Abstract
A rainy front brought about the heavy rainfall into watershed of the Sendai River which run through a south part of the Kyushu Island, July 2006. It led to a serious disaster regionally called Hokusatsu heavy rain disaster. A rapid rising of river water level was observed at the Miyanojo observatory station near the Torai district in the heavy rain disaster. In this study, rainfall-runoff analyses were carried out to understand effects of space-time distribution of rainfall on rising rate of river water level in the downstream area of the Tsuruda Dam. As the results, it is implied that not only a high intensity of rain but also rainfall events before/after the high intensity rain affected the rapid rising of river water level at Miyanojo. It is considered that the rising rate of water level as rapid as that at Miyanojo in the heavy rain disaster may occur in other segments of the Sendai River.