2008 Volume 52 Pages 1087-1092
The purpose of this study is to demonstrate the process of deposition and influence of human and natural impacts to sediment in Imazu tidal flat. In this study, various impacts on Imazu tidal flat were examined with the use of topographic, aerial photographs, rainfall record. Then, analysis of core sample's gradation, ignition loss, 137Cs and 210Pb was studied to clarify the age of sedimentation and historical change of environment of sediment. The results were as follows. The urban development around Imazu tidal flat has had worse influences on the sedimentary environment. The sedimentation rate of Imazu tidal flat was calculated 0.47-1.12cm/y since 1963, and in 1954-1963 was 1.56-3.56cm/y by the analysis of core samples. It was calculated that 5640-13440m3 sediment was discharged from catchment area annually, and 47520-333720m3 sediment flowed in Imazu tidal flat in 1953 by these results. It was assumed that this was caused by the flood in 1953.
