| Budget Amount *help |
¥18,720,000 (Direct Cost: ¥14,400,000、Indirect Cost: ¥4,320,000)
Fiscal Year 2013: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2012: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2011: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2010: ¥13,130,000 (Direct Cost: ¥10,100,000、Indirect Cost: ¥3,030,000)
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| Research Abstract |
This study investigated the formation and depositional history of oxbow lakes based on the analysis of core sediments obtained from the oxbow lakes and the floodplain of the Ishikari River, northern Japan, and discussed the environmental change of the lower reaches of the river. The main results of this study are shown below. (1) We proposed the conventional method to make a bathymetric map of oxbow lakes by using fish finding sonar and GPS. (2) Bottom sediments of the lakes are mainly composed of fine-grained mud and water chestnuts prosper in shallow water especially during summer season. (3) The lakes formed during the last several hundred years and have been filled rapidly. (4) The change of the sediment grain size may be correlated with the change of summer precipitation. (5) Evolution of the floodplain has been influenced strongly by the rate of postglacial sea-level change.
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