Abstract
We conducted field observations (survey of ocean waves/ hydraulic regime, and movements of bottom material/ sand surface) in summer, autumn and winter on Namiitakaigan in Ootsuchi-cho, Iwate prefecture whose sandy beach has disappeared due to the 2011 off the Pacific Coast of Tohoku Earthquake and tsunami, and discussed the possibility of sandy beach restoration by simulation of beach profile change based on the observation findings. As a result, the following matters were found: (1) Namiitakaigan is a sedimentary coast in summer and is encroached at the time of high waves in autumn. However the situation recovers after that, and therefore it is not an eroding coast; (2) As the result of simulation of beach profile change on the present topography, sand repeatedly moves between shoreline and the sea floor at the depth of approximately 15m; and (3) As the result of simulation of drift sand on the case of artificial nourishment to the extent of the same configuration before the earthquake, washed away of sand to the offing is small and sand around the shoreline tends to accumulate. In light of these facts, it is presumed that artificial nourishment is highly likely to restore sandy beach on the coast.
