A STUDY ON BEACH SEDIMENT AT ENO-SHIMA AND KAMAKURA

抄録

The paper presents the preliminary results of investigation on the movement of coastal sediment and its effects on beach erosion at Eno-Shima and Kamakura, summer resorts on the Pacific coast of Japan. This study constitutes a part of a series of extensive field survey program carried out by the authors and the engineers of the Hydrographic Office and the Transportation Technical Research Institute under auspices of the Kanagawa Prefectural Government over the period from September, 1956, to February, 1957.
One of the main difficulties encountered was the lack of records on the actual progress of erosion. No previous investigation had been made on winds, waves, littoral currents, variation of beach and nearshore profiles, except for recent geologic, surveys by the Hydrographic Office [1 and 2]. As a result of the limited assigned period of investigation the influence of the summer, typhoon storms on the characteristics of beach sediment was left untouched. The eventual cause of erosion along these beaches could only be detected on the basis of more extensive, continued investigation.
Neverthless some preliminary conclusions have been attained on the fundamental nature of the persisting erosion as affected by the characteristics of winds, waves, geographical situations, topographies, littoral currents, and consequent movement of beach sediment. A further investigation on littoral currents, waves, and beach profiles has been in progress on the same beaches since June, 1957.