In light of the frequent occurrence of unprecedented heavy rains and floods attributable to climate change effects, the importance of the “River Basin Disaster Resilience and Sustainability by All” initiative is being emphasized and promoted strongly. This paper proposes a flood damage reduction measure by spillway installation on a riverine levee in a protected area. It can prevent levee breaches to reduce flood waters and flood damage. Moreover, this paper presents results of trial application of the method to an area where severe flood disasters have occurred in recent years. Results show that the measure considerably reduces the flooded area, the days required for drainage, and house flood depths. Results also indicate that the average annual damage to paddy fields in the area can be expected to decrease, although the inundation frequency will increase.

　The Soil Water Index is used to assess risks of sediment-related disasters. This study compared the total storage of a three-stage tank mode with different geologies and examined the rainfall history of total storage. Furthermore, effects of the granite watershed size on the total storage were examined. Total storage was calculated using hourly precipitation data accumulated for 50 years at the Kyoto Local Meteorological Observatory as an input value. From multiple comparisons, the average value of the total storage during rainfall events based on the geology of the large watershed revealed considerable differences between granite and Paleozoic rock, granite and Tertiary rock, volcanic rock and Paleozoic rock, and volcanic rock and Tertiary rock. Total storage tends to increase with the total rainfall or maximum rainfall intensity during a rainfall event, and the rate of increase of the total storage varied in the order of Tertiary < Paleozoic < granite < volcanic rock. The historical ranking of the total storage was similar by geology, as stated in earlier reports. The total storage in the small watershed with granite geology differed considerably from the total storage in the large watershed with granite geology. The total storage in the small watershed tended to increase concomitantly with increasing total rainfall or rainfall intensity, but the historical ranking of the total storage differed depending on the watershed size. More examples of parameter values for the three-stage tank model in series in small watersheds must be accumulated to quantify the total storage of the tank model based on watershed characteristics.

　I describe my research on the development of unsaturated infiltration models to be applied to distributed runoff models. I also introduce my favorite animal, the capybara, and mention the relationship between hydrology and capybaras.