BEACH CHANGES IN AN EXTENSIVE AREA BETWEEN OTSU FISHING PORT AND TAKADO POINT IN NORTHERN IBARAKI PREFECTURE

Abstract

 Beach changes along a sandy beach of 13.5 km length between Otsu fishing port and Takado Point in northern Ibaraki Prefecture were investigated based on aerial photographs. A long offshore breakwater was constructed at Otsu fishing port at the north end of this area, forming a large wave-shelter zone west of the breakwater and causing deposition of sand. In contrast, sandy beach in front of the seawall was eroded in the southern part of the area, causing instability of the seawall. It was found that even though the coastline length is long as 13.5 km, topographic changes due to the formation of a wave-shelter zone reach the vicinity of Takado Point at the south end of the study area.