Investigation of Beach Deformation Around Artificial Headlands to Prevent Beach Erosion on Misawa Coast, Japan

Mikio Sasaki, and Takahiro Takeuchi

Hachinohe Institute of Technology, Japan

Abstract: The present study shows the effects of the artificial headlands constructed on a coast to prevent beach erosion caused by longshore sand drift. There was a beautiful and long sandy beach in Misawa city, Aomori prefecture, Japan. However, after a fishery port was constructed in the sandy beach in 1971, severe beach erosion has occurred on the Misawa coast. Some sandy beaches of 500 m width disappeared along the coast. In response, Aomori Prefecture constructed artificial headlands along suitable lengths of the coast between 1991 and 2020. The aim of the construction for the artificial headlands is to prevent beach erosion and to create a stable state on the coasts between the artificial headlands. Field observations of the shoreline by authors using a GPS measurement machine have been carried out once a month on the Misawa Coast since 1992. The geographical bottom changes in the long term have been obtained by using the shoreline observations. Using the results, the beach deformation after the construction of the artificial headlands is shown. The effect of the countermeasures using the artificial headlands for beach erosion is also shown in the present paper. Beach erosion is no longer occurring on the north Misawa coast as artificial headlands are creating stable beaches. The effects of the countermeasures using the group of the artificial headlands for prevention of beach erosion have been shown clearly on Misawa’s coast. The artificial headland method for beach erosion is effective on the coast where coastal sand drifts move along the shoreline.