2014 年 5 巻 1 号 p. 65-71
The study attempts to clarify the functions of oxbow lakes in rural irrigation systems. The status of oxbow lakes was briefly investigated through interviews with town officials and land improvement agencies. It is clear that even though canals have been constructed in the area, oxbow lakes in the Ishikari River basin are utilized as primary and auxiliary irrigation resources and as reservoirs for circulating irrigation systems. In the Urausu region, 14% of the irrigation water resource comes from oxbow lakes. The percentage of drainage into the oxbow lakes is 72.0% during the puddling period and 64.6% during the normal period. The percentage of water recycled through the oxbow lakes is 76.3% during the puddling period and 66.4% during the normal period. Furthermore, all water used in circulating irrigation is obtained from the oxbow lake in the region around Karisatonuma. This reduces the amount of water taken from the river. This suggests that rural resources, such as oxbow lakes, can continue to be used as a component of regional irrigation systems. This information may be beneficial as a reference for cost-effective development of rural irrigation systems in developing countries.
