FIELD SURVEY ON BAR FORMATION PROCESS AT THE MIDDLE REACH OF TOKORO RIVER

Abstract

The aim of this study is to clarify the influence of the riparian forest to the sediment transport process and bar formation. The Tokoro river is selected for this study because the large amount of fine material from cultivated fields flows into the river during flood. The invasion of trees on bars and the growth of bars with bank erosion are observed at the Tokoro River. The field surveys were conducted at 2009 and 2010 to understand an influence of vegetation to the sediment transport and a relationship between growth of vegetation and bar form. The results of surveys show that the vegetation strongly influences to the fine material transportation during flood and bar shape. In addition, reproducibility of field survey was confirmed by using a numeric calculation method.