*Yoshinori KODAMA1, Yuuki INOUE2
(1.Fac.of Regional Sciences, Tottori-Univ., 2.Under Graduate, Fac.of Regional Sciences, Tottori-Univ.)
Keywords:potholes, potohole developing processes, line distribution, river incision processes, balloon photoes, The Oshika River, Tottori, Japan
Potholes on the Oshika River bed near Takaganma, Misasa-Town, Tottori, Western Japan were surveyed. Surrounding terrace development revealed that there potholes were formed within 3,600 years. Plan view survey illustrated a line distribution pattern of potholes, resulting from longitudinal vortices generated in flood flows. Longitudinal profiles (Fig.) showed that bottom levels of potholes were close to or towards to those of the present river bed. In general, potholes have a role of effective drilling erosion on a hard bedrock elinimation with few sediment loads in the river incision processes.