In early age of Edo period, there were extensive irrigation and flood protection works by use of diversion structures, levees, weirs and groynes made of stones in Kumamoto Prefecture which weredirected by Kiyomasa Katou as a feudal lord. Some of the historical monuments have been still working properly. In this paper, the structural features of weirs, levees and irrigation channels constructed by Kiyomasa Katou were investigated from a viewpoint of traditional river regulation methods. The results showed that the monuments have multiple functions to control flood discharge, water level and sedimentation.
