Abstract
Impact of high tide and high waves due to typhoon No. 10, 2016 was discussed through field surveys under and after the typhoon event. From visual observation and debris carried in the event, maximum run-up height on Sendai Coast was estimated to be about T.P. 4 m. Severe erosion of embankment toe along the coast line near Sendai Port was observed. Due to overtopping of high waves over sand dune, some amount of sediment was transported into Gamo Lagoon.
20 ~ 30 m retreat of shoreline was observed through shoreline analysis based on aerial photographs taken before and after the typhoon. In one or two months after the event, shoreline positions almost reached to the positions before the typhoon mainly due to the contribution of the cross-shore sediment transport. However, the recovery was relatively slow in the area around Gamo Lagoon and Idoura Lagoon where the wave overtopping over the sand dunes were observed during the field survey. In addition to a river mouth and detached breakwaters, some structures revealed to coast line due to the erosion by the 2011 tsunami have effect to block the longshore sediment transport to induce faster recovery of the shore-line on the up-drift side of the longshore sediment transport.
