Field Observation of Movement of Granite Gravel on Oharai-Isohama Coast

Abstract

On the Oharai-Isohama coast, 1×10⁴ m³ of gravel and 2.5×10³ m³ of fine sand were nourished in April and May 2012 as a measure against beach erosion. Simultaneously tracer test was carried out using 100 m3 of granite gravel with a diameter of 20 cm, which was not deposited on the original beach. Granite gravel was placed on the shoreline, and subsequent movement was measured using GPS along with the measurement of the diameter of the gravel. It was found that gravel was transported northward and deposited on the shoreline.