The 70th ICHARM R&D Seminar

ICHARM holds Research and Development (R&D) Seminars on an irregular basis to help researchers enhance their skills and stay up-to-date with the latest research findings by inviting domestic and international experts in various fields of water-related disaster management.

Supported by Shinshu University, the 70th seminar, held on May 1, invited two eminent scientists from the University of California, Davis (UC Davis), as speakers: Distinguished Professor M. Levent Kavvas and Dr. ISERI Yoshihiko.

Distinguished Professor Kavvas became a professor of Water Resources Engineering in the Department of Civil and Environmental Engineering at UC Davis in 1990 and is currently a distinguished professor at the university. He is also the Gerald and Lillian Orlob endowed chair professor and the director of the Hydrologic Laboratory and the J. Amorrocho Hydraulic Laboratory at UC Davis. From 1991 to 1996, he conducted joint research on global warming impact prediction with the Public Works Research Institute of the then Ministry of Construction of Japan under the United States-Japan Cooperative Agreement on Science and Technology, and he received the International Award from the Japan Society of Hydrology and Water Resources in 2015.

Dr. Iseri is the manager of the Hydrology Laboratory at UC Davis and specializes in data analysis and numerical computer modeling of integrated atmospheric-hydrologic processes at various scales.

The seminar started with a warm-up talk by Executive Director KOIKE Toshio on the damage caused by water-related disasters in Japan over the past decade and the measures taken to cope with them. He also spoke about characteristic typhoons and rainfall phenomena in Japan and abroad, which was followed by a presentation by Distinguished Professor Kavvas and Dr. Iseri.

As climate change has started causing more intense flooding around the world, traditional methods of estimating extreme rainfall and extreme floods have been under review. They spoke about a related topic entitled "Recent Advances in the Estimation of Extreme Precipitation and Extreme Floods – A Physics-based Perspective.” They first explained four approaches to the estimation of extreme floods: 1) a purely statistical approach to the estimation of extreme floods; 2) the estimation of extreme floods as a result of a rainfall-runoff analysis with input from statistical analysis of extreme precipitation; 3) conventional probable maximum precipitation and probable maximum flood estimation; and 4) the estimation of the maximum flood based on numerical modeling of the critical atmospheric-hydrologic process. Then, they pointed out the problems with the first three methods and discussed in detail their recent research on a physically-based method to maximize precipitation caused by Atmospheric Rivers (ARs)* in considering the maximum precipitation in the West Coast region of the United States. Finally, as a method for estimating the return periods of extreme floods under climate change, they presented the results of integrated atmospheric-hydrologic numerical model simulations of extreme floods, based on an ensemble of GCM hydro-climate projections.

*Atmospheric River (AR): Zonal air current in which large amounts of water vapor are transported through the atmosphere. When atmospheric rivers come ashore, they often bring heavy rainfall.

There were 46 participants, including those who joined online. Their presentation was so inspiring and insightful that it continued beyond its scheduled time as the participants asked many questions about their approach.

ICHARM will continue organizing seminars at various opportunities in the future to update researchers with the latest knowledge and skills on water-related issues across a wide range of perspectives.