A STUDY ON RELATIONSHIP BETWEEN SEDIMENTATION CAUSED BY INUNDATION AND DRYING PHENOMENA IN KUSHIRO WETLAND

The Kushiro Wetland, one of the precious wetlands in Japan, is located in the east of Hokkaido, downstream of the Kushiro basin. A number of meandering channels were retained without manipulation. Nowadays, the Kushiro wetland is faced with many problems. The drying phenomena impact many kinds of animals and plants, especially in reducing the number of habitats of precious spieces. The phenomena stem from sediment deposition on the surface layer due to the inundation and the decrease of the capacity of preserving water. The wetland acts as a vast area, and allows overflowing freely during the flood period. It is an important factor for the drying phenomena of the wetland. The purpose of this study is to develop a numerical model to simulate the flooding of the Kushiro wetland, and to investigate the relation between the accumulation of suspended sediment and the drying phenomena with both of whole and limited areas in the wetland.