For the water management of the Yabe River, which runs in the southern part of Fukuoka Prefecture, Japan, flood damages on structure of river since the Taisho era and agricultural water utilization were surveyed from historical materials. Length of main stream is 58.3km and catchment area is 618km^2 . The area of paddy irrigated in the basin is about 15,OOOha. The Yabe River is disadvantageous for use of water resources because of large coefficient of river regime, which denotes the stability of a flow. As discussed in previous our paper, floods have caused damage to the basin because of irregular flow that is characteristic in an alluvial fan. Regarding reports on flood occurred in 1953, destructions of bank were caused by water leak, defect of bank and over flow. Defects were the sharp inclination of bank surface, improper soil for bank, and incomplete compaction of soil. Over flow occurred at the point where the height of bank was relative lower and water level rose due to driftwood caught on a bridge. Great efforts has been paid for dividing river water because the Yabe River was the only source of irrigation water for the large paddy field in the middle and lower basin. River water was divided by a rule depending on group of water utilization and by customs at a barrage, and there had been struggles between two clans, which lied on opposite bank of the river. Problems for water utilization of the river have been complicated although they have been solved after the completion of the dam constructed in the upper stream.
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