Notsukezaki is the longest sand spit in Japan, located in the east region of Hokkaido, and the waves and morphology vary along the spit. The main purpose of this study is improving one-line simulation model by optimization of input parameters, and applying this improved model to Notsukezaki. We set boundary condition by investigation of field observation, input time series wave data in every 6 hours from GPV-wave model, and changed the closure depth according to every wave condition. Results of calculation show that the model can predict well the shoreline changes on Notsukezaki.
