Abstract
In Kumamoto Prefecture, there were many flood protection works such as diversion structures, levees and groynes made of stones which were constructed by Kiyomasa Kato as a feudal lord in the early Edo era. However, most works have not been clarified with actual proof as to how they play a role in flood protection. In this paper, Kutsuwa Domo commonly employed by Kiyomasa, which entails the widening a river at the confluence or rushing points to weaken floods, was investigated from the viewpoint of historical river regulation methods by applying a hydraulic model to a Kutsuwa domo located at Shimada district in the Hamado river. The model scale was 1/150. The results of this paper showed that Kutsuwa domo was originally created by Kiyomasa, different from Kasumi bank (open levee) and effective works for floods exceeding the design limit.
