抄録
In recent years, heavy rainfall over 50 mm/h and heavy rainfall concentrated into short time span on the order of 10 min have occurred more frequently in Japan, owing to the effects of phenomena such as climate change. This report describes the result of simulation using simulated drainage zones to examine the specific countermeasures that are suitable for each district. We consider it important to increase the inundation control quantity across the entire area (1) using peak reduction storage infrastructure for areas at the branch line drainage zone level and for short-duration heavy rainfall, and (2) using a combination of inundation countermeasures including downflow infrastructure and storage infrastructure to upgrade the entire runoff area for heavy rainfall that continues for a long duration in areas at the main line drainage zone level. This paper also reports on progress in collecting case examples on facilities that utilized stormwater in each local government. These case examples are being collected as a resource for promoting the improvement of stormwater storage infrastructure and the effective utilization of water resources in the future.