, Norwegian Water Resources and Energy Directorate. The closing address was given by Dr. Masao Okamoto, Chairman of the Pacific Rim INTERPRAEVENT Committee of Japan.