EFFECTS OF SUBMERGED LONGITUDINAL DIKES CONSTRUCTED IN EDO PERIOD ON RIVER CHANNEL IN MIDDLE REGION OF MIDORIKAWA RIVER

Abstract

In Kumamoto Prefecture, there are many flood protection and water utilization works as diversion structures, levees and groins made of stones which were constructed by Kiyomasa Kato as a feudal lord in the early Edo era. However, most of the works have not been clarified with actual evidence as to how they play a role in flood protection water utilization. In this paper, Shizumidomo called in Japanese, which was constructed at confluence of Midorikawa river and Samatagawa one as longitudinal dike, has been investigated from the viewpoint of historical river regulation methods by applying a hydraulic model. The model scale was 1/200. In addition, Kutsuwadomo and Hane in Midorikawa river basin as open levee were discussed by excavation of levees and old map in Edo era.