Investigation and verification aiming at establishing a method for evaluating the structural stability of "agricultural reservoirs"

Abstract

Japan is home to more than 170,000 agricultural irrigation reservoirs, many of which were constructed as many as 400 years ago. With many of these structures built in times with less knowledge of materials and modern engineering methods, there is a great variability in both quality and structural integrity of these reservoirs. These small earth dams are managed by a variety of autonomous bodies and many are also privately owned. This means that not only are many of these reservoirs ancient, but they also vary considerably in construction and condition. Due to Japan’s location on top of four tectonic plates, as many as 1,500 earthquakes occur in the island nation each year. Earthquakes and other natural disasters have a profound impact on all types of structures, from buildings and homes to roads and agricultural structures and these must be assessed and built to cope with these phenomena. The death of a little girl in the July 2018 Flood in western Japan highlighted the importance of structural safety of reservoirs to Professor Hiroshi Mori, from the Department of Agricultural and Environmental Engineering at Hirosaki University in Japan. Mori’s work is focused on the development of a sounding method of surveying the embankments of agricultural irrigation reservoirs as well as a method of estimating the safety of these structures. It is necessary to carry out these safety evaluations on both existing and abolished reservoirs to ensure their ongoing safety as well as assess them for any repairs that might be required.